[Federal Register Volume 59, Number 107 (Monday, June 6, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-13561]
[[Page Unknown]]
[Federal Register: June 6, 1994]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 63
[AD-FRL-4891-8]
National Emission Standards for Hazardous Air Pollutants for
Source Categories: Aerospace Manufacturing and Rework
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule and notice of public hearing.
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SUMMARY: The proposed standards would limit emissions of hazardous air
pollutants (HAP) from new and existing commercial, civil, and military
aerospace original equipment manufacturing (OEM) and rework facilities
that are major sources of HAP emissions. A major source is defined in
section 112(a) of the Clean Air Act as amended in 1990 (Act) as a
source that emits, or has the potential to emit, considering controls,
10 tons per year (tpy) or more of any individual HAP or 25 tpy or more
of any combination of HAP. The proposed standards implement section
112(d) of the Act, which requires the Administrator to regulate
emissions of the HAP listed in section 112(b) of the Act. Many of these
pollutants are emitted from cleaning, primer, topcoat, depainting, and
chemical milling maskant operations. These operations are being covered
in the proposed rule. The intent of the proposed rule is to protect the
public health by requiring new and existing major sources to control
HAP emissions to the level attainable by the maximum achievable control
technology (MACT). The EPA is also proposing Method 309 with the
standards. Method 309 would be used to determine the rolling material
balance period for carbon adsorbers.
A public hearing will be held, if requested, to provide interested
persons an opportunity for oral presentation of data, views, or
arguments concerning the proposed standards.
DATES: Comments: Comments must be received on or before August 5, 1994.
ADDRESSES: Comments: Comments should be submitted (in duplicate, if
possible) to: Air and Radiation Docket and Information Center (6102),
ATTN: Docket No. A-92-20, U.S. Environmental Protection Agency, 401 M
Street, SW., Washington, DC 20460. Public Hearing: If anyone contacts
the EPA requesting a public hearing, the hearing will be held at the
EPA Office of Administration Auditorium in Research Triangle Park,
North Carolina. Persons wishing to present oral testimony must contact
Ms. Julia Latta, Standards Development Branch (MD-13), U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina
27711, telephone number (919) 541-5578 by July 1, 1994.
Background Information Document: The background information
document (BID) may be obtained from the U.S. EPA Library (MD-35),
Research Triangle Park, North Carolina 27711, telephone number (919)
541-2777. Please refer to ``National Emission Standards for Hazardous
Air Pollutants for Source Categories: Aerospace Manufacturing and
Rework--Background Information for Proposed Standards,'' EPA-453/R-94-
036a.
Docket: Docket No. A-92-20, containing supporting information used
in developing the proposed rule, is available for public inspection and
copying between 8:30 a.m. and 3:30 p.m., Monday through Friday, at the
EPA's Air and Radiation Docket and Information Center, Waterside Mall,
room 1500, 1st Floor, 401 M Street, SW., Washington, DC 20460. A
reasonable fee may be charged for copying.
FOR FURTHER INFORMATION CONTACT: For information concerning the
proposed rule, contact Ms. Vickie Boothe at (919) 541-0164, Standards
Development Branch, Emission Standards Division (MD-13), U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina
27711.
SUPPLEMENTARY INFORMATION: The information presented in this preamble
is organized as follows:
I. Background
II. Summary of the Proposed Rule
A. Applicability
B. Proposed Standards for Affected Sources
C. Compliance Dates
D. Compliance Extensions
E. Compliance Testing and Monitoring
F. Recordkeeping and Reporting Requirements
III. Summary of Environmental, Energy, and Economic Impacts of the
Proposed Rule
A. Emission Reductions
B. Secondary Environmental Impacts
C. Energy Impacts
D. Cost Impacts
E. Economic Impacts
IV. Process Descriptions and Control Technologies
A. Process Descriptions
B. Control Techniques
V. Rationale for the Proposed Rule
A. Regulatory Development Process for NESHAP
B. Determining Maximum Achievable Control Technology (MACT)
``Floors''
C. Selection of Pollutants and Source Category(ies)
D. Selection of Emission Points Covered by the Proposed Rule
E. Selection of the Basis for the Proposed Rule
F. Selection of the Format of the Proposed Rule
G. Selection of Emission Test Methods and Monitoring
Requirements
H. Selection of Recordkeeping and Reporting Requirements
I. Selection of Compliance Deadlines
J. Operating Permit Program
K. Solicitation of Comments
VI. Administrative Requirements
A. Public Hearing
B. Docket
C. Executive Order 12866
D. Paperwork Reduction Act
E. Regulatory Flexibility Act
F. Clean Air Act Section 117
G. Regulatory Review
VII. Statutory Authority
The proposed regulatory text is not included in this Federal
Register notice, but is available in Docket No. A-92-20 or by written
or telephone request from the Air and Radiation Docket and Information
Center (see ADDRESSES). This notice with the proposed regulatory
language is also available on the Technology Transfer Network (TTN),
one of EPA's electronic bulletin boards. The TTN provides information
and technology exchange in various areas of air pollution control. The
service is free, except for the cost of a phone call. Dial (919) 541-
5742 for up to a 14,400 bps modem. If more information on TTN is
needed, call the HELP line at (919) 541-5384.
I. Background
The Act requires, under section 112, that EPA evaluate and control
emissions of HAP. The control of HAP is to be achieved through
promulgation of emission standards under sections 112(d) and (f) for
categories of sources that emit HAP. Pursuant to section 112(c) of the
Act, EPA published in the Federal Register the initial list of source
categories that emit HAP on July 16, 1992 (57 FR 31576). This list
includes major and area sources of HAP that the EPA intends to regulate
before November of the year 2000.
For the purposes of the proposed rule, aerospace industries refers
to all facilities that manufacture aerospace vehicles or components and
all facilities that rework (including repair) these aerospace vehicles
or components. Aerospace vehicle or component is defined as any
fabricated part, processed part, assembly of parts, or completed unit
of any aircraft including, but not limited to, airplanes, helicopters,
missiles, rockets, and space vehicles.
Section 183(b)(3) of the Act requires the Administrator to issue
control techniques guidelines (CTG) for volatile organic compound (VOC)
emissions from aerospace coatings and solvents to such levels as the
Administrator determines are achievable through adoption of best
available control measures (BACM). The EPA is required to take into
account the applicable requirements of section 112 in developing the
guidelines.
The organic HAP emissions limitations described in the remainder of
this notice also address the VOC emissions from aerospace coatings and
solvents. Thus, the control techniques evaluated for the MACT standard
are also applicable to VOC emissions.
The EPA traditionally issues a draft CTG containing recommended
control levels for public comment. Rather than issue a separate draft
CTG in this case, the EPA is using this notice to request public
comment on a draft BACM, which is the same as the proposed MACT for
coatings and solvents. Comments received on the proposed MACT rule will
also be considered in formulating a final BACM.
The information described here will also serve to provide guidance
to the States for developing VOC rules to meet other Clean Air Act
requirements.
Certain low-usage coatings were not addressed in the NESHAP. These
coatings are adhesives, sealants, and 30 specialty coatings which
represent less than 6 percent of the total HAP emissions from the
industry. Also, the EPA data analyses indicate that the MACT floor for
these coatings would be no control. The EPA is requesting public
comment on the need for a separate CTG providing guidance for the
control of these coatings.
II. Summary of the Proposed Rule
Table 1 provides an overview of the proposed rule, including
applicability; the standards for each affected source; test methods and
procedures; and monitoring, recordkeeping, and reporting requirements.
Table 1. Summary of Subpart GG of 40 CFR Part 63--National Emission Standards for Aerospace Manufacturing and
Rework Facilities
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Affected source Requirement Description
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Aerospace Facilities............ Applicability: General This rule applies to facilities engaged in
Information. original equipment manufacture and rework
of aerospace components and assemblies and
that are major sources as defined in 40 CFR
part 63. Specific operations are covered by
the rule. (63.741)
Estimated Number of Facilities.. Over 2,800 facilities are expected to be
affected by the rule. Applicable SIC codes
include 3720, 3721, 3724, 3728, 3760, 3761,
3764, 3765, and 4581.
Permit Requirements............. 1. Major sources required to obtain
operating permit in State where facility is
located according to procedures in 40 CFR
part 70 and applicable State regulations.
(63.741(d))
All Affected Sources............ Standards....................... 1. Comply with Secs. 63.4 through Sec. 63.6
of the General Provisions of 40 CFR part
63, Subpart A.\1\ (63.743(a))
2. Submit an operation and maintenance plan.
(63.743(b))
3. Obtain approval to use control device not
listed in this subpart. (63.743(c))
4. Wastes subject to RCRA are exempt from
the waste storage and handling requirements
of this subpart. (63.741(e))
Compliance Dates................ As provided for in the General
Provisions,\2\ within 3 years after the
effective date for existing sources and no
later than the standards' effective date or
upon startup, as appropriate, for new and
reconstructed sources. (63.749(a))
Test Methods and Procedures..... See individual affected sources. Also,
comply with Sec. 63.7 of the General
Provisions. (63.750(q))
Monitoring Requirements......... See individual affected sources. Also,
generally same as in Sec. 63.8(f) and (g)
of the General Provisions. (63.751(e) and
(f))
Recordkeeping Requirements...... Comply with Sec. 63.10 of the General
Provisions.\3\ (63.752(a))
Reporting Requirements.......... 1. Comply with Secs. 63.9 and 63.10 of the
General Provisions.\4\ (63.753(a)(1) and
(3))
2. Operating permit application can be used
for initial notification. (63.753(a)(2))
Cleaning Operations............. Standards....................... Housekeeping measures for all cleaning
operations at a facility subject to this
subpart. Measures address placing solvent
laden cloth or paper in closed containers,
storing fresh and used cleaning solvent in
closed containers, and minimizing losses
during handling and transfer. (63.744(a))
Test Methods and Procedures..... None.
Monitoring Requirements......... None.
Recordkeeping Requirements...... The name, HAP content of each cleaning
solvent, and supporting documentation.
(63.752(b)(1))
Reporting Requirements.......... Semiannual
1. New cleaning solvents that contain no
HAP. (63.753(b)(1)(i))
2. Discontinued cleaning solvents.
(63.753(b)(1)(ii))
Hand-Wipe Cleaning Operations... Standards....................... 1. Except for spray gun cleaning, all hand-
wipe cleaning solvent must meet either a
composition requirement or have a vapor
pressure less than 45 mm Hg. (63.744(b))
2. List of cleaning operations exempt from
composition and vapor pressure
requirements. (63.744(e))
Test Methods and Procedures..... 1. Composition determination through
manufacturer's data. (63.750(a))
2. Vapor pressure determination through
readily available sources if single
component; ASTM E 260-85 for multiple
component solvents. (63.750(b))
Monitoring Requirements......... For enclosed spray gun cleaners, visual
inspection for leaks at least once per
month. (63.751(a))
Recordkeeping Requirements...... 1. If complying with composition
requirements, name, data/calculations, and
annual volumes. (63.752(b)(2))
2. If complying as result of vapor pressure,
name, vapor pressure, data/calculations/
test results, and monthly volumes.
(63.752(b)(3))
3. For ``non-compliant'' cleaning solvents
used in exempt operations, daily volumes by
operation, and parts/assemblies cleaned.
(63.752(b)(4))
Reporting Requirements.......... Semiannual
1. Noncompliant solvent usage.
(63.753(b)(1)(iii))
2. New solvents and vapor pressure or
composition. (63.753(b)(1)(iv))
Annual
3. Everything is in compliance.
(63.753(b)(2))
Spray Gun Cleaning.............. Standards....................... 1. Use one of four specified techniques or
an equivalent. (63.744(c))
2. For enclosed spray gun cleaners, repair
as soon as practicable, but within 15 days.
(63.744(c)(1)(ii))
Test Methods and Procedures..... None.
Monitoring Requirements......... None.
Recordkeeping Requirements...... Record all leaks, including source
identification and dates leaks found and
repaired. (63.752(b)(5))
Reporting Requirements.......... Semiannual
1. Noncompliant spray gun cleaner used.
(63.753(b)(1)(v))
2. Leaks of enclosed spray gun cleaners not
repaired within 15 days of detection.
(63.753(b)(1)(vi))
Annual
3. Everything is in compliance.
(63.753(b)(2))
Flush Cleaning.................. Standards....................... Operating procedures specify emptying into
enclosed container or collection system or
equivalent. (63.744(d))
Test Methods and Procedures..... None.
Monitoring Requirements......... None.
Recordkeeping Requirements...... None.
Reporting Requirements.......... Annual
Everything is in compliance. (63.753(b)(2))
Primer and Topcoat Application Standards....................... Uncontrolled Primers
Operations. 1. Organic HAP content limit: 350 grams/
liter (2.9 lbs/gallon)(less water) as
applied. (63.745(b)(1))
2. VOC content limit: 350 grams/liter (2.9
lbs/gallon) (less water and exempt
solvents) as applied. (63.745(b)(2))
Uncontrolled Topcoats
3. Organic HAP content limit: 420 grams/
liter (3.5 lbs/gallon)(less water) as
applied. (63.745(b)(3))
4. VOC content limit: 420 grams/liter (3.5
lbs/gallon) (less water and exempt
solvents). (63.745(b)(4))
Uncontrolled Primers and Topcoats
5. Primers and topcoats can achieve
compliance through: (1) being below limit
in themselves or (2) average with compliant
primers. (63.745(d))
6. Primers and topcoats cannot be averaged
together. Controlled and uncontrolled
coatings cannot be averaged together.
(63.745(d)(2)(ii) and (d)(2)(iii))
Controlled Primers and Topcoats
7. If control device is used, must be
designed to capture and control all
emissions from the application operation
and must achieve an overall control
efficiency of at least 81%. (63.745(c))
All Primers and Topcoats
8. Specific application techniques must be
used. If alternative is sought, can only be
used if emissions are less than or equal to
HVLP or electrostatic spray application
techniques as demonstrated under actual
production conditions. (63.745(e)(1))
9. All application equipment must be
operated according to manufacturer's
specifications. (63.745(e)(2))
10. Exemptions from 8 above provided for
certain situations. (63.745(e)(3))
11. Operating requirements for the
application of primers that contain
inorganic HAP, including control with
either particulate filters or waterwash and
shutdown if pressure falls outside
manufacturer's specified operating limits.
(63.745(f)(1) through (4))
12. Exemptions from 11 provided for certain
application operations. (63.745(f)(5))
Performance Test Periods and 1. Test Periods For compliant coatings: each
Tests. 30-day period. For ``averaged'' coatings:
each 24-hour period. For ``controlled''
coatings, non-carbon adsorber: three 1-hour
runs. For ``controlled'' coatings, carbon
adsorber: each rolling period.
(63.749(d)(1))
2. Performance tests. Initial performance
test for all control devices to demonstrate
compliance with overall control efficiency
requirement. (63.749(d)(2))
Test Methods and Procedures..... 1. Organic HAP level determination
procedures. (63.750(c) and (d))
2. VOC level determination procedures.
(63.750(e) and (f))
3. Overall control efficiency of carbon
adsorber determined using mass balance
calculation in 40 CFR 60.433; for other
control devices, determine capture
efficiency and destruction efficiency. For
capture efficiency, use Procedure T in
Appendix B to 40 CFR 52.741 for total
enclosures and 40 CFR 52.741(a)(4)(iii)
procedures for all other enclosures.
(63.750(g) and (h))
4. For alternative application methods,
first determine emission levels for initial
90-day period using only HVLP or
electrostatic. Then use alternative
application method for period of time
necessary to coat equivalent amount of
parts with same coatings. Alternative
application method may be used when
emissions generated during the test period
are less than or equal to the emissions
generated during the initial 90-day period.
Dried film thickness must be within
specification for initial 90-day period.
(63.750(i))
Monitoring Requirements......... 1. Temperature sensors with continuous
recorders for incinerators, and install,
calibrate, maintain, and operate
temperature monitors according to
manufacturer's specifications. (63.751(b))
2. Continuously monitor pressure drop across
filter or waterwash. (63.751(c))
Recordkeeping Requirements...... 1. Name and organic HAP and VOC contents for
all primers and topcoats. (63.752(c)(1))
2. For ``compliant'' coatings, organic HAP
and VOC contents as applied, data/
calculations used to determine them, and
monthly usage. (63.752(c)(2))
3. For ``averaged'' coatings, daily values
of HAP and VOC contents (Ha and Ga) and
data calculations used to calculate Ha and
Ga. (63.752(c)(3))
4. For ``controlled'' coatings
(incinerator), overall control efficiency
and incinerator temperature(s).
(63.752(c)(4))
5. For ``controlled'' coatings (carbon
adsorber), overall control efficiency and
length of rolling period and all supporting
data/calculations. (63.752(c)(5))
6. Pressure drop across filters/waterwash
once per shift, and acceptable limits.
(63.752(d))
Reporting Requirements.......... Semiannual
1. All instances where organic HAP/VOC
levels were exceeded. (63.753(c)(1)(i) and
(ii))
2. Control device exceedances (out-of-
compliance). (63.753(c)(1) (iii), (iv) and
(v))
3. Periods when operation not immediately
shut down due to pressure drop being
outside limits. (63.753(c)(1)(vi))
4. New control devices. (63.753(c)(1)(vii))
Annual
5. Number of times the pressure drop limits
were exceeded. (63.753(c)(2))
6. Everything is in compliance.
(63.753(c)(2))
Depainting Operations........... Applicability................... Applies to the entire aerospace vehicle.
Does not apply to parts or units normally
removed. Wings and stabilizers always
covered. (63.746(a))
Standards....................... 1. Unless exempted, no organic HAP are to be
emitted from depainting operations. (63.746
(b)(1), (b)(3))
2. Requirement to minimize HAP during
periods of non-chemical based equipment
malfunction. (63.746(b)(2))
3. Use of organic HAP-containing strippers
for spot stripping and decal removal
limited to 26 gallons per aircraft per year
for commercial aircraft and 50 gallons per
aircraft per year for military aircraft.
(63.746(c))
4. Operating requirements for depainting
operations generating airborne inorganic
HAP, including control with particulate
filters that are at least 99% efficient.
(63.746(d))
Performance Test Periods and 1. For no organic HAP emissions: each 24-
Tests. hour period. (63.749(f)(1))
2. For spot stripping and decal removal
usage limits: each calendar year.
(63.749(f)(1))
3. Initial performance test to demonstrate
compliance with percent reduction
efficiency requirement for particulate
filters. (63.749(f)(2))
Test Methods and Procedures..... 1. Use manufacturer's data (or approved
alternative) to determine organic HAP
content. (63.750(j))
2. Procedures provided for determining
gallons of HAP containing stripper used for
aircraft. (63.750(k))
3. Use EPA Method 5 to determine particulate
filter control efficiency. (63.750(l))
Monitoring Requirements......... Continuously monitor pressure drop across
filter. (63.751(d))
Recordkeeping Requirements...... 1. Name, organic HAP content and supporting
documentation, and monthly volume of all
organic HAP-containing chemical strippers.
(63.752(e)(1))
2. List of parts/assemblies normally
removed. (63.752(e)(2))
3. For non-chemical based equipment, name
and type, and malfunction information
including dates, description, and
alternative methods used. (63.752(e)(3))
4. For spot stripping and decal removal,
annual volume used, annual average volume
per aircraft, and all data/calculations
used to calculate volume per aircraft.
(63.752(e)(4))
5. The pressure drop across the filter once
per shift, pressure drop limits specified
by manufacturers, and control efficiency
including test results/data/calculations.
(63.752(e)(5))
Reporting Requirements.......... Semiannual
1. Emission of organic HAP from nonexempted
depainting operations. (63.753(d)(1)(i))
2. New and reformulated chemical strippers
and HAP contents. (63.753(d)(1) (ii), (iii)
and (iv))
3. New non-chemical based depainting
techniques. (63.753(d)(1)(v))
4. Malfunction information on non-chemical
based techniques including dates,
description, and alternative methods used.
(63.753(d)(1)(vi))
5. Periods when operation not immediately
shut down due to pressure drop being
outside limits. (63.753(d)(1)(vii))
6. List of new/discontinued aircraft models
and, for new models, list of parts normally
removed for depainting.
(63.753(d)(1)(viii))
Annual
7. Exceedances of average annual volume
limits for spot stripping and decal
removal. (63.753(d)(2)(i))
8. Everything is in compliance.
(63.753(d)(2)(ii))
9. Number of times the pressure drop limits
were exceeded. (63.753(d)(2)(iii))
Chemical Milling Maskant Applicability................... Applies only to operations using Type II
Application Operations. chemical milling etchants (63.747(a))
Standards....................... Uncontrolled Maskants
1. Organic HAP emissions: 160
grams/liter (1.3 lbs/gallon) (less water)
as applied. (63.747(c)(1))
2. VOC emissions: 160 grams/liter
(1.3 lbs/gallon) (less water and exempt
solvents) as applied. (63.747(c)(2))
3. Maskants can achieve compliance through:
(1) being below limits by themselves or (2)
averaging with compliant maskants.
(63.747(e))
4. Both controlled and uncontrolled maskants
cannot be averaged together.
Controlled Maskants
5. If control device is used, must be
designed to capture and control all
emissions from maskant operation and must
achieve an overall control efficiency of at
least 81%. (63.747(d))
Performance Test Periods and 1. Test Periods. For compliant maskants:
Tests. each 30-day period. For ``averaged''
maskants: each 24-hour period. For
``controlled'' coatings, carbon adsorber:
each rolling period. For ``controlled''
coatings, non-carbon adsorber: three 1-hour
runs. (63.749(g)(1))
2. Initial performance test required for all
control devices to demonstrate compliance
with overall control efficiency
requirement. (63.749(g)(2))
Test Methods and Procedures..... Procedures provided essentially identical to
those for primers and topcoats for organic
HAP and VOC content levels. Use of Method
309 for determining rolling period for
carbon adsorber. (63.750(m)-(p))
Monitoring Requirements......... Same as for primers and topcoats if
incinerators are used.
Recordkeeping Requirements...... Same as for primers and topcoats.
(63.752(f))
Reporting Requirements.......... Semiannual
1. Exceedances of organic HAP/VOC levels.
(63.753(e)(1)(i) and (ii))
2. Control device exceedances (out of
compliance). (63.753(e)(1)(iii))
3. New maskants. (63.753(e)(1)(iv))
4. New control devices. (63.753(e)(1)(v))
Annual
5. Everything is in compliance.
(63.753(e)(2))
Waste Handling and Storage Applicability................... Wastes that are subject to RCRA are exempt
Operations. from the requirements of this subpart.
(63.741(e))
Standards....................... Unless subject to RCRA, work practice
requirements to minimize spills during
handling and transfer and storage in close
containers. (63.748)
Test Methods and Procedures..... None.
Monitoring Requirements......... None.
Recordkeeping Requirements...... Identification of each waste stream, whether
or not it is subject to RCRA, and
supporting documentation. (63.752(g))
Reporting Requirements.......... Semiannual
1. Any change in RCRA status of waste
stream, any new waste stream, and its RCRA
status. (63.753(f)(1))
Annual
2. No new waste streams and no change in
RCRA status of existing waste streams.
(63.753(f)(2))
----------------------------------------------------------------------------------------------------------------
\1\The EPA promulgated regulations for subpart A of 40 CFR 63, which were published in the Federal Register on
March 16, 1994 at 59 FR 12408.
\2\Ibid.\3\Ibid.\4\Ibid.
A. Applicability
1. Description of the Source Category
The proposed rule would apply to each aerospace manufacturing and
rework facility that is a major source, as defined under section 112(a)
of the Act. A major source is one that emits or has the potential to
emit, considering controls, 9.1 megagrams per year (Mg/yr) (10 tpy) or
more of any hazardous air pollutant or 22.7 Mg/yr (25 tpy) or more of
any combination of hazardous air pollutants for all activities
conducted at the facility. An aerospace facility is defined as a
facility that produces in any amount an aerospace vehicle or component,
or a facility that reworks (or repairs) these vehicles or components.
Aerospace operations at any major source that conduct both aerospace
and non-aerospace work would be subject to the proposed standards,
regardless of the relative proportion of aerospace and non-aerospace
work at the facility.
While the proposed rule applies only to major sources, the EPA
requests comment on whether all or some of its requirements should be
applied to non-major sources. The Agency solicits available information
from state and local air pollution control agencies and others on the
nature, number and location of non-major aerospace facilities, the
quantities and types of hazardous air pollutants they emit, the impact
of these emissions on health and the environment, and the extent to
which these emissions already are controlled. Comments also are
requested on the economic and other impacts that would result from
applying requirements of the proposed rule to these smaller sources.
In general, aerospace facilities are covered by the SIC codes
listed in Table 2. However, facilities classified under other SIC codes
may be subject to the proposed standards if the facility meets the
definition of a major source and the definition of an aerospace
facility.
Based on information obtained through the Federal Aviation
Administration and the U.S. Department of Commerce--Bureau of the
Census, there are an estimated 2,869 aerospace facilities that will be
subject to the proposed standards. Of this number, 1,395 manufacture or
rework commercial products, and 1,474 manufacture or rework military
products. The combined HAP emissions from these facilities are
estimated to be over 189,000 Mg/yr (208,000 tpy).
In addition to these facilities, there are numerous subcontractors
that manufacture or rework aerospace vehicles or components. The
subcontractors may work directly for the
Table 2.--Aerospace Manufacturing SIC Codes
------------------------------------------------------------------------
SIC Code Description
------------------------------------------------------------------------
3720 Aircraft and Parts.
3721 Aircraft.
3724 Aircraft Engines and Engine Parts.
3728 Aircraft Parts and Equipment.
3760 Guided Missiles, Space Vehicles, and Parts.
3761 Guided Missiles and Space Vehicles.
3764 Space Propulsion Units and Parts.
3769 Space Vehicle Equipment.
Aerospace Rework SIC Code
4581 Airports, Flying Fields, and Services.
------------------------------------------------------------------------
OEM or rework facilities, or indirectly through first line
subcontractors. Since many of these subcontractors perform various
types of work, they are often classified under non-aerospace SIC codes.
Consequently, an estimate of the number of subcontractors cannot be
made. One company alone, however, employs the services of over 5,000
subcontractors.
2. Affected Sources
The proposed rule would limit organic HAP emissions from the
following sources at aerospace facilities: cleaning operation, primer
application operation, topcoat application operation, depainting
operation, chemical milling maskant application operation, and the
handling and storage of waste. The proposed rule would also limit
inorganic HAP emissions from primer, topcoat, and depainting
operations.
Organic HAP emissions from primer, topcoat, and chemical milling
maskant application operations occur from the evaporation of the
solvent contained in the coatings. These emissions occur during the
application of the coatings on aerospace vehicles or parts, which may
take place in large open areas, such as hangars, or in partially or
fully enclosed spaces, such as within spray booths.
Organic HAP emissions from cleaning and depainting operations occur
from the evaporation of the volatile portion of the cleaning solvents
or chemical strippers. Cleaning emissions are nearly always fugitive in
nature and occur at essentially every processing step. Emissions from
depainting are typically fugitive in nature since the operation is
carried out within a large hangar or in open tanks.
Organic HAP emissions from waste occur from evaporation of the
volatile portion of the waste while it is being handled or stored.
These emissions are fugitive in nature, occurring from each waste
container.
Inorganic HAP emissions from primer and topcoat application
operations occur during the application of the primer or topcoat. These
inorganic HAP emissions are paint particulates, commonly referred to as
``overspray,'' that do not adhere to the surface being coated. Like the
organic HAP emissions from the operations, the emissions of the
inorganic HAP occur in large open areas, such as hangars, or in
partially or fully enclosed spaces, such as within spray booths.
Inorganic HAP emissions from depainting operations occur from most
non-chemical methods, such as plastic media blasting, used to strip an
aerospace vehicle. (Chemical stripping techniques do not release
inorganic HAP.) These emissions occur as particulates generated during
the blasting process. The operation is typically carried out within a
large hangar equipped with a ventilation system and particulate
filtration device (e.g., a baghouse). The inorganic HAP that are
released from the depainting operations are primarily found in the
paint being stripped, although some stripping media may contain trace
amounts of inorganic HAP.
B. Proposed Standards for Affected Sources
In addition to the standards for affected sources as discussed
below, the proposed rule contains general standards. The general
standards stipulate that all affected sources subject to the proposed
rule are also subject to, as appropriate, Sec. 63.4, Sec. 63.5, and
Sec. 63.6 of subpart A of 40 CFR part 63.1 However, certain time
frames specified in these sections have been changed in the proposed
rule as follows:
---------------------------------------------------------------------------
\1\The EPA promulgated regulations for subpart A of 40 CFR part
63, which were published in the Federal Register on March 16, 1994
at 59 FR 12408.
---------------------------------------------------------------------------
(1) All affected sources shall submit any request for an extension
of compliance not later than 12 months before the affected source's
compliance date regardless of whether sources are included in emissions
averaging or not, rather than not later than 18 months before the
affected source's compliance date for sources that are including
emission points in an emissions average as provided for in
Sec. 63.6(i)(4)(i)(B),
(2) The Administrator (or the State with an approved permit
program) will notify the owner or operator in writing of his/her
intention to deny approval of a request for an extension of compliance
submitted under either Sec. 63.6(i)(4) or (i)(5) within 60 calendar
days after receipt of sufficient information to evaluate the request,
rather than notifying the owner of his/her approval or intention to
deny approval of a request for an extension of compliance within 30
calendar days as provided for in Sec. 63.6(i)(12)(i) and
Sec. 63.6(i)(13)(i). In addition, if the Administrator does not notify
the owner or operator in writing of his/her intention to deny approval
within 60 calendar days after receipt of sufficient information to
evaluate a request for an extension of compliance, then the request
shall be considered approved,
(3) The Administrator (or the State) will notify the owner or
operator in writing of the status of his/her application submitted
under Sec. 63.6(i)(4)(ii) (that is, whether the application contains
sufficient information to make a determination) within 30 calendar days
after receipt of the original application and within 30 calendar days
after receipt of any supplementary information that is submitted,
rather than 15 calendar days as provided for in Sec. 63.6(i)(13)(i). In
addition, if the Administrator does not notify the owner or operator in
writing of the status of his/her application within 30 calendar days
after receipt of the original application and within 30 calendar days
after receipt of any supplementary information that is submitted, then
the information in the application or the supplementary information is
to be considered sufficient upon which to make a determination,
(4) Each owner or operator is to be provided 30 calendar days to
present additional information to the Administrator after he/she is
notified of the intended denial of a compliance extension request
submitted under either Sec. 63.6(i)(4) or Sec. 63.6(i)(5), rather than
15 calendar days as provided for in Sec. 63.6(1)(12)(iii)(B) and
Sec. 63.6(i)(13)(iii)(B),
(5) Each owner or operator who has submitted an extension request
application under Sec. 63.6(i)(5) is to be provided 30 calendar days to
present additional information or arguments to the Administrator after
he/she is notified that the application is not complete, rather than 15
calendar days as provided for in Sec. 63.6(i)(13)(ii), and
(6) A final determination to deny any request for an extension
submitted under either Sec. 63.6(i)(4) or Sec. 63.6(i)(5) will be made
within 60 calendar days after presentation of additional information or
argument (if the application is complete), or within 60 calendar days
after the final date specified for the presentation if no presentation
is made, rather than 30 calendar days as provided for in
Sec. 63.6(i)(12)(iv) and Sec. 63.6(i)(13)(iv).
In addition, the proposed rule requires each owner or operator who
uses a control device or equipment to control HAP emissions to prepare
an operation and maintenance plan in accordance with Sec. 63.6 of
subpart A of 40 CFR part 63.2 In addition to the information
required in Sec. 63.6, the proposed rule requires that the owner or
operator of the control device or equipment include the following
information: (1) The operation and maintenance criteria for each air
pollution control device or equipment, including a standardized
checklist to document the operation and maintenance of the equipment;
(2) a systematic procedure for identifying malfunctions and for
reporting them immediately to supervisory personnel; and (3) procedures
to be followed to ensure that equipment or process malfunctions due to
poor maintenance or other preventable conditions do not occur.
---------------------------------------------------------------------------
\2\Ibid.
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The general standards also state that an owner or operator who uses
an air pollution control device or equipment not listed in the proposed
rule must submit to the Administrator for approval a description of the
device, test data verifying the performance of the device or equipment
for HAP and/or VOC emissions, appropriate operating parameters that
would be monitored to establish compliance with the proposed standards,
and a copy of the inspection and maintenance plan required under
Sec. 63.6 of 40 CFR part 63.
Finally, Sec. 63.6(g) of subpart A of 40 CFR part 63 allows an
owner or operator of an affected source to use alternative means of
compliance. This allows the development and use of new technology not
known or not demonstrated at the time the rule was promulgated.
The affected sources for the proposed standards are defined as
follows: (1) Each cleaning operation (all hand-wipe cleaning operations
constitute an affected source, each spray gun cleaning operation
constitutes an affected source, and all flush cleaning operations
constitute an affected source); (2) each primer application operation,
which includes all primer applications at the facility; (3) each
topcoat application operation, which includes all topcoat applications
at the facility; (4) each depainting operation, which includes all
depainting of the outer surface of aerospace vehicles at the facility;
(5) each chemical milling maskant application operation, which includes
all chemical milling maskant applications at the facility for
subsequent use in Type II chemical milling etchants; and (6) each waste
storage and handling operation, which includes all waste handling and
storage at the facility.
The proposed standards also specify that HAP-containing waste that
is subject to the provisions of RCRA would not be subject to the waste
handling and storage requirements of the proposed standards. The EPA
included this provision so that the proposed standards would not
require less strict handling and storage of waste than the RCRA
requirements.
The following paragraphs summarize the proposed standards for each
affected source.
1. Cleaning Operation
The proposed standards for the cleaning operation, including those
specific to hand-wipe, spray gun, and flush cleaning operations, would
apply to all new and existing affected sources. The proposed standards
would require that all fresh and spent cleaning solvents be stored in
closed containers and that solvent-laden cloth, paper, or other
material be placed in bags or other closed containers immediately after
use. The bags or containers would be required to be kept closed at all
times (except when depositing or removing material) and of such design
so as to contain the vapors of the cleaning solvent. In addition, the
proposed standards would require the owner or operator to implement
handling and transfer procedures to minimize spills during filling and
transferring the cleaning solvent to or from enclosed systems, vats,
waste containers, and other cleaning operation equipment that holds or
stores fresh or spent cleaning solvents. The above requirements are
known collectively as housekeeping measures.
The proposed standards for the hand-wipe cleaning operation would
require the use of a cleaning solvent that conforms to the approved
composition list detailed in Table 3 or a cleaning solvent that has a
vapor pressure less than or equal to 45 millimeters of mercury (mm Hg)
at 20 deg.C (24.1 in. H2O at 68 deg.F).
Table 3.--Composition Requirements for Approved Cleaning Solvents
----------------------------------------------------------------------------------------------------------------
Cleaning solvent type Composition requirements
----------------------------------------------------------------------------------------------------------------
Aqueous.......................... Cleaning solvents in which water is the primary ingredient (80
percent of solvent as applied must be water). Aqueous solvents must be non-
flammable, non-combustible, and 100 percent soluble in water. Detergents,
surfactants, and bioenzyme mixtures and nutrients may be combined with the
water along with a variety of additives such as organic solvents (e.g., high
boiling point alcohols), builders, saponifiers, inhibitors, emulsifiers, pH
buffers, and antifoaming agents.
Hydrocarbon-Based................ Cleaners that are composed of a mixture of hydrocarbons and oxygenated
hydrocarbons and have a maximum vapor pressure of 7 mm Hg at 20 deg.C (3.75
in. H2O at 68 deg.F). These cleaners also contain no HAP or ozone depleting
compounds.
----------------------------------------------------------------------------------------------------------------
The EPA is proposing a work practice standard for the cleaning of
spray guns at all new and existing affected sources. The proposed rule
would require all spray guns to be cleaned by one or more of the
following methods (or their equivalent): (1) Use of an enclosed spray
gun cleaning system that is kept closed when not in use, (2)
nonatomized discharge of solvent into a waste container that is kept
closed when not in use, (3) disassembly of the spray gun and cleaning
in a vat that is kept closed when not in use, and (4) atomized spray
into a waste container that is fitted with a device designed to capture
atomized solvent emissions. In addition, the EPA is proposing that
leaks from enclosed spray gun cleaners be repaired as soon as
practicable but no later than 15 days from when the leak is first
discovered. The EPA is also proposing a work practice standard for the
flush cleaning of parts, assemblies, and components of a coating unit.
Under the proposed rule, each time a part, assembly, or component of a
coating unit (with the exception of spray guns) is flush cleaned, the
spent cleaning solvent would be emptied into an enclosed container or
collection system that is kept closed when not in use.
The following cleaning operations, which would still be required to
comply with the proposed housekeeping requirements, would be exempt
from the proposed cleaning solvent composition and vapor pressure
requirements:
(1) Cleaning during the manufacture, assembly, installation, or
testing of components of breathing oxygen systems that are exposed to
the breathing oxygen,
(2) Cleaning during the manufacture, assembly, installation, or
testing of parts, subassemblies, or assemblies that are exposed to
strong oxidizers or reducers (e.g., nitrogen tetroxide, liquid oxygen,
hydrazine),
(3) Cleaning and surface activation prior to adhesive bonding,
(4) Cleaning of electronics and assemblies containing electronics,
(5) Cleaning of aircraft fluid systems that are exposed to the
fluid,
(6) Cleaning of fuel cells, fuel tanks, and limited access spaces,
(7) Surface cleaning of solar cells, coated optics, and thermal
control surfaces,
(8) Cleaning during fabrication, assembly, installation, and
maintenance of upholstery, curtains, carpet, and other textile
materials used on the interior of the aircraft,
(9) Cleaning of metallic and non-metallic materials used in
honeycomb cores during the manufacture of these cores, and cleaning of
the completed cores used in the manufacture of aerospace vehicles or
components,
(10) Cleaning of polycarbonate substrates, and
(11) Cleaning and solvent usage associated with production,
research, development, quality control, and laboratory testing.
2. Primer and Topcoat Application Operations
The proposed standards for primer and topcoat application
operations would be the same for all new and existing affected sources.
Standards are being proposed to limit organic and inorganic HAP
emissions from these operations.
a. Organic HAP and VOC emissions. The standards being proposed
would limit the organic HAP emissions from primer application
operations to an equivalent organic HAP content level of 350 grams of
organic HAP per liter (2.9 pounds per gallon (lb/gal)) of primer (less
water) as applied, and from topcoat application operations to an
equivalent organic HAP content level of 420 grams of organic HAP per
liter (3.5 lb/gal) of topcoat (less water) as applied. In addition to
the organic HAP limits, the proposed standards would limit VOC
emissions from primer application operations to an equivalent VOC
content level of 350 grams of VOC per liter (2.9 lb/gal) of primer
(less water and exempt solvents) as applied, and from topcoat
application operations to an equivalent VOC content level of 420 grams
of VOC per liter (3.5 lb/gal) of topcoat (less water and exempt
solvents) as applied. Equivalent organic HAP and VOC content level
means the calculated organic HAP (or VOC) content of coatings that when
multiplied by the usage of the coatings yields the amount of organic
HAP (or VOC) actually emitted to the atmosphere by the use of the
coatings. Exempt solvents are those organic compounds that have been
determined by the EPA to have negligible photochemical reactivity.
The EPA has received information indicating that the organic HAP
and VOC content limits for topcoats do not represent demonstrated
technology for exterior commercial topcoats. Consequently, the EPA is
soliciting comments on whether a separate category should be developed
for exterior commercial topcoats with HAP and VOC content levels higher
than the proposed levels for topcoats. These comments should provide a
technical justification for a higher limit, including why currently
available commercial topcoats cannot be used by all sources.
Sources would be allowed to comply with the proposed organic HAP
and VOC content levels by one or both of the following means: (1) Use
coatings that individually comply with the organic HAP and VOC levels
or (2) use any combination of uncontrolled coatings such that the daily
volume-weighted average organic HAP and VOC contents of these coatings
comply with the organic HAP and VOC levels for that category (averaging
of primers and topcoats together is prohibited). Averaging between
uncontrolled coatings and controlled coatings is prohibited under the
proposed rule.
Instead of complying with the proposed organic HAP and VOC content
levels through compliant coatings or averaging, the proposed standards
allow the use of control devices provided each control device used for
the control of organic HAP or VOC emissions from primer or topcoat
application operations has an overall control efficiency, taking into
account capture and removal efficiency, of greater than or equal to 81
percent. In addition, except for incidental emissions that may escape
from the capture system, the control device cannot be used to control
only a portion of emissions from a coating operation.
Compliance with the proposed organic HAP and VOC content level
standards would be shown on a monthly basis for compliant coatings, and
on a daily basis for coatings complying by averaging. Compliance for
control devices other than carbon adsorbers would be shown on a
continuous basis based on a specific operating parameter or parameters,
such as temperature for incinerators. When a carbon adsorber is used to
comply with the proposed standard, compliance with the 81 percent
overall control efficiency requirement must be demonstrated for each
rolling material balance period. The length of the rolling period will
vary from source to source and is determined by the procedure specified
in proposed Method 309 in the proposed rule. The minimum rolling period
is one day, and the maximum rolling period is 30 days.
The EPA is also proposing an equipment standard for the application
of primers and topcoats. The proposed standard would require the use of
flow coat, roll coat, brush coat, dip coat, electrostatic attraction,
or high volume low pressure (HVLP) spray guns other than for the
exemptions listed below. All application equipment would be required to
be operated and maintained according to manufacturer's specifications
at all times.
The EPA is proposing to allow other application equipment that is
demonstrated to achieve emission levels equivalent to HVLP or
electrostatic spray guns. Compliance must be demonstrated by comparing
the emissions generated by the alternative application method to the
emissions generated by HVLP or electrostatic application methods under
actual production conditions. The alternative method must generate
emissions less than or equal to that generated by HVLP or electrostatic
spray methods.
During the alternative application method test period, the owner or
operator must ensure that the coating dried film thickness is
equivalent to that applied during the initial 90-day test period. This
is required to ensure that the owner or operator does not bias the test
results by applying an excessive amount of coating during the initial
90-day period and applying a minimal amount of coating during the
alternative application method test period. The EPA is requesting
comments on whether the requirements of the proposed standards are
sufficient to ensure that this situation does not occur. Specifically,
comments should address whether detailed recordkeeping should also be
required in order to determine that equivalent dried film thicknesses
were applied.
The EPA is proposing to exempt the following situations and
operations from the proposed equipment standards for the application of
primers and topcoats, although whatever application equipment is used
would still be required to be operated and maintained according to
manufacturers specifications at all times: (1) Any situation that
normally requires the use of an extension on the spray gun to properly
reach limited access spaces, (2) the application of coatings that
contain fillers that adversely affect atomization with HVLP spray guns
and cannot be applied by any of the specified application techniques,
(3) the application of coatings that normally have a dried film
thickness of less than 0.0005 inch and cannot be applied by any of the
specified application techniques, (4) the use of airbrush application
methods for stenciling, lettering, and other identification markings,
and (5) touchup and repair operations.
b. Inorganic HAP emissions. The standards being proposed for
inorganic HAP emissions from primer and topcoat application operations
would apply to those operations that spray apply coatings that contain
inorganic HAP (usually chromium, cadmium, and selenium). Such
operations would be required to be performed in a booth or hangar in
which the air flow is directed across the part or assembly being coated
and exhausted through one or more outlets. This air stream would be
required to pass through either dry particulate filters or a waterwash
system to remove the particulates before exhausting to the atmosphere.
In addition, the pressure drop across the filter or waterwash would
have to be continuously monitored. If the pressure drop moves outside
of the limits specified by the manufacturer to maintain proper
performance of the dry particulate filters or waterwash system, then
the operation must be shut down immediately and corrective action
taken. The process cannot resume until the pressure drop is returned to
the limits specified by the manufacturer.
The EPA is requesting comments on whether pressure drop is an
appropriate parameter on which to make continuous compliance
determinations with the inorganic HAP emission standards. The
possibility exists that different filter or waterwash manufacturers may
specify different pressure drop limits for products with essentially
the same performance. Since the proposed standards rely on pressure
drop as the basis for making compliance determinations, such a
difference would result in different requirements from one facility to
another. Thus, the EPA is requesting comments specifically on whether a
standardized pressure drop limit can be established, or if another
operating parameter exists on which to make compliance determinations
that would be consistent and enforceable for all types and brands of
filters and waterwash systems.
If pressure drop is selected as the parameter to be used to
determine continuous compliance, then a violation of the standards
could occur under one of the following conditions: (1) Whenever the
pressure drop moves outside the limits specified by the manufacturer or
(2) when the pressure drop is found to be outside the specified limits
when monitored and recorded once per operating shift. As the proposed
rule is currently written, a violation would occur in the latter
situation. The EPA is requesting comments on which of these options, or
another option, is most appropriate.
The EPA is proposing to exempt the following list of operations
from the proposed standards for inorganic HAP emissions from primer and
topcoat application operations:
(1) Touch-up of scratched surfaces or damaged paint,
(2) Hole daubing for fasteners,
(3) Touch-up of trimmed edges,
(4) Coating prior to joining dissimilar metal components,
(5) Stencil operations performed by brush or air brush,
(6) Section joining, and
(7) Touch-up of bushings and other similar components.
3. Depainting Operation
Standards are being proposed for both organic HAP emissions and
inorganic HAP emissions from depainting. With the exception of the
proposed standards for spot stripping and decal removal, as discussed
below, the standards being proposed for depainting would be the same
for all new and existing affected sources. The proposed standards would
apply only to the depainting of the outer surface of entire aerospace
vehicles, including the fuselage, wings, and horizontal and vertical
stabilizers of the aircraft, and the outer casing and stabilizers of
missiles and rockets. Standards for the depainting of parts,
subassemblies, radomes, and parts normally removed from the completed
vehicle before depainting are not being proposed at this time. However,
wings and stabilizers would always be required to comply.
a. Organic HAP emissions. The proposed standards would require that
there be no organic HAP emissions from the depainting operation. These
standards could be achieved through the use of (1) chemical strippers
that contain no organic HAP or (2) media blasting equipment, high
intensity ultra-violet light blasting, or any other non-chemical
depainting technique. However, the proposed rule would allow the use of
organic HAP-containing chemical stripper for spot stripping and decal
removal. The proposed rule would limit this use of organic HAP-
containing chemical stripper to an average of 26 gallons per aircraft
for commercial aircraft and 50 gallons per aircraft for military
aircraft, calculated on an annual basis.
Non-chemical-based depainting equipment would be required to be
operated and maintained according to manufacturer's specifications.
During any period of malfunction, the owner or operator would be
allowed to use a substitute material to depaint the vehicles. Unless
the substitute material does not contain any organic HAP, the
substitute material would not be allowed to be used for more than 14
consecutive days.
The proposed rule does not contain an annual limit on the number of
days a source may use HAP-containing chemical strippers during periods
of malfunction of non-chemical-based depainting equipment. The EPA is
requesting comments on whether an annual limit should be imposed and,
if so, technical justification for the number of days specified by the
limit.
b. Inorganic HAP emissions. The proposed rule for inorganic HAP
emissions would apply to those depainting methods (typically blasting
methods) that generate airborne particulate emissions, such as dust and
paint particles, that contain inorganic HAP. The proposed standards
would require that the depainting operation be carried out in an
enclosed hangar and that any air stream removed from the depainting
area be directed through a particulate filter (e.g., panel-type filter
or baghouse) before exhausting to the atmosphere. This filtration
system must have a particulate removal efficiency greater than or equal
to 99 percent, and the pressure drop across the filter must be
continuously monitored. If the pressure drop moves outside of these
limits as recorded each operational shift, then the operation must
immediately be shut down and corrective action taken. The process
cannot resume until the pressure drop is within the limits specified by
the manufacturer.
As described above for primer and topcoat application operations,
the EPA is requesting comments concerning the appropriateness of using
pressure drop to make compliance determinations and what action should
be taken when the pressure drop moves outside of the specified limits.
4. Chemical Milling Maskant Application Operation
The proposed standards for the chemical milling maskant application
operation would be the same for all new and existing affected sources
and applies only to those operations utilizing a Type II chemical
milling etchant. The proposed standards would limit organic HAP
emissions to an equivalent organic HAP content level of 160 grams of
organic HAP per liter (1.3 lb/gal) of chemical milling maskant (less
water) as applied, and limit the VOC emissions to an equivalent VOC
content level of 160 grams of VOC per liter (1.3 lb/gal) of chemical
milling maskant (less water and exempt solvents) as applied.
Alternatively, as for primer and topcoat application operations,
control devices that achieve an overall control efficiency of at least
81 percent and control all emissions (except for incidental emissions)
may be used.
Compliance with the organic HAP and VOC content level standards
would be allowed using one or both of the following means: (1) Use
chemical milling maskants that individually comply with the organic HAP
and VOC content levels or (2) use any combination of chemical milling
maskants such that the daily volume-weighted average organic HAP and
VOC content levels of these chemical milling maskants used in the
chemical milling maskant operation comply with the organic HAP and VOC
content levels. Averaging uncontrolled chemical milling maskants with
controlled chemical milling maskants, however, is prohibited under the
proposed rule.
Compliance with the proposed organic HAP and VOC content level
standards would be shown on a monthly basis for compliant chemical
milling maskants and on a daily basis for chemical milling maskants
complying by averaging. Compliance for control devices other than
carbon adsorbers would be shown on a continuous basis based on a
specific operating parameter or parameters, such as temperature for
incinerators. When a carbon adsorber is used to comply with the
proposed standard, compliance with the 81 percent overall control
efficiency requirement must be demonstrated for each rolling material
balance period. The length of the rolling period will vary from source
to source and is determined by the procedure specified in proposed
Method 309 in the proposed rule. The minimum rolling period is one day,
and the maximum rolling period is 30 days.
5. Handling and Storage of Waste
The proposed standards for handling and storage of waste would be
the same for all new and existing facilities. The proposed rule would
require that the handling and transfer of HAP-containing waste to or
from containers, tanks, vats, vessels, or piping systems be conducted
in such a manner that minimizes spills. In addition, all HAP-containing
waste would be stored in closed containers.
C. Compliance Dates
The proposed rule would require all existing sources to comply no
later than three years after the effective date of the standards. In
addition, the proposed rule adopts the compliance dates specified in
Sec. 63.6(b) and Sec. 63.6(c) of the General Provisions, 40 CFR part
63, subpart A.\3\
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\3\Ibid.
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D. Compliance Extensions
During development of the aerospace national emission standards for
hazardous air pollutants (NESHAP), the EPA received comments from the
regulated community regarding the process that would be used to comply
with the rule and certain difficulties that were anticipated,
particularly with the facilities' selection and approval of product
substitutions for coatings and hand-wipe cleaning solvents. Because of
the large number of product substitutions that may have to undergo
testing and qualification at each facility, some facilities may need to
request a compliance extension.
Section 63.6(i) of 40 CFR part 63 provides the requirements for
requesting an extension of compliance with a relevant standard
established under part 63.\4\ Specifically, Sec. 63.6(i)(4) allows the
issuance of a permit granting an extension of up to one year to comply
with the standard, if such additional period is necessary for the
installation of controls. Section 63.6(i)(4)(i)(B) requires requests
for compliance extensions to be submitted no later than 12 months
before the affected source's compliance date.
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\4\Ibid.
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The EPA is seeking comment on the significance of the potential
difficulties of complying with the proposed aerospace NESHAP in the
allotted 3 years (or 4 years if the one-year extension described above
is applied for and approved). In addition, the EPA is seeking comment
regarding how these difficulties can be addressed within the confines
of the statutory requirements of sections 112(d) and 112(i) of the Act.
Specifically, the EPA is seeking comment on what types of activities,
such as technical assistance, can be provided to assist sources
attempting to come into compliance with the aerospace NESHAP.
E. Compliance Testing and Monitoring
In addition to the specific testing and monitoring requirements
specified below for each affected source, the proposed rule adopts the
testing requirements specified in Sec. 63.7 of the General Provisions,
40 CFR part 63, subpart A.\5\
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\5\Ibid.
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1. Test Methods and Procedures
a. Cleaning operation. For multi-component cleaning solvents,
compliance with the proposed vapor pressure specifications would be
determined using E 260-85 to quantify the amount of each organic
compound in the cleaning solvent. The vapor pressure of each organic
compound would be determined from the manufacturer's data, standard
engineering reference texts, or other equivalent methods. The total
composite vapor pressure would then be calculated by summing the
partial vapor pressure of each component according to Raoult's Law.
For single component cleaning solvents, the EPA is proposing that
vapor pressure data supplied by the manufacturer of the cleaning
solvent, standard engineering reference texts, or other equivalent
methods be used for compliance determinations.
Owners or operators seeking to comply with the cleaning solvent
approved composition list would have to show compliance using data
supplied by the manufacturer of the cleaning solvent. The data must
identify all components of the cleaning solvent and demonstrate that
one of the approved composition definitions is met.
b. Primer and topcoat application operations. As noted earlier, the
proposed standards for organic HAP and VOC emissions would require
compliance with an equivalent organic HAP content level (pounds of
organic HAP per gallon of coating (less water) as applied) and an
equivalent VOC content level (pounds of VOC per gallon of coating (less
water and exempt solvents) as applied) for primers and for topcoats.
Compliance with these organic HAP and VOC content levels may be
accomplished by using compliant coatings, averaging between compliant
and non-compliant coatings, control devices, or any combination of
these methods. In addition, the proposed standards would require the
use of certain application techniques for the application of primers
and topcoats.
Test methods and procedures have been identified for compliance
with the organic HAP and VOC content levels. No test methods or
procedures have been identified for the application equipment
requirements; however, a test method has been identified for the
qualification of alternative application methods.
Method 24 in appendix A to 40 CFR part 60 would be used to
determine the VOC content of each primer and topcoat as applied.
Alternatively, manufacturer's data may be used to determine the VOC
content of these coatings. However, in the event of any inconsistency
between manufacturer's data and Method 24 test results, the Method 24
test results will take precedence.
The facility may rely on manufacturer's data to determine the
organic HAP content level of each coating. The total organic HAP weight
fraction and density of each coating as received would be determined
using the manufacturer's data. The volume of each primer and topcoat
used would be determined using company records. If diluent solvents or
other ingredients are added to a primer or topcoat prior to
application, then the total organic HAP and VOC weight fractions,
density, and volume must be adjusted appropriately to account for such
additions. These values would be required for each 24-hour period;
however, only changes in formulation would require re-determination of
total organic HAP and VOC weight fractions and density.
The proposed standards would then require the owner or operator to
calculate the volume-weighted average mass of both VOC and organic HAP
in coatings emitted per volume of coating (less water and exempt
solvents for VOC; less water for HAP) as applied. This calculation
would be performed for each 24-hour period.
If an owner or operator is seeking to comply by using compliant
coatings, the owner or operator would need to determine the organic HAP
content (less water as applied) and VOC content (less water and exempt
solvents as applied). If no changes in formulation as applied occurred,
then a re-calculation of the organic HAP and VOC content levels would
not be required. Where compliant coatings are used, the proposed rule
would require the determination of the organic HAP content using
manufacturer's data and VOC content using Method 24 or manufacturer's
data.
If a control device is used, the proposed standards require the
owner or operator to conduct an initial performance test to demonstrate
compliance with the overall control efficiency requirement of at least
81 percent. The percent reduction achieved by a control device may be
determined based either on total organic compounds (TOC) minus methane
and ethane or on total organic HAP.
For a carbon adsorber, the overall control efficiency would be
determined using a mass balance. The mass balance calculation would be
made every rolling period (the length of the rolling period will vary
from facility to facility and will range from 1 to 30 days).
For control devices other than carbon adsorbers, the overall
control efficiency would be based on capture efficiency and destruction
efficiency. Capture efficiency would be determined based on the
procedure specified in Sec. 52.741(a)(4)(iii) of 40 CFR subpart O,
unless the operation is performed within a total enclosure. An
enclosure that meets the requirements of a total enclosure as specified
in Sec. 52.741, appendix B, Procedure T of 40 CFR subpart O would have
a capture efficiency of 100 percent.
The destruction efficiency of a control device other than a carbon
adsorber would be determined using the following methods. Method 1 or
1A of 40 CFR part 60, appendix A, as appropriate, would be used for
selection of the sampling sites, and the gas volumetric flow rate would
be determined using Method 2, 2A, 2C, or 2D of 40 CFR part 60, appendix
A, as appropriate. Method 18 of 40 CFR part 60, appendix A, would then
be used to measure either TOC minus methane and ethane or total organic
HAP at the inlet and outlet of the control device. Also, any other test
methods or data that have been validated according to the applicable
procedures in Method 301 of 40 CFR part 63, appendix A, may be used.
The proposed standards would also allow the use of alternative
application methods provided that they generate organic HAP and VOC
emissions less than or equal to the emissions generated by HVLP or
electrostatic spray guns. The emission levels of the alternative
application method must be determined under actual production
conditions. This test would first involve determining the organic HAP
and VOC emissions for the 90-day period immediately preceding the
implementation of the alternative application method. During this
initial 90-day period, only HVLP or electrostatic spray guns would be
used. The alternative method would then be used on actual production
parts or assemblies for a period of time sufficient to coat an
equivalent amount of parts and assemblies as coated in the initial 90-
day period. Coatings used during the test period must be the same as
those used during the initial 90-day period. In addition, the dried
film thickness must be equivalent to that applied during the initial
90-day period.
The organic HAP and VOC emissions for the period of time where the
alternative method was used would then be calculated. Where the organic
HAP and VOC emissions after implementation of the alternative method
are less than or equal to the emissions for the initial 90-day period,
the alternative application method is in compliance.
The South Coast Air Quality Management District (SCAQMD), in
conjunction with the California Air Resources Board (CARB), is
currently developing a test protocol to measure the transfer efficiency
of spray application equipment. This test protocol would represent an
alternative method of qualifying application equipment for use under
the proposed standards. Since this test protocol is still under
development, the EPA is requesting comments from those familiar with
this test protocol or any other transfer efficiency laboratory test
method concerning the ability of these procedures to accurately and
repeatedly measure the transfer efficiency of spray application
equipment. In addition, the EPA is requesting comments on other methods
that may be used to measure the transfer efficiency of spray
application equipment.
c. Depainting. For the organic HAP emissions portion of the
proposed standards for depainting, the only test method or procedure
that would be required is the determination of the organic HAP content
of each chemical stripper. The proposed standards would require the use
of information supplied by the manufacturer to determine the organic
HAP content. If the organic HAP content of the chemical stripper cannot
be determined from manufacturer's data, then the owner or operator
would submit an alternative procedure for determining the organic HAP
content for approval by the Administrator.
For the annual limit on the gallons of organic HAP-containing
chemical stripper used for spot stripping and decal removal, the total
annual volume as applied of organic HAP-containing chemical stripper
and the number of aircraft depainted would be determined from company
records. The proposed standards would then require the owner or
operator to calculate the gallons of organic HAP-containing chemical
stripper used per aircraft. This calculation would be performed for
each annual period.
The proposed standards require inorganic HAP emissions from
depainting operations to be reduced by 99 percent using particulate
filters such as baghouses, cartridge filters, or dry filter media. The
EPA is proposing the use of Method 5 in appendix A to 40 CFR part 60 to
determine removal efficiency. The proposed standards would require
retesting whenever the particulate filter or supplier of the filter
media changes, or whenever modifications are made to the emission
collection system.
d. Chemical Milling Maskants. The same basic test methods and
procedures identified for primer and topcoat application operations are
also being proposed for chemical milling maskants, requiring the
determination of total organic HAP weight fraction, density, and volume
of chemical milling maskants as applied. Simpler procedures are being
proposed, as for primer and topcoat application operations, to
demonstrate compliance where only compliant chemical milling maskants
are being used.
As for primer and topcoat application operations, any control
device, including a carbon adsorber, used to control emissions from
chemical milling maskant application operations must have an overall
control efficiency of at least 81 percent and must control, except for
incidental emissions, all of the emissions from the maskant operation.
Test methods that would be used to determine the overall control
efficiency are identical to those given previously for primer and
topcoat application operations.
e. Handling and storage of waste. No test methods are being
proposed.
2. Monitoring Requirements
Monitoring is required by the proposed standards to determine
whether a source is in continuous compliance. This can be accomplished
by continuously measuring site-specific operating parameters, the
values of which are established by the owner or operator during the
initial compliance test. The operating parameter value is defined as
the minimum or maximum value established for a control device or
process parameter that, if achieved by itself or in combination with
other operating parameter values, determines that an owner or operator
is complying with the applicable emission limitation or standards. This
type of enhanced monitoring would be required for those emission points
for which the standards are expressed as a percent control. In
addition, the owner or operator is expected to install and operate the
equipment properly. For owners or operators complying with the proposed
standards for spray gun cleaning through the use of enclosed spray gun
cleaners, compliance would be demonstrated through recordkeeping (see
section II.F).
The proposed rule would require temperature to be monitored, using
a continuous recorder, for incinerators. For catalytic incinerators,
temperature monitors would be placed immediately before and after the
catalyst bed. For other incinerators, the temperature monitor would be
placed in the firebox or in the ductwork immediately downstream of the
firebox and before any substantial heat exchange occurs. All monitoring
equipment would be installed, calibrated, maintained, and operated
according to manufacturer's specifications.
Section 63.6(g) of 40 CFR part 63, subpart A, allows an owner or
operator of an affected source to request the use of alternative
methods of emission reduction for complying with design, equipment,
work practice, or operational emission standards, or combination
thereof, established under this part.6 Under the proposed rule, an
owner or operator of an affected source may also use control devices
other than those specifically identified in the proposed rule as a
means for achieving compliance with any portion of the rule. If devices
other than those identified are used, the proposed standards would
require the owner or operator to submit the parameters to be monitored
to the Administrator for approval.
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\6\Ibid.
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The proposed standards would require each owner or operator to
establish a range of values for each of these monitored parameters
during the initial performance test. As long as the control device is
operated within the established ranges, the proposed emission standards
are considered to be met. Consequently, exceedances of these parameters
would be considered a violation of the standards since operating the
control device outside of the parameters may reduce the efficiency of
the control device.
a. Cleaning operations. The proposed rule would require enclosed
spray gun cleaners to be visually inspected at least once per month for
leaks. The inspections would occur while the enclosed cleaner is in
operation.
b. Primer and topcoat application operations. Where an incinerator
or other control device is used to control organic HAP and VOC
emissions from primer and topcoat application operations, the
monitoring requirements specified above would be required.
For control of inorganic HAP emissions from primer and topcoat
application operations, the proposed standards would require that the
pressure drop across the particulate filters or waterwash be monitored
on a continuous basis.
c. Depainting. No monitoring requirements for organic HAP emissions
are being proposed. For inorganic HAP emissions, continuous monitoring
of the pressure drop across the filter, as for primers and topcoats, is
being proposed.
d. Chemical milling maskant application operations. Where a control
device is used to control organic HAP and VOC emissions from chemical
milling maskant application operations, the monitoring requirements
specified above would be required.
e. Handling and storage of waste. No monitoring requirements are
being proposed.
F. Recordkeeping and Reporting Requirements
The proposed rule proposes to adopt the requirements contained in
Sec. 63.9 (a) through (e) and Sec. 63.9 (h) through (j) and Sec. 63.10
(a), (b), (d), and (f) of 40 CFR part 63, subpart A.7 The proposed
rule, however, contains additional or clarifying elements and changes
certain time periods allowed for submitting or responding to certain
reports and requests required in Sec. 63.10. These elements and changes
are summarized below for each of the operations for which standards are
being proposed.
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\7\Ibid.
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1. Recordkeeping Requirements
a. Cleaning operations. For each cleaning solvent used at the
facility, the proposed rule would require a record of the name of the
cleaning solvent and documentation that shows the organic HAP
constituents of the cleaning solvent. For each cleaning solvent used in
hand-wipe cleaning operations that conforms to the approved composition
list, the records that would be maintained are the name of each
cleaning solvent, documentation demonstrating compliance to the
approved composition list, and annual purchasing records showing the
annual volume purchased of each. For each cleaning solvent used in
hand-wipe cleaning operations that does not conform to the approved
composition list but does conform to the vapor pressure requirement,
the information required to be recorded would be the name of each
cleaning solvent, the monthly usage of the cleaning solvent at each
operation, the composite vapor pressure, the manufacturer's data sheets
or other documentation of the vapor pressure, and any test reports and
calculations performed to determine the composite vapor pressure.
For cleaning solvents that do not conform to either the composition
or vapor pressure requirements and are used for the exempt cleaning
operations, daily records must be maintained of the name and volume of
each cleaning solvent at each operation at which it is used, and the
parts, assemblies, or subassemblies cleaned at these operations.
In addition, a record of all leaks from spray gun cleaners would be
kept, including source identification, the date that the leak was
discovered, and the date that the leak was repaired.
b. Primer and topcoat application operations. For all primers and
topcoats used at the facility, records must be maintained of the name
of each primer and topcoat and its organic HAP and VOC content as
received. In addition, the EPA is proposing different levels of
recordkeeping requirements depending on how the organic HAP and VOC
content levels are met. For primers or topcoats that are individually
compliant with the organic HAP and VOC content limits, records would be
required of the organic HAP and VOC content as applied, all data,
calculations, and test results (including Method 24 results taken
during an enforcement inspection) used in determining the organic HAP
and VOC contents as applied, and the monthly usage of each coating
formulation within each coating category.
If averaging among compliant and non-compliant coatings is used to
achieve compliance, then the proposed standards would require that up-
to-date records of daily volume-weighted average mass of organic HAP
and VOC contained in the coatings as applied be maintained. This
information would include all data and calculations used in determining
these daily values, such as manufacturer's data certifying the organic
HAP content of each coating as applied and Method 24 test results
(including those taken during an enforcement inspection) or
manufacturer's data that show the VOC content as applied.
If a control device is used to comply with the organic HAP or VOC
content limit for primers or topcoats, up-to-date records must be kept
on the control device. Each owner or operator would be required to keep
records of the equipment monitoring parameter measurements specified in
the proposed rule. For an incinerator other than a catalytic
incinerator, continuous records must be maintained of the firebox
temperature (or temperature in the ductwork immediately downstream of
the firebox). For a catalytic incinerator, continuous records must be
maintained of the gas stream temperature immediately before and after
the catalyst bed. For both types of incinerators, records must be
maintained of the overall control efficiency and all test results,
data, and calculations used in determining the overall control
efficiency.
For carbon adsorbers, records must be maintained of the overall
control efficiency, all test results, data, and calculations used in
determining the overall control efficiency, and the length of the
rolling material balance period and all of its supporting data and
calculations used to determine the rolling period.
For inorganic HAP emissions from primer and topcoat application
operations, either particulate filters or waterwash spray booths would
be used to achieve compliance. Records must be maintained of the
manufacturer's recommended limits for the pressure drop and readings of
the pressure drop across the filters or waterwash that are taken once
each shift during which the coating processes are in operation.
c. Depainting operation. Each owner or operator of a depainting
operation would be required to keep up-to-date records of the name of
each chemical stripper used, the organic HAP content of each stripper
and its supporting documentation, and the monthly volume usage of each
chemical stripper that contains organic HAP.
For non-chemical depainting methods, such as media blasting, owners
and operators would be required to maintain records of the type of non-
chemical-based equipment used and a description of any malfunctions
that occur. If a malfunction occurs, the information to be kept would
be the dates the malfunction occurred and was corrected, the methods
used to depaint the aerospace vehicles during the malfunction, and the
dates that these methods were begun and discontinued.
The proposed standards for depainting contains exemptions for parts
stripping, spot stripping, and decal removal, each of which requires
certain records to be maintained. For parts stripping, records must be
maintained for each model of aerospace vehicle of the parts normally
removed from the vehicle. For spot stripping and decal removal, annual
records must be maintained of the number of aircraft stripped, the
volume of organic HAP-containing chemical stripper used for spot
stripping and decal removal, the average number of gallons of organic
HAP-containing stripper used per aircraft, and all supporting data and
calculations.
For inorganic HAP emissions from depainting operations, either
particulate filters or baghouses (equipped with either bag or cartridge
filter media) would be used to achieve compliance. Records must be
maintained of the filter manufacturer's recommended pressure drop
limits and the readings of the pressure drop across the filter taken
once each shift during which the depainting process is in operation.
Also, records must be maintained of the particulate control efficiency
of each filter and all test results, data, and calculations used to
determine the control efficiency.
d. Chemical milling maskant application operation. The EPA is
proposing different levels of recordkeeping requirements depending on
how the organic HAP and VOC content levels are being met. For chemical
milling maskants that are individually compliant with the organic HAP
and VOC content levels, records of the volume-weighted average masses
of organic HAP and VOC emitted as applied must be kept. In addition,
all data and calculations used to determine these values and the
monthly volume of each chemical milling maskant formulation used each
month must be maintained.
If averaging among compliant and non-compliant chemical milling
maskants is used to achieve compliance, then the proposed standards
would require that up-to-date records of daily volume-weighted average
mass of organic HAP and VOC contained in the chemical milling maskants
as applied be maintained. This information would include all data and
calculations used in determining these daily values, such as
formulation data and Method 24 test results.
As for primer and topcoat application operations, if a control
device is used, up-to-date records must be kept on the control device.
Each owner or operator would be required to keep records of the
equipment monitoring parameter measurements specified in the proposed
rule. For an incinerator other than a catalytic incinerator, continuous
records must be maintained of the firebox temperature (or temperature
in the ductwork immediately downstream of the firebox). For a catalytic
incinerator, continuous records must be maintained of the gas stream
temperature immediately before and after the catalyst bed. For both
types of incinerators, records must be maintained of the overall
control efficiency and all test results, data, and calculations used in
determining the overall control efficiency.
For carbon adsorbers, records must be maintained of the overall
control efficiency, all test results, data, and calculations used in
determining the overall control efficiency, and the length of the
rolling material balance period and all of its supporting data and
calculations used to determine the rolling period.
e. Handling and storage of waste. Each owner or operator would be
required under the proposed standards to keep an up-to-date record of
each waste stream generated at the facility, identification of which
wastes are subject to RCRA and which are not, and documentation
supporting those determinations.
2. Reporting Requirements
The proposed rule would require four basic types of reports: (1)
Initial notification, (2) notification of compliance status, (3)
periodic reports, and (4) other reports. In addition, the proposed rule
would require that the results of any performance test required under
Sec. 63.7 of the General Provisions to 40 CFR part 63, subpart A, be
reported no later than 30 days after the completion of the test.8
A permit application as required under 40 CFR part 70 may be used in
lieu of the initial notification provided the same information is
contained in the permit application as required for the initial
notification.
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\8\Ibid.
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As stated above, the proposed standards adopt the reporting
requirements contained in Sec. 63.9(a) through Sec. 63.9(e) and
Sec. 63.9(h) through Sec. 63.9(j) and 63.10 (a), (b), (d), and (f) of
40 CFR part 63, subpart A. However, the time period allowed for the
Administrator to notify the owner or operator in writing of approval or
disapproval of the request for an adjustment to a particular time
period or postmark deadline submitted under Sec. 63.9(i) has been
changed to within 30 calendar days of receiving sufficient information
to evaluate the request, rather than 15 calendar days as provided for
in Sec. 63.9(i)(3).
Sections 40 CFR 63.9 and 63.10 of the General Provisions identify
the type of generic information to be included in the initial
notification, notification of compliance status, and other reports and,
therefore, this information is not repeated in this preamble. The
following paragraphs summarize the additional information specific to
the aerospace rule that should be included in the notification of
compliance status and the type of information to be included in the
periodic reports.
a. Cleaning operation. The notification of compliance status should
include an identification of each cleaning solvent used at the
facility, a description of the procedures to be used to ensure that
bags and containers are kept closed when not in use and that cleaning
solvents are stored in closed containers, the name of each cleaning
solvent that does not conform to the approved composition list, and the
vapor pressure test results of each.
Specific to spray gun cleaning, the notification of compliance
status should also contain a detailed description of all methods used
to clean spray guns and an explanation as to how each cleaning method
complies with the proposed standards.
Information to be included in the semiannual report covers all
noncompliance situations such as using a hand-wipe cleaning solvent
that does not conform to the approved composition list or vapor
pressure requirements used in a non-exempt operation. In addition, the
semiannual report includes information on new cleaning solvents used
for hand-wipe cleaning in the previous six months, as well as
previously reported cleaning solvents no longer in use. The information
to be provided is a list of any new cleaning solvents used in the
previous six months, a list of new non-HAP cleaning solvents, if any,
used, and, for new cleaning solvents used in hand-wipe cleaning
operations, the composite vapor pressure of each.
If the cleaning operation has been in compliance for the annual
period, then an annual report would be required occurring every 12
months from the date of the initial report stating that the cleaning
operation has been in compliance with the applicable standards.
b. Primer, topcoat, and chemical milling maskant application
operations. For primer, topcoat, and chemical milling maskant
application operations, the notification of compliance status should
identify the combination of compliant coatings, averaging, and control
devices that were used to demonstrate that the facility was in
compliance, and, for control devices, what operating parameters were
identified for continuous monitoring in order to ensure continuous
compliance with the proposed standards.
Owners and operators complying with the organic HAP and VOC content
levels for primer, topcoat, and chemical milling maskant application
operations would be required to report each exceedance of the organic
HAP or VOC content level, as well as any time a primer or topcoat
application operation was not immediately shut down when the pressure
drop across the filters or waterwash was out of range. These reports
would be submitted on a semiannual basis.
If control devices are used, semiannual reports would be required
that contain information on all days when the average values of the
parameters required to be monitored were outside the ranges established
in the operating permit.
For incinerators, this would be whenever each 3-hour average
temperature was below the average temperature established during the
most recent performance test during which compliance was demonstrated.
If no exceedances occur, each owner and operator would submit
annual statements indicating that each affected facility has been in
compliance. The annual reports for primer and topcoat application
operations would also identify the number of times, if any, the
pressure drop limits for each filter or waterwash system were exceeded.
c. Depainting operation. The notification of compliance status for
depainting operations should identify each chemical stripper used at
the facility to depaint aerospace vehicles and the organic HAP content
of each. Each chemical stripper that contains organic HAP and is used
for decal removal, depainting of parts, and spot stripping would also
be identified. In addition, the types of non-chemical depainting
methods and techniques used at the facility and the manufacturer's
recommended pressure drop across the filters for the particulate
removal system, if applicable, would be identified. Finally, each owner
or operator would be required to describe the depainting methods to be
used during periods of malfunction of the non-chemical depainting
methods.
Information to be included in the semiannual report would include
the name of any new chemical strippers used during the previous six
months and the organic HAP content of each. For each chemical stripper
used for depainting operations that undergoes reformulation, its
organic HAP content after reformulation would be submitted with the
semiannual report. The report would also be required if the owner or
operator used any new non-chemical depainting technique at the facility
since the initial report or any subsequent semiannual report. The
semiannual report would be required to identify each 24-hour period
where organic HAP were emitted from the depainting operation except
from the exempt operations, any periods of malfunction of non-chemical
depainting methods and techniques, and any periods where the non-
chemical depainting operation was not immediately shut down when the
pressure drop across the filters was out of range. For each malfunction
that occurs, the following information would be reported: (1) The piece
of equipment that malfunctioned, (2) the date the malfunction occurred
and the date it was corrected, (3) a description of the malfunction,
(4) the alternate methods used to depaint the aerospace vehicles during
the malfunction period, and (5) the dates that these methods were begun
and discontinued.
Finally, the semiannual report would be required to identify all
changes in the type of aircraft depainted at the facility and to
identify the parts normally removed for depainting separate from the
aircraft for each new type of aircraft depainted.
For spot stripping and decal removal, an annual report would be
required whenever the average volume per aircraft of organic HAP-
containing chemical strippers used exceeds the limits specified in the
proposed rule for the annual period.
If the depainting operation has been in compliance for the annual
period, then an annual report would be required every 12 months from
the date of the initial report stating that the depainting operation
has been in compliance with the applicable standards. This annual
report would also detail how many times the pressure drop limits for
each filter system were exceeded and report when the calculated annual
average volume of organic HAP-containing strippers used per aircraft
for spot stripping and decal removal exceeded the applicable limits.
d. Handling and storage of waste. The notification of compliance
status would identify each waste stream and identify whether it is RCRA
or non-RCRA regulated. The notification would also include a
description of the procedures to be used to ensure that spills are
minimized during handling and transfer operations. Also included would
be the procedures to be used to ensure that waste is stored in closed
containers.
Semiannual reports are required to identify any waste stream whose
RCRA or non-RCRA classification has changed. The semiannual report
would also identify any new waste streams and whether each is RCRA or
non-RCRA regulated. An annual report would be required if no changes
occurred in the RCRA status to the existing waste streams and if no new
waste streams were generated.
III. Summary of Environmental, Energy, and Economic Impacts of the
Proposed Standards
A. Emission Reductions
1. Existing Facilities
For the existing aerospace OEM and rework facilities (approximately
2,869 facilities in the base year 1991), the nationwide baseline HAP
emissions are estimated to be 189,000 Mg/yr (208,000 tpy).
Implementation of the proposed regulation would reduce these emissions
by approximately 112,600 Mg/yr (123,700 tpy), or 59 percent.
2. New Facilities
For the aerospace industry, no net growth is expected over the next
five years; therefore, no net emission reduction due to new facilities
is anticipated during this period.
B. Secondary Environmental Impacts
Secondary environmental impacts are considered to be any air,
water, or solid waste impacts, positive or negative, associated with
the implementation of the proposed standards. These impacts are
exclusive of the direct air emission reductions discussed in the
previous section. All of the impacts discussed below reflect the
maximum increase or decrease, as appropriate, that would occur if all
of the affected sources converted to the control option described.
Some product reformulations that may be used to comply with the
proposed standards for hand-wipe cleaning, primers, and topcoats may
contain organic HAP or VOC not present in the original product. In
these cases, different organic HAP or VOC may be emitted as a result of
the proposed rule, but the overall level of these compounds that are
emitted will decrease. Chemical strippers that do not contain organic
HAP used for depainting may result in increased VOC emissions when used
to replace methylene chloride-based chemical strippers (methylene
chloride is a HAP, but not a VOC).
There is a potential for an impact on water quality resulting from
some of the prescribed control measures. Under baseline conditions for
chemical milling maskant operations, no wastewater is generated;
however, some of the sources may install a carbon adsorber to control
solvent emissions. If all affected sources use carbon adsorbers, the
amount of water needed to create regenerating steam for these systems,
which will add to the wastewater burden from these sources, is
estimated to be 447 million gallons per year nationwide. For depainting
operations, there are two options available for meeting the proposed
rule, both of which will result in a decrease in the amount of
wastewater generated compared to baseline, which is 251 million gallons
per year. The decrease in wastewater nationwide is estimated to be 251
million gallons and 86 million gallons if all affected sources use dry
media blasting or chemical strippers that do not contain organic HAP,
respectively.
Sources installing a carbon adsorption system on their chemical
milling maskant operations would generate additional solid waste due to
the necessity of periodically disposing of spent activated carbon. If
all affected sources use carbon adsorbers, this added nationwide solid
waste burden is estimated to be 4,500 tons per year, compared to the
baseline of 21,200 tons per year. Rework facilities that presently use
a methylene chloride-based paint stripper must dispose of 3,469 tons
per year of paint/solvent sludge created by depainting. A total
conversion to dry media paint removal would produce an increase in the
amount of solid waste composed of dry paint chips and spent blasting
media. This increase in solid waste is estimated to be 13,280 tons per
year on a nationwide basis. The proposed standards for the control of
inorganic HAP emissions from primer and topcoat application operations
would result in the increase in solid waste generation from the
disposal of used dry filter media. The increased solid waste burden is
estimated to be 640 tons per year, compared to the baseline solid waste
generation of 3,540 tons per year.
C. Energy Impacts
Some of the control measures proposed for aerospace manufacturing
and rework operations would lead to increases in energy consumption.
Both of the control options for chemical milling maskant operations,
operation of a carbon adsorber or conversion to waterborne chemical
milling maskant, would involve increased electricity usage (waterborne
chemical milling maskants must be cured at elevated temperatures). The
total additional energy needed if all affected sources operate new
carbon adsorbers is estimated to be 1.7 billion kilowatt-hours (kWh)
per year, and the energy increase for all affected sources to operate
new curing ovens for waterborne chemical milling maskants is estimated
at 324,700 kWh per year. Baseline energy consumption for chemical
milling maskant operations is considered to be negligible since the use
of solvent-based chemical milling maskants does not directly require
the use of electricity.
The dry media paint removal systems that would be installed at
rework facilities consume additional energy compared to the solvent
stripping method. Baseline energy consumption for solvent stripping is
considered to be negligible since the use of these strippers does not
directly require the use of electricity. The increase in energy
consumption involved in operating dry media blasting systems is
estimated to be 51 million kWh per year. The use of chemical strippers
that do not contain organic HAP is essentially the same as the baseline
solvent stripping operation; therefore, no energy impact will result
from their use.
The proposed standards for the control of inorganic HAP emissions
from primer and topcoat application operations would require some
facilities to install additional spray booths. These spray booths,
whether equipped with dry filters or waterwash, will increase the
energy consumption of the affected sources. This increase in energy
consumption is estimated to be 5.9 million kWh per year, compared to
the baseline energy consumption of 117.4 million kWh per year.
D. Cost Impacts
The total capital and annualized control costs (1992 dollars),
including recovery credits, attributable to compliance with the
proposed standards have been estimated for both existing and new
facilities. The following two subsections summarize the results of this
cost analysis.
1. Existing Facilities
a. Capital costs. Capital costs would be incurred with the
implementation of control measures for chemical milling maskants (both
solvent-based chemical milling maskants with a carbon adsorber and
waterborne chemical milling maskants), dry media blasting for
depainting, spray gun cleaning, and control of HAP emissions from
primer, topcoat, and depainting operations. With the exception of dry
media blasting for depainting, the nationwide capital costs listed
below represent the maximum costs that would be incurred assuming that
all facilities implemented the specific control option. For dry media
blasting, it is not reasonable to assume that all commercial and
military rework facilities (a total of 2,026 facilities) depaint the
outer surface of aerospace vehicles. Therefore, it was assumed that
only 5 percent of the small and medium size rework facilities and all
of the large rework facilities perform outer surface depainting.
For carbon adsorbers used in conjunction with solvent-based
chemical milling maskants, the nationwide capital cost is estimated to
be $500 million, and for waterborne chemical milling maskants it is
estimated to be $289 million. The implementation of dry media blasting
systems for depainting would require a nationwide capital cost of $61
million. It should be noted that other control measures exist for
depainting other than dry media blasting, such as chemical strippers
that do not contain organic HAP, that require no capital investment.
Selection of chemical strippers that do not contain organic HAP by all
affected sources instead of dry media blasting would decrease the total
nationwide capital investment by approximately 10 percent. The proposed
rule would also require capital costs for high transfer efficiency
application equipment and spray gun cleaning equipment totalling $130
million and $10 million, respectively. The control of inorganic HAP
emissions from primer and topcoat application operations would require
the installation of spray booths and filter systems at a capital cost
of $13 million.
Total nationwide capital costs range from $503 million to $714
million, depending on which chemical milling maskant control option is
used.
b. Annual costs. All of the control options will result in some
annual costs being incurred by the affected sources. However, the
annualized cost figures presented below reflect the net cost to
implement the control options after taking into account the costs that
would have been incurred for baseline. This net cost (MACT cost minus
baseline cost) resulted in net annual savings for primers, topcoats,
and high transfer efficiency application methods; spray gun cleaning;
and the use of chemical strippers that do not contain organic HAP. All
other options resulted in net annual costs to the affected sources. The
net cost (or savings) for all control options reflects the maximum cost
(or savings) that would be incurred assuming all affected sources
implemented the specific control option.
Only one cost analysis was completed for primers, topcoats, and
high transfer efficiency application methods due to the
interrelationship between these operations. For example, high transfer
efficiency application methods will result in a lower volume of primers
and topcoats being applied. In addition, the organic HAP and VOC limits
on primers and topcoats will, due to higher solids content, also result
in a lower volume of the coatings being applied. The reduction in
coating usage due to the lower organic HAP and VOC content had to be
taken into account first, then the reduction in coating usage due to
high transfer efficiency application methods was applied to this
reduced coating volume to obtain the true overall reduction in coating
usage. After factoring in the annualized cost of the coating equipment,
the analysis showed a nationwide savings of $71 million for commercial
sources and $18 million for military sources.
The savings for primers, topcoats, and high transfer efficiency
application methods are due primarily to labor savings that would
result from the reduced volume of coatings to be applied. For example,
if it would have taken 15 gallons of primer under baseline conditions
to coat an aircraft and only 12 gallons under MACT conditions, then the
cost analysis assumes a labor savings for the 3 gallons of primer that
were not applied. The EPA has received some evidence, however, that the
labor stays the same or may even increase with the use of high transfer
efficiency application methods (specifically HVLP spray guns). The EPA
requests comments from facilities that have converted from conventional
spray guns to HVLP spray guns regarding the labor hours per gallon of
coating applied for each application method.
For spray gun cleaning, the proposed standards would result in a
nationwide savings of approximately $56 million. This is due primarily
to reduced solvent usage and associated spent solvent disposal.
The use of chemical strippers that do not contain organic HAP would
result in a nationwide savings of approximately $2 million. While the
cost of non-HAP strippers is generally higher than the cost of
conventional strippers, this cost is offset by the reduced disposal
costs incurred with non-HAP strippers. Since non-HAP strippers do not
contain methylene chloride, they can typically be treated on-site. This
eliminates the disposal costs incurred with the conventional strippers,
which are typically shipped off-site for disposal.
Nationwide annual costs are estimated to be $14 million for hand-
wipe and flush cleaning, $111 million for waterborne chemical milling
maskants, $2 million for inorganic HAP emissions from primer and
topcoat application operations, and $0.3 million for inorganic HAP
emissions from blast depainting operations.
Total nationwide costs, taking into account both the savings and
costs detailed above, are estimated to be a savings of $20 million.
Sources subject to the proposed rule would be required to perform
certain monitoring, recordkeeping, and reporting tasks. These
information collection requirements will create a burden on the
affected sources in terms of resources needed to comply with these
requirements (see section VI.D.). The total nationwide costs of the
manpower requirements to complete these tasks are estimated to be $36.7
million.
Total nationwide costs are estimated to be $16.7 million, which is
the sum of the annualized costs (a total nationwide savings of $20
million) and the costs due to monitoring, recordkeeping, and reporting
requirements (a total nationwide cost of $36.7 million).
2. New Facilities
For the aerospace industry, no net growth is expected over the next
five years; therefore, no net costs (or savings) due to new facilities
are anticipated during this period.
E. Economic Impacts
Due to the low total compliance costs associated with the proposed
regulation, the discussion of the economic impacts is presented in a
qualitative manner. The low costs of the proposed regulation are in a
large part due to cost savings expected to be achieved by some model
plants. The economic impact analysis discussed in a qualitative manner
the primary impacts (the direction of price and output changes in the
aerospace industry), as well as secondary impacts (the direction of
changes in the demands for inputs such as coatings) associated with the
proposed regulation.
Cost estimates indicate that the total annual compliance costs are
approximately $16.7 million. In 1990, revenue for this industry
equalled approximately $118.9 billion. Using revenue data as a proxy
for production costs, the costs of the proposed regulation are only
0.01 percent of the total production costs for the industry. This
increase in production cost is expected to have minimal impact on the
current prices and outputs of the aerospace industry.
Secondary impacts refer to changes in factor demand by all
aerospace producers. For example, while the primary impact of the
regulation on spray gun cleaning is a decrease in the cost of
performing this task, the actual cause of the decrease in the cost is a
reduction in the use of methyl ethyl ketone and other solvents.
Although compliance with the proposed regulation is expected to reduce
consumption of coatings and solvents in general and, therefore,
negatively impact the producers of these products, compliance with the
proposed regulation is also expected to increase product substitution
so that demand for non-HAP strippers, waterborne maskants, and low
vapor pressure solvents will increase. Lack of economic data on a
product-specific basis prevents quantification of the indicated
impacts.
IV. Process Descriptions and Control Technologies
A. Process Descriptions
Aerospace manufacturing and rework operations consist of the
following basic operations: Chemical milling maskant application,
chemical milling, adhesive bonding, cleaning (e.g., hand-wipe, spray
equipment, and flush), metal finishing, electrodeposition, coating
application (e.g., primers, topcoats, sealants, and specialty
coatings), depainting, and composite processing. In addition, most
aerospace manufacturing and rework facilities generate waste and
wastewater, and some facilities have storage tanks for hand-wipe
cleaning solvents. An aerospace facility may conduct all of these
processes in its operations, such as an OEM facility that produces the
entire aircraft. However, an aerospace facility may conduct only a
subset of these operations, such as a facility that produces a single
component or assembly, or a facility that provides a service such as
chemical milling.
1. Chemical Milling Maskant Application and Chemical Milling
Chemical milling uses etchant solutions to reduce the thickness of
selected areas of metal parts in order to reduce weight. The process is
typically used when the size or shape of the part precludes mechanical
milling or when chemical milling is advantageous due to shorter
processing time or its batch capability.
Chemical milling maskants are typically rubber- or polymeric-based
coatings applied to an entire part or subassembly by brushing, dipping,
spraying, or flow coating. After the chemical milling maskant is cured,
it is removed from selected areas of the part where metal is to be
removed during the chemical milling process. The chemical milling
maskant remaining on the part protects those areas from the etchant
solution. Chemical milling maskants typically contain either a toluene/
xylene mixture or perchloroethylene as its solvent constituents.
Organic HAP emissions occur through evaporation of the solvent as
the chemical milling maskant is applied and while it cures.
2. Adhesive Bonding (Adhesives and Adhesive Bonding Primers)
Adhesive bonding involves the joining together of two or more metal
parts, such as the parts of a honeycomb core. This process is typically
performed when the joints being formed are essential to the structural
integrity of the aircraft. The surfaces to be bonded are first coated
with an adhesive bonding primer to promote adhesion and protect from
subsequent corrosion. Structural adhesives are applied as either a thin
film or as a paste, and can be oven cured or cured in an autoclave.
Organic HAP emissions occur from the evaporation of solvents contained
in the adhesive bonding primer and adhesive during their application,
as well as during the curing step.
3. Cleaning Operations
a. Hand-wipe and flush cleaning. Aerospace components are cleaned
frequently during manufacturing to remove contaminants such as dirt,
grease, and oil, and to prepare the components for the next operation.
Cleaning is typically performed by a hand wiping process using a wide
variety of cleaning solvents. Assemblies and parts with concealed or
inaccessible areas may be flush cleaned by pouring the cleaning solvent
over or into the part. The cleaning solvent is then drained from the
part and the procedure is repeated as many times as necessary to ensure
the required cleanliness.
Organic HAP emissions from hand-wipe and flush cleaning operations
occur from the evaporation of cleaning solvents during the cleaning
process, including evaporation of the solvent from open containers and
from solvent-soaked cloth and paper. Organic HAP emissions also occur
from storage tanks used to store cleaning solvents.
b. Spray gun cleaning. Spray guns and other components of coating
units must be cleaned when switching from one coating to another and
when they are not going to be immediately reused. The cleaning of spray
guns can be performed either manually or with enclosed spray gun
cleaners. Manual cleaning involves disassembling the gun and placing
the parts in a vat containing an appropriate cleaning solvent. The
residual paint is brushed or wiped off the parts. After reassembling,
the cleaning solvent may be sprayed through the gun for a final
cleaning.
Enclosed spray gun cleaners are self-contained units that pump the
cleaning solvent through the gun within a closed chamber. After the
cleaning cycle is complete, the guns are removed from the chamber and
typically undergo some manual cleaning to remove coating residue from
areas not exposed to the cleaning solvent, such as the seals under the
atomizing cap.
Organic HAP emissions from spray gun cleaning occur from the
evaporation of cleaning solvents during the cleaning cycle, such as
while hand cleaning the guns in an open vat. Organic HAP emissions also
occur from enclosed spray gun cleaners when they are opened to remove
the guns.
4. Metal Finishing and Electrodeposition
Metal finishing processes are used to prepare the surface of a part
for better adhesion, improved surface hardness, and improved corrosion
resistance. Typical metal finishing operations include conversion
coating, anodizing, desmutting, descaling, and any operation that
chemically affects the surface layer of a part.
Electrodeposition, or metal plating, is an additive process for
metal substrates in which another metal layer is added to the substrate
in order to enhance corrosion and wear resistance necessary for the
successful performance of the component. The two types of
electrodeposition typically used are electroplating and plasma arc
spraying.
HAP emissions from metal finishing operations occur in the form of
gases or vapors that evaporate from the surface of processing
solutions. Evaporation of solution also occurs from the parts as they
are removed from the processing tanks.
5. Coating Application
A coating is a material that is applied to the surface of a part to
form a decorative or functional solid film. The most common coatings
are the broad categories of non-specialized primers and topcoats. There
are also numerous specialty coatings ranging from temporary protective
coatings to radiation effect coatings designed to shield aircraft from
radar detection.
Coatings are applied to aerospace vehicles and components using
several methods of application. The methods most commonly used are
spraying, brushing, rolling, flow coating, and dipping. Spray
application systems include conventional air spray, airless spray, air-
assisted airless, electrostatic, and high volume low pressure (HVLP)
spray. These latter two methods are generally accepted as having better
transfer efficiency than other spraying methods and are gaining
increased use as a means of using less coating and, hence, reducing
emissions.
Nearly all aerospace coatings contain a mixture of organic
solvents. Organic HAP emissions from coating application occur from the
evaporation of the solvents during mixing, application, and drying.
Inorganic HAP emissions of metal compounds (e.g., chromium and cadmium)
also occur from overspray, which is exhausted from spray booths or
paint spray hangars.
6. Depainting
The depainting operation involves the removal of coatings from the
outer surface of aircraft. The two basic depainting methods are
chemical depainting and blast depainting. Chemical depainting agents
are applied to the aircraft, allowed to degrade the coating, and then
scraped or washed off with the coating residue. Blast depainting
methods utilize a media such as plastic, wheat starch, carbon dioxide,
or high pressure water to remove coatings by physically abrading the
coatings from the surface of the aircraft.
Organic HAP emissions from chemical depainting occur from
evaporation of the solvents in the stripping solution. The amount of
emissions from the process is directly related to the surface area
being stripped, the type and thickness of coating to be removed, and
the effectiveness of the stripper. Inorganic HAP emissions occur from
the various blast depainting methods. The inorganic HAP are contained
in the coatings being removed (trace amounts of inorganic HAP may also
be found in some blast media) and are emitted as particulates.
7. Composite Processing
Composite processing consists of seven basic operations: Layup,
thermal forming, debulking, curing, break-out, compression molding, and
injection molding. Layup is the process of assembling the layers of the
composite structure by positioning composite material in a mold and
impregnating the material with a resin. Thermal forming is the process
of forming the layup in a mold, which usually takes place in an
autoclave. During the thermal forming process, debulking also may
occur, which is the simultaneous application of low-level heat and
pressure to the composite structure to force out excess resin, trapped
air, vapor, and volatiles from between the layers of the composite
structure. The curing step, which is the process of changing the resin
into a solid material through a polymerization reaction, also occurs in
the autoclave. After curing and removal from the autoclave, the break-
out process removes the composite structure from the molds or curing
fixtures.
Two other methods of forming composite structures are compression
molding and injection molding. Compression molding is the process of
filling one half of a mold with a molding compound, closing the mold,
and applying heat and pressure until the material is cured. Injection
molding uses a closed mold, where the molding compound is injected into
the mold, maintained under pressure, and then cured by applying heat.
Organic HAP emissions from composite processing occur from
volatilization of a small portion of the solvent components during
curing, because the majority of these solvents are consumed in the
curing reaction of the resin.
8. Wastewater
Nearly every aerospace manufacturing and rework operation has the
potential to generate wastewater. For example, metal finishing
operations use water to rinse parts after each processing step. These
rinse steps are typically carried out in large tanks with either a
continuous or intermittent water flow. The wastewater generated is
usually treated to some extent at the facility, then discharged.
HAP emissions from wastewater result from the evaporation of
volatile components in the water. Evaporation may occur in open
trenches, storage tanks, and treatment operations.
9. Handling and Storage of Waste
Waste is produced primarily from cleaning, coating, and depainting
operations. Cleaning operations produce solvent laden cloth and paper
and spent solvent which can emit organic HAP from the evaporation of
the solvents. Coating operations produce waste paint and waste solvent
thinner that also emit organic HAP through evaporation. Depainting
operations can produce either a liquid or solid waste stream depending
on the type of process used. Chemical depainting processes produce a
liquid sludge that consists of the stripper solution and paint residue.
Emissions occur from the evaporation of the solvent from the stripper
solution. Blast depainting processes produce a solid waste stream that
consists of paint chips and spent blasting media. Emissions do not
directly occur from this waste stream, although particulate emissions
are generated during the blasting process.
10. Storage of Hand-Wipe Cleaning Solvents
Many large aerospace facilities use storage tanks for hand-wipe
cleaning solvents. According to data obtained through responses to EPA
questionnaires under section 114 of the Act (section 114
questionnaires), these tanks are primarily above ground, fixed-roof
type ranging in size from 350 to 6800 gallons in size. Emissions from
these tanks occur from evaporation of the cleaning solvents, as well as
breathing and working losses.
B. Control Techniques
The principal techniques used by the aerospace industry to control
organic HAP emissions are preventative measures and control devices.
For the control of inorganic emissions, control devices such as filters
and waterwash are used. Preventative measures are any action, product
modification, process modification, or equipment change designed to
eliminate or reduce the generation of emissions. Control devices do not
prevent the generation of emissions, but rather capture or destroy the
emissions generated by a source.
Preventative measures are usually the most desirable method to
reduce emissions since they eliminate or reduce the actual generation
of pollutants. Typically, the emission reduction is obtained using less
energy and producing less waste than using a control device to achieve
the same emission reductions. Preventative measures used by the
industry are: (1) Product reformulations that replace products
containing high levels of HAP and VOC with products containing less HAP
and VOC or that eliminate the HAP or VOC content completely, such as
chemical strippers that contain no organic HAP for depainting; (2)
product reformulations, such as higher solids content coatings, that
reduce the amount of the HAP- and VOC-containing product used; (3)
equipment changes that result in emission reductions, such as replacing
conventional spray guns with HVLP spray guns; and (4) work practice
standards, such as housekeeping.
Control devices are typically used where product reformulation is
not feasible or where the concentration of the exhaust stream is
sufficiently high to warrant their use. Control devices may destroy the
HAP and VOC, as with an incinerator, or capture the HAP and VOC, as
with a carbon adsorber. Often, the compounds captured by a control
device can be recovered for reuse. Control devices in predominant use
by the industry for the reduction of organic HAP emissions are: (1)
Carbon adsorbers, (2) incinerators, and (3) ultraviolet oxidation.
Activated carbon fiber adsorbents to concentrate VOC emissions are
frequently used in conjunction with incinerators. For inorganic HAP
particulate emissions, reduction is achieved predominantly through the
use of filtration devices.
1. Preventative Measures
a. Product reformulation. HAP and VOC emissions may be controlled
by replacing products containing high concentrations of HAP and VOC
with ones that have reduced or eliminated HAP and VOC entirely. Each
individual facility must evaluate the ability of the new product to
maintain standards of quality and performance. In addition, the
potential overall environmental benefit of the reformulated products
must be carefully evaluated.
(1) Product reformulation--coatings. Product reformulations for
coatings can be generally classified as waterborne, higher solids,
powder, and self-priming topcoats. Each category is discussed below.
(a) Waterborne coatings. Waterborne coatings utilize a resin system
that is dispersible in water. A portion of the organic solvent is then
replaced with water. The organic solvent may be 5 to 40 percent by
weight of the waterborne coating, compared to a conventional organic
solvent-based coating containing as much as 80 percent by weight
solvent.
In addition to the lower solvent content, waterborne coatings have
other advantages over solvent-based coatings. Less overspray and
improved spray transfer efficiency may be achieved with waterborne
coatings than with conventional coatings that utilize solvents with a
density less than that of water. Additionally, because of the reduced
solvent content, waterborne coatings may be less toxic and present a
reduced fire hazard.
Waterborne coatings have limitations such as requiring spray guns
with specific materials of construction, protection from freezing, and
better control of temperature and humidity during application. In
addition, waterborne coatings generally require longer drying times,
are more sensitive to substrate material and cleanliness, and have
lower salt spray resistance.
(b) Higher solids. Higher solids coatings are solvent-based coating
formulations that have been modified to lower the solvent-to-solids
ratio. The coatings usually contain 50 to 65 percent by volume solids,
compared to conventional solvent-based coatings that may contain up to
40 percent by volume solids. The increased solids content gives greater
surface area coverage per gallon of coating, which reduces the total
volume of coating required. Consequently, solvent emissions are also
reduced when higher solids coatings are used to apply the same volume
of solids that are applied with a conventional solvent-based coating.
Higher solids coatings generally have higher viscosities and longer
drying times than conventional solvent-based coatings. The higher
viscosity tends to make spray application more difficult because it is
harder to control gloss and film thickness, and may require the coating
to be heated before application. Higher solids coatings typically are
not used as dip coatings due to the difficulty in maintaining a uniform
dispersion of solids in the dip tank.
(c) Powder. Powder coatings are a class of coatings applied
electrostatically in dry form and then baked to cure. The coatings
consist of fine, dry particles of paint solids. During the curing step,
the particles fuse to create a continuous film. Use of powder coatings
requires that the substrate must be able to withstand the high
temperatures (typically greater than 121 deg.C (250 deg.F) and
frequently greater than 177 deg.C (350 deg.F)) necessary to cure the
paint.
The major advantage of using powder coatings is greatly reduced
solvent emissions. The lack of a solvent base also reduces fire hazard,
toxicity, and the make-up air requirements of the spray booth.
Powder coatings must be applied electrostatically, so they cannot
be used on non-conductive parts such as composites. Other reported
disadvantages of powder coatings are the difficulty in obtaining a high
quality appearance, production must be shut down for color changes, the
powder must remain dry at all times prior to application, and higher
energy costs. As noted above, the high curing temperatures of powder
coatings precludes their use on temperature-sensitive substrates.
(d) Self-priming topcoats. Self-priming topcoats eliminate the need
to apply a primer coat between the substrate and the topcoat. Self-
priming topcoats have the adhesion and corrosion characteristics of a
conventional primer and the environmental resistance and functional
fluid resistance of a conventional topcoat. These coatings also
eliminate the need for chrome-containing primers.
(2) Product reformulation--hand-wipe cleaning solvents. Product
reformulations for hand-wipe cleaning that are prevalent in the
aerospace industry can be classified as aqueous, hydrocarbon-based, and
non-chemical. Each category is discussed below:
(a) Aqueous. Aqueous cleaners contain at least 80 percent water,
are non-flammable and non-combustible, and are completely soluble in
water. Other components may include corrosion inhibitors, alkalinity
builders, organic surfactants, and bioenzyme mixtures and nutrients
depending on the desired soil removal properties. Aqueous cleaners have
been used in non-critical areas where strict cleanliness requirements
do not have to be met, or where there are no confined spaces that may
trap residues of the cleaner.
(b) Hydrocarbon-Based. Hydrocarbon-based cleaners are nonsemi-
aqueous cleaners that are composed of a mixture of hydrocarbons and
oxygenated hydrocarbons. These cleaners have a maximum vapor pressure
of 7 mm Hg at 20 deg.C (3.75 in. H2O at 68 deg.F) and contain no
HAP or ozone depleting compounds.
(c) Non-chemical. Several aerospace facilities have demonstrated
the viability of using non-chemical methods such as dry media blasting
for cleaning operations. These methods are typically used to remove
dry, scale-like deposits such as carbon residue on engine components.
Dry media blasting can usually be used only on components that can
withstand the force of blasting without deformation.
b. Equipment changes. The aerospace industry has implemented
several equipment changes that directly reduce the level of HAP
emissions. While there are equipment changes that affect emissions from
every process, the three changes predominantly used in the industry are
high transfer efficiency spray guns, enclosed spray gun cleaners, and
proportional paint mixers. Each of these equipment changes are
discussed below.
(1) High transfer efficiency spray guns. Emissions from spray
coating operations can be reduced through the use of spraying systems
with higher transfer efficiency than conventional spray guns. Transfer
efficiency, expressed as a percentage, can be defined as the ratio of
coating solids actually applied to the surface of the component being
coated to the amount of solids released from the spray gun. Spraying
systems with a higher transfer efficiency can coat the same surface
area using less coating. Therefore, the HAP emissions resulting from
the use of this equipment are reduced compared to applying the same
coating with conventional spray equipment.
High volume low pressure (HVLP) and electrostatic spraying systems
are the primary high efficiency spray methods used by the industry.
HVLP spray guns use high volumes (10 to 25 standard cubic feet per
minute (scfm)) of low pressure (2 to 10 pounds per square inch gauge
(psig)) air to deliver the paint. The lower air pressure creates a
lower particle speed, resulting in a more controlled spray pattern with
less overspray and bounce back from the substrate. With electrostatic
spray systems, atomized particles of coating acquire an electric charge
as they pass through a high voltage field at the end of the spray
nozzle. This electric charge causes the particles to be attracted to
the parts being painted, which are electrically grounded.
(2) Enclosed spray gun cleaners. Spray guns are typically cleaned
at the end of every job, as well as between color changes. Manual
cleaning of spray guns involves disassembling the gun and placing the
parts in a tray containing an appropriate cleaning solvent. The
residual paint is brushed or wiped off the parts, then the cleaning
solvent is sprayed through the gun after it is reassembled. Enclosed
spray gun cleaners, however, are completely enclosed units that spray
the cleaning solvent through and over the spray gun. The enclosed unit
eliminates most of the exposure of the cleaning solvent to the air,
thereby greatly reducing the organic HAP emissions from evaporation.
(3) Proportional paint mixers. The majority of coatings used in the
aerospace industry are multi-component mixtures, consisting of a base
component and one or more catalyst components. The components must be
thoroughly mixed in the proper ratio immediately before application.
When this mixing is performed manually, a greater volume of coating is
mixed than will actually be used to ensure that there is enough coating
available to complete the job. In contrast, proportional paint mixers
pump each component of the coating directly to the spray gun, where it
is mixed and immediately applied. This results in reduced coating waste
and, consequently, reduced emissions.
c. Work practice standards. Work practice standards are changes in
the method of operation that do not affect the products used in the
process or the process itself, but result in a reduction in emissions.
The aerospace industry has implemented work practice standards programs
for housekeeping measures and managed chemical distribution systems.
Emissions of organic HAP compounds, particularly solvents, can be
reduced by limiting both the amount of the material exposed to the
atmosphere and the length of the exposure. The emission reductions can
be achieved by implementing housekeeping measures whereby solvent-
soaked cloth or paper used for hand-wipe cleaning are placed into bags
or containers that are kept closed. This eliminates the continual
evaporation of the solvent from the cloth or paper when they are not in
use. The bags or containers can then be collected and disposed in such
a manner (e.g., by incineration) to eliminate any further solvent
emissions.
Managed chemical distribution systems centralize the distribution
of solvents and coatings and control the amount of these materials
allowed to be used for a particular task. In this way, waste solvent
and coatings are reduced, and emissions from these waste materials are
reduced.
2. Control Devices
a. Carbon adsorbers. Adsorption systems are used to remove organic
compounds from gas streams when strict limits on the outlet
concentration must be met, or when recovery of the compound is desired.
Adsorption is effective on inlet concentrations ranging from a few
parts per billion to several thousand parts per million, and a flow
rate of several hundred to several hundred thousand cubic feet per
minute. Carbon adsorbers typically have a removal efficiency of 95 to
99 percent.
Once the carbon reaches saturation, it can be removed from the
adsorber vessel and disposed or regenerated. The carbon can also be
regenerated with steam within the adsorber vessel. This option readily
allows for the recovery of the organic compounds for recycling.
b. Incinerators. Two basic types of incinerators, thermal and
catalytic, are used in the aerospace industry to remove organic
contaminants. Each type is discussed below.
(1) Thermal incinerators. Thermal incinerators can be generally
used on air streams with a wide concentration range of organics. These
control devices have minimal dependence on the characteristics of the
organic contaminants, so they can be used to control a wide variety of
emission streams. Thermal incinerators can achieve removal efficiencies
of 98 percent and higher.
The basic operation of thermal incinerators involves raising the
inlet air stream to the incineration temperature of the contaminants
and maintaining the temperature for a specific residence time. The
waste heat content of the incinerator exhaust stream is used to preheat
the inlet air stream. An auxiliary fuel is then typically required to
raise the air stream temperature to the incineration temperature.
(2) Catalytic incinerators. Catalytic incinerators are similar to
thermal incinerators except that they use a catalyst (a substance that
accelerates the rate of oxidation without undergoing a chemical change
itself) to assist in the oxidation of organic compounds to carbon
dioxide and water. These incinerators are typically used for air
streams with a low concentration of organics. The removal efficiency of
catalytic incinerators can be as high as 98 percent.
c. Ultraviolet oxidation. An ultraviolet light oxidation (UVOX)
system has been developed as an abatement device for air streams with
low concentrations of organic compounds. The air stream passes through
particulate filters, then enters a reactor where it is exposed to
ultraviolet light which initiates the oxidation of the organics. Ozone
and other oxygen-based oxidants are injected into the reactor to react
with the organics in the air stream to begin the oxidation of organics
into carbon dioxide and water. A typical removal efficiency for UVOX is
reported to be 95 percent.
d. Activated carbon fiber adsorbent. Another technology has been
developed to control low concentration organic compound emissions
(e.g., paint spray booths). This technology utilizes an activated
carbon fiber adsorbent to initially capture the organic emissions, the
concentration of which is too low to be removed by a control device
such as an incinerator. The adsorbent system consists of a honeycomb
structure element made of activated carbon fiber paper in corrugated
form. This structure adsorbs the organics in the exhaust stream. As the
activated carbon structure becomes saturated, the organics are desorbed
using hot air. This concentrated air stream can then be sent to an
incinerator or other control device. The portion of the activated
carbon structure that was regenerated then begins the adsorption cycle
again.
e. Catalyst-coated filter media. Low concentration organic
emissions (e.g., paint spray booths) can be controlled through the use
of a catalyst-coated filter media. The catalyst material is impregnated
onto the fibers of a dry filter which can then be used wherever
conventional dry filters are used. The catalyst material, unlike
activated carbon, permanently binds the organic material into its
crystalline matrix so that it will not later desorb. In addition to the
coated filters, the catalyst material can be used in a granular form to
control emissions.
f. Filtration systems for inorganic HAP particulate emissions.
Coating operations and blast depainting operations emit inorganic HAP
in the form of particulates. For coating operations, panel-type dry
particulate filters and waterwash spray booths are used to control
these emissions. For blast depainting operations, panel-type dry
particulate filters are also used, as well as baghouses.
The dry filters and baghouses capture particulates by trapping them
as they try to pass through the small passages in the filter media. The
efficiency of the filter media is a function of the particle size, size
of the passages in the filter media, air flow through and pressure drop
across the filter media, and physical characteristics of the particle.
Waterwash spray booths capture particles by forcing the air stream
to pass through a spray or curtain of water. The particles are trapped
by the water and eventually collect as a sludge in the sump of the
spray booth.
V. Rationale for the Proposed Rule
A. Regulatory Development Process for NESHAP
During development of a NESHAP, the EPA collects information about
the industry, including information on emission source characteristics,
control technologies, data from HAP emission tests at well-controlled
facilities, and information on the cost, energy, and other
environmental impacts of emission control techniques. The EPA uses this
information in the development of possible regulatory approaches.
If the source category contains major sources, then a MACT standard
is required. Section 112(d)(3) of the Act defines the minimum
stringency requirements of the MACT standard for new and existing
sources. This level of control is referred to as the MACT ``floor,''
which needs to be determined as a starting point for developing the
regulatory alternatives.
Once the floor has been determined for new and existing sources for
a category or subcategory, the Administrator must set MACT standards
that are no less stringent than the floor level. Such standards must
then be met by all sources within the category or subcategory. However,
in establishing standards, the Administrator may distinguish among
classes, types, and sizes of sources within a category or subcategory
(section 112(d)(1) of the Act). Thus, for example, the Administrator
could establish two classes of sources within a category or subcategory
based on size and establish a different emission standard for each
class as long as each standard is at least as stringent as the floor.
The Act also contains provisions for regulating area sources. However,
except for certain recordkeeping requirements contained in the General
Provisions, these are not relevant to the proposed standards for
aerospace sources, which apply only to major sources.
The next step in establishing a MACT standard is the development
and analysis of regulatory alternatives. First, information about the
industry is analyzed to develop model plant populations for projecting
national impacts, including HAP emission reduction levels, costs, and
energy and secondary environmental impacts. Several regulatory
alternatives (which may be different levels of emission control,
different applicability criteria, or both, and one of which is the MACT
floor) are then evaluated to determine the most appropriate regulatory
alternative to reflect the MACT level.
In addition, although NESHAP are normally structured in terms of
numerical emission limits, alternative approaches are sometimes
necessary. Section 112(h) of the Act provides that if it is not
feasible to prescribe or enforce an emission standard, then a design,
equipment, work practice, or operational standard may be established.
For example, in some cases source testing may be impossible or at least
not practicable due to technological and economic limitations.
In the EPA's decision-making process, the regulatory alternatives
considered for new versus existing sources may be different and each
alternative must be technically achievable. In selecting a regulatory
alternative to represent MACT, the EPA considers the achievable
reduction in HAP emissions (and possibly other pollutants that are co-
controlled), the cost of control, and economic, energy, and other
nonair quality health and environmental impacts. The overall objective
is the achievement of the maximum degree of emission reduction without
unreasonable economic or other impacts.
The selected regulatory alternative is then translated into a
proposed regulation. The regulation implementing the MACT decision
typically includes sections addressing applicability, standards, test
methods and compliance demonstration, monitoring, reporting, and
recordkeeping. The preamble to the proposed regulation, published in
the Federal Register, provides an explanation of the rationale for the
decision. The public is invited to comment on the proposed regulation
during the public comment period. Following an evaluation of these
comments, the EPA reaches a decision and promulgates the final
standards.
B. Determining Maximum Achievable Control Technology (MACT) ``Floors''
Once the EPA has identified the specific major source categories or
subcategories that it intends to regulate under section 112, MACT
standards are set at a level at least as stringent as the ``floor.''
Congress has provided directives to guide the EPA in the process of
determining the regulatory floor.
Congress specified that the EPA must establish standards which
require ``the maximum degree of reduction in emissions of the hazardous
air pollutants * * * that the Administrator * * * determines is
achievable * * *'' (section 112(d)(2) of the Act). In addition,
Congress limited the Agency's discretion by defining the minimum
baseline (floor) at which standards may be set, as follows:
(1) For new sources, the standards for a source category or
subcategory ``shall not be less stringent than the emission control
that is achieved in practice by the best controlled similar source, as
determined by the Administrator,'' and
(2) For existing sources, the standards ``may be less stringent
than standards for new sources * * * but shall not be less stringent,
and may be more stringent than: (A) the average emission limitation
achieved by the best performing 12 percent of the existing sources (for
which the Administrator has emissions information) * * * or (B) the
average emission limitation achieved by the best performing 5 sources *
* * for categories or subcategories * * * with fewer than 30 sources''
(section 112(d)(3)of the Act).
C. Selection of Pollutants and Source Category(ies)
Section 112(b) of the Act lists the HAP to be regulated with
standards established under section 112. Section 112(d), as amended,
requires the EPA to promulgate emission standards for each category or
subcategory of major sources and area sources of the HAP listed in
section 112(b). For the purpose of developing these standards, the EPA
may distinguish among classes, types, and sizes of sources within a
category or subcategory. The NESHAP are to be developed to control HAP
emissions from both new and existing sources pursuant to section 112(c)
of the Act.
The initial source category list (57 FR 31576, July 16, 1992),
required by section 112(c) of the Act, identifies source categories for
which NESHAP are to be established. This list includes all major source
categories of HAP known to the EPA at this time, and all area source
categories for which a finding of adverse effects warranting regulation
has been made.
The source category list identifies ``surface coating processes--
aerospace industries'' as a source category because it contains major
sources emitting at least 10 tons of any one HAP or more than 25 tons
of any combination of HAP annually.
The aerospace industry encompasses original equipment manufacturers
of commercial, civil, and military (including space) aerospace
vehicles. In addition, rework facilities, which repair and repaint
aerospace vehicles, constitute a major portion of the industry. There
are also many subcontractors providing support to the industry,
especially to the OEM's, who subcontract out various portions of the
work. These subcontractors may engage in many of the processes found at
OEM or rework facilities, or in just a few. Further, subcontractors may
conduct operations for non-aerospace industries at facilities at which
they conduct aerospace operations.
For the purposes of this rule, the EPA has defined the source
category as consisting of all facilities engaged in the manufacture or
rework of any aerospace vehicle or component. This includes all OEM's,
rework facilities, and subcontractors. The EPA decided to include
subcontractors in the proposed rule because they perform substantial
amounts of work, much of which could otherwise be carried out at an OEM
or rework facility and which is virtually indistinguishable from
processes at the OEM or rework facility. However, if the
subcontractors' facilities are not major sources, they would not be
subject to the proposed standards.
Early in the development of the proposed standards, the EPA
developed model plants to correspond to the basic structure of the
industry--commercial and military segments, each having OEM and rework
facilities--with the intent of developing subcategories for standards
development, if necessary. On the basis of the information provided,
however, the EPA has found that, with one exception for depainting
operations, there is no need to distinguish among these segments for
the processes for which standards are being proposed under the proposed
rule.
D. Selection of Emission Points Covered by the Proposed Rule
The proposed rule would limit organic HAP emissions from the
following basic aerospace operations: cleaning, primer application,
topcoat application, depainting, chemical milling maskant application,
and the handling and storage of waste. The proposed rule would apply to
all organic HAP emission points within these operations located within
aerospace manufacturing or rework facilities that are major sources. In
addition, the proposed rule would require control of emissions from
these operations if they are performed in any of the operations for
which standards are not being proposed. For example, hand-wipe cleaning
operations are performed at several stages within composite processing
operations. The hand-wipe cleaning operation, a process covered by the
proposed standard, would be subject to the standard, regardless of
where in the facility it occurred.
Standards are being proposed for inorganic HAP emissions from
primer application, topcoat application, and depainting operations.
A discussion of the rationale for including or excluding in this
proposed rule the basic processes listed in Section V.A. is presented
below.
1. Operations for Which Standards Are Being Proposed
a. Organic HAP emissions. As noted above, the EPA is proposing
organic HAP emission standards for cleaning, primer application,
topcoat application, depainting, and chemical milling maskant
application, and the handling and storage of waste. Together, these
operations are estimated to account for approximately 94 percent of the
organic HAP emissions from the industry--cleaning, 87.5 percent;
primers and topcoats, 2.1 percent; depainting, 2.6 percent; and
chemical milling maskants, 1.5 percent.
Based on the information obtained from the section 114
questionnaires and meetings with the industry, there are many readily
available techniques to achieve substantial emission reductions in each
of these operations. For example, many chemical milling maskant
operations were reported as using either solvent-based chemical milling
maskants with control devices or waterborne chemical milling maskants.
With regard to cleaning operations, many product reformulations are
available for hand-wipe cleaning, and there are several equipment and
work practice standards for spray gun cleaning that reduce organic HAP
emissions. While methylene chloride chemical stripping is the prevalent
method for depainting aerospace vehicles, many facilities are using
non-HAP alternatives. These alternatives are being used by both
commercial and military facilities to reduce emissions from depainting
operations. Sufficient data exist for establishing MACT based on non-
HAP alternatives for both commercial and military depainting
operations. Therefore, these processes are included in the proposed
rule. Section 114 questionnaire data and the existence of State and
local regulations identify the use of high transfer efficiency spray
guns in the aerospace industry. Adequate information exists for
establishing MACT for the method of application of primers and topcoats
and for limiting the organic HAP content of the coatings. Based on
section 114 questionnaire data, nearly all facilities employ
housekeeping measures to control emissions from waste storage.
Sufficient data exist, therefore, to establish MACT.
In summary, based upon their relative contribution to overall
organic HAP emissions and the use of demonstrated emission control
technologies and techniques to achieve emission reduction, the EPA
selected these operations for regulation.
b. Inorganic HAP emissions. The EPA is proposing inorganic HAP
emission standards for primer application, topcoat application, and
depainting operations. Based on section 114 questionnaire responses,
there are readily available techniques that are used extensively in the
industry to control these emissions. While the inorganic HAP emissions
do not represent a large percentage of overall emissions from the
industry, the emissions represent potential threats to health because
of the highly toxic nature of the inorganic HAP (e.g., chromium and
cadmium). For these reasons, the EPA selected these operations for
regulation.
2. Excluded Operations
The EPA is not proposing standards for four non-coating related
operations--chemical milling, metal finishing, electrodeposition, and
composite processing--and for four coating-related operations--
adhesives, adhesive bonding primers, sealants, and specialty coatings.
Organic HAP emissions were reported from all four of the non-
coating related processes. Emissions from these four operations account
for less than 1 percent of the total organic HAP emissions from
aerospace facilities. Most of the organic HAP emissions from these
operations are due to emissions from the use of cleaning solvents,
which are being proposed for regulation under the proposed rule. The
EPA has determined that requiring control of the remaining organic HAP
emissions is not feasible because no demonstrated control measures
could be identified. Therefore, the EPA is proposing no further control
for organic HAP emissions from these four operations other than what
would be achieved by the proposed standards for cleaning solvents.
The four coating-related operations--adhesives, adhesive bonding
primers, sealants, and specialty coatings--are similar in many ways to
primers and topcoats, for which organic HAP emission standards are
being proposed. These four coating-related operations account for
relatively small amounts of organic HAP emissions, and the coatings
tend to be very specialized. Subcategorization can be significant,
especially for specialty coatings, resulting in lower potential
emission reductions. Many of the coatings in these four operations
(e.g., sealants and adhesives) are already being applied using high
transfer techniques, including hand application. This results in little
opportunity for emission reduction through improved transfer
efficiency. For spray applied sealants, there is also little
opportunity to use higher transfer efficiency equipment because the
viscosity of these sealants requires the use of high pressure,
conventional spray guns. In terms of potential emission reduction from
lower organic HAP content coatings, virtually no organic HAP content
data were available to categorize these coatings. The time necessary to
gather the data would have significantly delayed this proposed rule.
For all of these reasons, standards are not being proposed for these
operations.
Wastewater and storage tanks emit relatively small amounts of HAP
and, according to the section 114 questionnaire responses, no aerospace
facilities used any means to control these emissions. The EPA then
considered the option of requiring applicable controls used in other
industries on these types of sources. These control measures were
evaluated and found to be too costly when compared to the emission
reductions that would be achieved (approximately $126,000 per ton of
HAP emissions reduction for storage tanks).
Other requirements in the standards may result in a direct
reduction of emissions from wastewater and storage tanks. For example,
the depainting standards may eliminate the majority of the estimated
152 million gallons of HAP-containing chemical stripper usage if the
majority of sources use media blasting methods. This stripper is
typically treated in wastewater treatment systems after use. Also, the
hand-wipe cleaning standards will virtually eliminate the storage tanks
for organic HAP-containing solvents since the use of these solvents
will be significantly reduced. For these reasons, the EPA is not
proposing to regulate HAP emissions from wastewater and storage tanks
in the proposed rule.
E. Selection of the Basis for the Proposed Rule
Section 112 of the Act defines a major source as any stationary
source that emits 9.1 Mg/yr (10 tpy) or more of any one HAP or 22.7 Mg/
yr (25 tpy) or more of total HAP. The Act states that new major sources
must achieve the maximum achievable control technology (MACT), which is
the level of emission control already achieved in practice by the best
controlled similar source. The Act further states that emission
standards promulgated for existing sources may be less stringent than
standards for new sources; however, standards for existing sources must
not be less stringent than the average emission limitation achieved by
the best performing 12 percent of the existing sources.
For all operations being covered by the proposed rule, the EPA has
determined that, taking into account cost, nonair quality health and
environmental impacts, and energy impacts, MACT is equal to the MACT
floors for both existing and new sources. In addition, MACT for new
sources was found to be equal to MACT for existing sources. The EPA has
determined that no further emission reductions can be achieved for new
sources through the use of demonstrated technology than the level of
reduction represented by MACT for existing sources.
To evaluate the regulatory alternatives, model plants were
developed based on market segment (commercial or military), work type
(OEM or rework), and size (small, medium, or large). These
characteristics were examined to determine whether any technological
justification existed to differentiate the proposed standards by market
segment, work type, or size. Based on this examination, the EPA has
determined that, other than one exception under the depainting
standards, there is no justification for differentiating between these
characteristics. For example, rework facilities are required to conform
to OEM specifications, which dictate the processes and coatings that
can be used. Consequently, rework facilities do not typically
incorporate technology that is not used by the OEM's. Also, no
compelling reasons were identified as to why a facility of one size
could not incorporate the technology used by a facility of another
size.
1. Cleaning Operation
According to data obtained from the Bureau of the Census,
approximately 25 percent of facilities with aerospace manufacturing SIC
codes are located in California. Based on information provided by four
California districts--SCAQMD, Imperial County Air Pollution Control
District (APCD), Ventura County APCD, and San Diego APCD--virtually all
of the California facilities are located in these districts, and more
than half are located in the SCAQMD alone. Based on this information,
more than 12 percent of the total number of sources are, then, subject
to the rules in these four districts.
Consequently, the regulations in these four districts (i.e., SCAQMD
Rule 1124, Imperial County APCD Rule 425, Ventura County APCD Rule
74.13, and San Diego APCD Rule 67.9) were examined to determine the
emission limitations in these districts. These regulations specify
vapor pressure limits and housekeeping measures for hand-wipe cleaning
solvents. The EPA then investigated to determine if the regulations
resulted in California facilities emitting less HAP from this process
than facilities outside of California. Based on the section 114
questionnaire responses, California facilities emitted approximately 48
percent less HAP than non-California facilities in ozone nonattainment
areas for hand-wipe cleaning operations. These emissions were
calculated on a pounds of HAP emitted per employee basis, using the
total number of employees at the facilities (the number of employees
for hand-wipe cleaning only was not available). The conclusion made
from these data was that the California regulations are an effective
means of producing permanent and quantifiable emission reductions, and
that the sources subject to these regulations are the best-performing
sources in this source category. Since these sources also comprise more
than 12 percent of the sources in the category, the MACT floor was
based on their control levels.
It was impossible to distinguish the separate effects of
housekeeping and vapor pressure limits on the emission rates from hand-
wipe cleaning operations. Consequently, both were assumed to be
necessary to achieve the calculated emission reductions. While one
cannot ``average'' housekeeping measures, based on common aspects among
the four rules, housekeeping measures of maintaining closed containers
for the storage of fresh solvent, spent solvent, and solvent-soaked
cloth and paper were established as one part of the MACT floor.
The second part of the MACT floor for hand-wipe cleaning is a vapor
pressure limitation on the solvents being used. The SCAQMD, the San
Diego AQMD, and the Imperial County APCD specify a maximum vapor
pressure of 45 mm Hg at 20 deg.C. Ventura County APCD specifies 25 mm
Hg at 20 deg.C. However, the EPA believes that it is inappropriate to
give equal weight to the Ventura rule in determining the MACT floor
because this district contains only three aerospace facilities compared
to the hundreds located in the South Coast and San Diego districts.
Furthermore, industry comments suggested that these three facilities
are not representative of the industry and do not constitute a similar
source as required by the Act. The EPA did, however, consider a
weighted average vapor pressure limitation, but the vapor pressure
value obtained did not correspond to any demonstrated technology. Since
more than half, and possibly as much as 90 percent, of the aerospace
facilities in California are located in the South Coast district, the
EPA has determined that the 45 mm Hg vapor pressure is more
representative of the ``average'' limitation on cleaning solvents among
the best performing facilities and represents the MACT floor for both
new and existing sources. More stringent levels (e.g., a weighted
average vapor pressure value) were not considered to be achievable by
all sources. Therefore, the EPA has selected the 45 mm Hg at 20 deg.C
(24.1 in. H2O at 68 deg.F) as the basis for the standards for
hand-wipe cleaning solvents.
Information collected on cleaning solvents also showed that some
hand-wipe cleaning solvents have both a very low vapor pressure and a
very low evaporation rate. Available data indicate that low evaporation
rates also contribute to minimizing emissions. These cleaning solvents
are demonstrated technology for limited applications and their use
would reduce organic HAP emissions as much as or more than the proposed
vapor pressure limit. Therefore, the EPA is proposing to encourage
their use by including an approved composition list for cleaning
solvents in the proposed rule. The EPA welcomes comments on this list
and proposals for adding to the list before final promulgation of the
rule.
Based on data provided by aerospace facilities in response to the
section 114 questionnaires, spray guns used to apply coatings are
cleaned either manually or in enclosed gun cleaners. Based on
information obtained during plant visits, enclosed gun cleaners are
demonstrated to reduce emissions.
Each of the 61 facilities that reported a spray gun cleaning method
was classified as to whether the spray guns were cleaned manually or
with an enclosed cleaner. Eighteen of the 61 facilities (29 percent)
reported using enclosed gun cleaners; therefore, enclosed gun cleaners
were considered to represent the MACT floor level of control. The EPA
also received information from the industry on the use of cleaning
methods other than enclosed gun cleaners. After review of this
information, the EPA determined that adequate technical justification
was presented to show that the alternate cleaning methods were as
effective as enclosed spray gun cleaners in controlling organic HAP
emissions. Consequently, in addition to enclosed spray gun cleaners,
the EPA is proposing to allow the use of: (1) Unatomized discharge of
solvent into a waste container that is kept closed when not in use, (2)
hand cleaning in a vat that is kept closed when not in use, and (3) the
use of atomized spray into a waste container fitted with a device
designed to capture atomized solvent emissions.
Based on information received from the responses to the section 114
questionnaires, plant visits, and industry meetings, the EPA learned
that there are certain cleaning operations for which low VOC, low HAP,
or low vapor pressure cleaning solvents do not have widespread use that
would constitute a demonstrated technology. The EPA, therefore, is
proposing to exempt these cleaning operations from the requirements to
use cleaning solvents that conform to the approved composition list and
the proposed vapor pressure limit of 45 mm Hg at 20 deg.C (24.1 in.
H2O at 68 deg.F). These operations are listed in Sec. 63.744(e)
of the proposed rule.
The use of cleaning solvents that conform to the approved
composition list is not yet demonstrated for the proposed exempt
cleaning operations. However, there are many new cleaning solvents
being developed, some of which are very close to being used within the
industry for some of these proposed exempt cleaning operations. To
encourage the use of available compliant cleaning solvents and the ones
being developed, the EPA considered imposing a limit on the annual
usage of non-compliant cleaning solvents for exempt operations.
However, no data were available for use in establishing this limit.
2. Primer and Topcoat Application Operations
As noted above, over 12 percent of the aerospace industry is
located in four districts in California. The SCAQMD, Ventura County
APCD, Imperial County APCD, and Sacramento Metropolitan AQMD rules all
require high transfer efficiency coating application methods. The
application methods specified in these rules were adopted as the MACT
floor. The specified methods are electrostatic application, flow coat
application, dip coat application, roll coating, brush coating, and
HVLP spraying.
The EPA recognizes that there may be other application methods that
achieve a level of emissions equivalent to the application methods
allowed in the proposed rule. Therefore, the EPA is requesting comments
identifying these other application methods. These comments should
include test data demonstrating that, in actual production conditions,
the application method achieves a level of emissions at least
equivalent to the level of emissions achieved by HVLP or electrostatic
spray application methods. The EPA will review these comments and,
where adequate technical justification exists, amend the list of
approved application methods.
The EPA also examined whether or not there are demonstrated low
organic HAP content primers or topcoats that could be used in
conjunction with high transfer application methods to establish the
MACT floor to reduce emissions. To this end, the EPA examined State and
local regulations and the data obtained through the section 114
responses.
State and local regulations for aerospace coatings use VOC content
as the means of regulating coating emissions. Consequently, no directed
effort has been made to control the organic HAP content of these
coatings. Data on coating VOC content are readily available from both
the coating manufacturers and the coating users, but no comprehensive
data exist for coating organic HAP content.
The data obtained from the section 114 responses showed that the
organic HAP content varies widely and randomly with the VOC content.
This is not surprising since, as noted above, there have been efforts
to limit only the VOC content in the coatings and not the organic HAP
content. However, the data show that the organic HAP content is
typically 50 percent less than the VOC content. Where the organic HAP
content was higher than the VOC content, the EPA found that this was
the result of the use of exempt solvents (those solvents determined by
the EPA to have negligible photochemical reactivity) that are also
organic HAP.
There are a number of chemicals commonly found in coatings that are
not on the list of 189 HAP (section 112(b) of the Act) including methyl
amylketone (2-heptanone), cyclohexanone, and isopropyl alcohol.
Currently, the EPA does not have adequate health data to determine the
relative toxicity of these organic HAP substitutes and, therefore, does
not want to establish a requirement that would encourage their use as
substitutes in coatings. Since these potential substitutes are also
VOC, the proposed standards would limit both organic HAP and VOC
content, rather than organic HAP only. The effect of this dual limit
will be to reduce the total amount of organic emissions from coating
operations, eliminate the use of the few very high organic HAP content
primers and topcoats, and establish a cap on the organic HAP content of
primers and topcoats that will be developed in the future.
The organic HAP and VOC limits were determined by ranking the
facilities that reported usage of primers or topcoats from the lowest
to the highest weighted average VOC content of all primers or topcoats
used at the facility. The weighted average VOC content that represented
the average of the best 12 percent was selected as the VOC limit. This
value was 350 g/l (2.9 lb/gal) for primers and 420 g/l (3.5 lb/gal) for
topcoats. As discussed earlier, the limited data available to the EPA
indicate that organic HAP content is typically lower than VOC content.
However, no reasonable limit could be identified. Therefore, the EPA is
proposing an organic HAP content limit at the same level as for VOC.
The proposed limits for organic HAP are, therefore, 350 g/l (2.9 lb/
gal) for primers and 420 g/l (3.5 lb/gal) for topcoats.
The section 114 questionnaire responses showed that the inorganic
HAP emissions from nearly all primer and topcoat application operations
were controlled by dry particulate filters or waterwash spray booths.
Since no other technology was identified that can be used to control
inorganic HAP emissions, the use of filters and waterwash was adopted
as the MACT floor.
3. Depainting Operation
The information obtained on depainting operations showed the
pervasive use of organic HAP-containing chemical strippers to remove
paint. However, information was also obtained showing that many
aerospace depainting operations are using alternative methods that do
not utilize organic HAP, including organic HAP-free chemical strippers
and dry media blasting techniques. The information also showed that not
all commercial aerospace vehicles are fully coated. In these instances,
the amount of organic HAP emissions from depainting is less than it
would be if the same vehicle were fully coated.
The quantity of organic HAP emissions from depainting operations at
several commercial rework facilities was readily available. However,
very limited emissions data were obtained through the section 114
questionnaire responses for military aircraft depainting operations.
The EPA considered several parameters to establish which facilities
were the best performing ones. The most simple method would be to
determine the pounds of organic HAP emissions per aircraft. This would
not, however, take into account the difference in outer surface area
from one model of aircraft to another and, hence, the difference in
stripper volume required for each aircraft. Another basis would be to
determine the organic HAP emissions per square foot of outer surface
area actually painted. This method would not distinguish between the
total emissions for stripping an aircraft that has only a portion of
the outer surface area painted, and the total emissions for stripping
the same aircraft with the entire outer surface area painted.
Therefore, both methods were rejected.
Another basis for determining the best performing operations
relates the pounds of organic HAP emissions to the total outer surface
area of the aircraft. This effectively takes into account the
effectiveness of all methods used to depaint aerospace vehicles and
distinguishes the lower emissions achieved when only a portion of the
outer surface area is painted from the emissions when a larger portion
is painted. However, insufficient data were obtained through the
section 114 questionnaire responses to develop an emission rate for
military aircraft depainting operations.
A fourth consideration was to identify the basic techniques being
used and rank them according to their relative effectiveness in
reducing organic HAP emissions. The EPA elected to use this as the
measure for identifying the best performing facilities. The different
depainting techniques were also evaluated as to their applicability
throughout the industry.
Three basic depainting techniques are used by the facilities for
which the EPA has information: Methylene chloride based chemical
strippers, chemical strippers that contain no organic HAP, and blasting
methods. (Although blasting methods are very effective in reducing and
essentially eliminating organic HAP emissions from depainting
operations, they do produce particulate inorganic HAP emissions.
However, these emissions are typically well-controlled with particulate
filters, which are almost always integral to the blasting systems. In
addition, the proposed standards would require such control on
inorganic HAP emissions, as discussed in section II.B. of this
preamble.)
Based on section 114 questionnaires, site visits, and information
provided by the industry, the EPA has information on depainting methods
at 20 facilities. Of these facilities, 14 were identified as using
either a blasting method (i.e., wheat starch or plastic media) or
chemical strippers that contain no organic HAP.
The EPA then determined the aircraft models being stripped at each
of these 14 facilities. This analysis showed that military fighters and
transports, military and commercial helicopters, civil aircraft, and
nearly all models of commercial airliners are currently being stripped
with one or more of these non-HAP methods. Given the wide applicability
of these processes throughout the industry, the EPA determined the MACT
floor to be equivalent to the use of either media blasting or chemical
strippers that do not contain organic HAP.
This analysis also showed, however, that some organic HAP emissions
from depainting still occurred at facilities using blast methods or
chemical strippers that contain no organic HAP. This is due to the fact
that certain parts (e.g., wing flaps, engine nacelles, and radomes) are
removed from the aircraft and depainted separately. This is primarily
due to the fragile nature or specific depainting needs of these parts.
Due to the wide range of parts removed and the inconsistency in the
type of parts removed from one model of aircraft to another, the
applicability of using blast techniques or chemical strippers that
contain no organic HAP on these parts could not be determined.
Consequently, these parts are exempted from the proposed standards.
In addition, the EPA determined that a small portion of the
aircraft cannot be stripped with blasting methods. For example, some
areas of the aircraft are masked to prevent intrusion of the blast
media. The edge of the masking will often cover coated areas and, thus,
prevent the blasting media from removing the coating from these areas.
This coating must then be removed (referred to as spot stripping),
usually with an organic HAP-containing chemical stripper. Another
example of spot stripping is the removal of coatings from a small area
of the outer surface of the aircraft in order to perform testing and
inspection of the bare metal. Also, blasting methods may have
difficulty removing some decals. Consequently, organic HAP solvents may
be used to soften or remove these decals. For these reasons, exemptions
for spot stripping and decal removal are necessary in order to allow
the use of blast depainting methods to meet the proposed standards.
The EPA did, however, seek to limit the amount of organic HAP-
containing chemical strippers used for radome, parts and spot stripping
and decal removal. Data provided in the section 114 questionnaire
responses were used to establish the amount of stripper used for these
operations. Data were not available for radome and parts depainting;
however, usage of chemical strippers for spot stripping and decal
removal was available from commercial airlines for a limited number of
aircraft types. Since information was not available for all aircraft
types, the stripper usage for the largest commercial aircraft was used
as the basis for the usage exemption.
The usage information was, however, limited to commercial aircraft.
Military sources within the aerospace industry provided additional data
to the EPA that established a technical justification for a higher
usage limitation for military aircraft. This information was used as
the basis for the usage limitation for spot stripping and decal removal
for military aircraft.
The section 114 questionnaire responses showed that all facilities
(7 respondents) that use media blasting to depaint use either dry
particulate filters or baghouses to control particulate emissions from
blast depainting methods. While electrostatic precipitators were
identified as a possible control technology, the cost of the
precipitators was believed to be considerably higher than the
filtration methods already in use. Therefore, particulate filters and
baghouses were used as the basis for developing the MACT floor for
operations that use media blasting.
4. Chemical Milling Maskant Application Operation
Not all aerospace facilities perform chemical milling maskant
operations. Of those responding to the section 114 request, twelve
reported chemical milling operations. To identify the best performing
twelve percent of the sources, the emission rate for each source was
calculated by dividing the organic HAP emissions by the total usage of
chemical milling maskants to obtain pounds of organic HAP emitted per
gallon of chemical milling maskant (less water) as applied. The
emissions value took into account control measures such as carbon
adsorbers or waterborne chemical milling maskants. The sources were
then ranked from the lowest emission rate to the highest.
For this operation, the best performing 12 percent of the sources
is represented by the two sources with the lowest emission rates. One
of these sources utilized a carbon adsorber to abate the emissions from
a solvent-based chemical milling maskant. The other source utilized a
waterborne chemical milling maskant with no abatement. Each of these
two facilities had the same organic HAP emission rate of 1.3 lb/gal.
Therefore, this was selected to represent the MACT floor.
5. Handling and Storage of Waste
Based on the section 114 questionnaire responses, 181 non-
wastewater waste streams were reported. Every stream was controlled by
housekeeping measures such as keeping the waste material in closed
drums. Thus, housekeeping measures were established as the MACT floor
for handling and storage of waste.
While no data were available for the effect on emissions from the
housekeeping measures, it is expected that emissions will be reduced
based on the data from California facilities for keeping cleaning
solvents in closed containers. Consequently, housekeeping measures were
used as the basis for the proposed standard.
In addition, existing RCRA regulations govern handling and storage
practices for certain types of wastes. Since the EPA did not want to
create a situation where possible conflicts with the RCRA regulations
could arise, the proposed rule exempts wastes covered under the RCRA
regulations.
F. Selection of the Format of the Proposed Rule
Several formats could be used to implement the control techniques
selected as the basis for the proposed standards. Section 112(d) of the
Act requires that emission standards for control of HAP be prescribed
unless, in the judgment of the Administrator, it is not feasible to
prescribe or enforce emission standards. Section 112(h) of the Act
defines two conditions under which it is not feasible to prescribe or
to enforce emission standards. These conditions are: (1) If the HAP
cannot be emitted through a conveyance device or (2) if the application
of measurement methodology to a particular class of sources is not
practicable due to technological or economic limitations. If emission
standards are not feasible to prescribe or enforce, then the
Administrator may instead promulgate equipment, work practice, design
or operational standards, or a combination thereof.
1. Cleaning Operation
The cleaning operation for which the EPA is proposing standards
emits a variety of organic HAP. For many of these organic HAP, emission
measurement methods either do not exist or would be very expensive to
implement. In addition, the nature of some cleaning operations (e.g.,
hand-wipe cleaning) makes collection through a conveyance device
difficult if not impossible. Therefore, the EPA determined that
emission standards are not feasible for these operations.
The EPA then considered design, equipment, work practice, and
operational standards for these operations. The EPA examined the
California regulations, which had been determined to represent the
floor level of control, to identify the specific types of measures
adopted for hand-wipe cleaning, flush cleaning, and spray gun cleaning.
An analysis by the EPA of the aerospace facilities' data showed that
facilities subject to the California requirements emitted approximately
48 percent less organic HAP from their operations than non-California
operations in ozone nonattainment areas. The EPA concluded that the
formats of the California regulations are effective in providing
quantifiable and achievable emission reductions. Therefore, the same
formats are being proposed for the NESHAP as follows: (1) For hand-wipe
cleaning operations, use of solvents that conform to the approved
composition list or vapor pressure limits, and housekeeping measures,
(2) for spray gun cleaning, an equipment standard and housekeeping
measures, and (3) for flush cleaning, housekeeping measures.
The EPA is also proposing standards to limit the organic HAP
emissions that may occur from leaks from enclosed spray gun cleaners. A
format based on emission limits was not possible, since there were no
data to determine the emissions from leaks. Also, no design, equipment,
or work practice standards were identified that would prevent leaks
from occurring. Consequently, the EPA determined that the only format
that would ensure a minimum of organic HAP emissions from leaks was an
operational standard that required leaks to be repaired within a
certain amount of time.
2. Primer and Topcoat Application Operations
The formats selected by the EPA for the proposed organic HAP
emission limits for primer and topcoat application operations are: (1)
A limitation on both the VOC and organic HAP content, (2) a percent
reduction and performance standard for control devices, and (3) an
equipment standard for the application of primers and topcoats.
The EPA considered a format based on actual emissions from the
primer and topcoat application operations. However, the EPA has
information that many larger facilities have several hundred spray
booths in which primer or topcoat application operations could take
place. Monitoring of that many individual emission sources would not be
feasible for either the facility or for enforcement of the standards by
the EPA or state agencies. In addition, actual emissions would have to
be linked to the production rate and the product produced at the
facility. The EPA does not have adequate data to quantify emissions
based on production or the product produced. Therefore, the EPA
rejected this format.
The EPA then considered a limitation on the organic HAP and VOC
content (mass of organic HAP and VOC per unit volume) of coating as
applied. This format would essentially impose an emission limitation on
each source, but allow flexibility in the manner of compliance. Each
source would have the choice of using compliant coatings and averaging
between compliant and non-compliant coatings. This format will reduce
the amount of total organics, is easily enforced with Method 24 for VOC
content and manufacturer's data for organic HAP content, and will cap
the total amount of organic HAP that a primer or topcoat can contain.
The EPA is also allowing the use of control devices to reduce
organic HAP and VOC emissions from primer and topcoat application
operations. The format of the standards must ensure that as much of the
emissions as practicable are being controlled. The EPA chose a format
that specifies the overall control efficiency (capture efficiency
multiplied by the removal efficiency) because overall control
efficiency is the best representation of the control effectiveness of
control devices. It is also easily enforceable since the EPA has
published test methods for both capture and removal efficiency.
The EPA is proposing to set an equipment standard to reduce HAP
emissions from the application of primers and topcoats. This format
requires the use of certain specified coating application equipment or
coating methods that result in higher transfer efficiencies than
conventional spray equipment, thus reducing emissions. This format
allows facilities the flexibility to choose the method of application
most appropriate to the coating and substrate being coated.
The EPA first considered the data presented in the section 114
questionnaire responses to determine the format of the standards for
inorganic HAP emissions from primers and topcoats. The level of control
(expressed as a percentage) of dry particulate filters and waterwash
spray booths was reported in the section 114 questionnaire responses.
However, the basis for the reported control efficiency was primarily
engineering judgement and manufacturer's data, which could not be
verified through standardized testing. While the Act specifies that
emission standards be developed whenever possible, the EPA determined
that the available data were not of sufficient quality to develop such
a standard.
The EPA then considered an equipment standard that described
physical characteristics of high efficiency particulate filters and
waterwash systems. However, due to the number of different filter and
waterwash systems and variety of designs available, no concise
description could be developed.
The EPA then developed a format that specified that all primer and
topcoat application operations must be conducted in a ventilated booth
or hangar equipped with filters or waterwash systems. The selection of
the actual filters and waterwash systems would be left to the
individual facilities.
3. Depainting Operation
The demonstrated technologies for depainting that represent the
best performing 12 percent of sources are blast methods (e.g., plastic
media and wheat starch blasting) and chemical strippers that contain no
organic HAP. The EPA considered an operational format for the proposed
standards that would require one of these methods to be used. However,
many other alternative depainting methods are under development that
have the potential to reduce organic HAP emissions as effectively as
blasting or chemical strippers that contain no organic HAP. The EPA did
not want to limit the development of these alternative depainting
methods, so the operational format was rejected.
The EPA then considered the level of organic HAP emissions from
blasting, chemical strippers that contain no organic HAP, and other
alternative depainting methods. With the exception of spot, decal,
radome, and parts depainting, all of these methods have the potential
to emit no organic HAP. The EPA, therefore, chose an emission standard
format that specifies no organic HAP emissions from depainting, with
exemptions for spot, decal, radome, and parts depainting. This format
would allow the currently demonstrated depainting methods, as well as
alternative methods that may be developed in the future.
While spot stripping and decal removal have been exempted from the
proposed standards, the EPA, in selecting the format of the exemption,
intends to limit the use of organic HAP-containing stripper to the
lowest amount necessary. The EPA selected a limitation on the annual
average amount (in gallons) of organic HAP-containing stripper used per
aircraft.
The format for the proposed standards for inorganic HAP emissions
from depainting operations was developed from the section 114
questionnaire responses. The seven facilities that reported blast
depainting operations were ranked according to control efficiency of
the filtration methods (particulate filters or baghouses) used to
control particulate emissions. The best performing 12 percent of these
sources are represented by the one facility with the highest control
efficiency. This facility achieved a reported control efficiency of 99
percent and was chosen to represent the MACT floor.
The control efficiency data reported in the section 114
questionnaire responses consisted of engineering judgement estimates
and information obtained from the filter manufacturers. No test data
were reported. Due to this lack of quantifiable test data, the EPA is
requesting comments on whether the 99 percent level of control
represents the demonstrated level of technology for the control of
particulate emissions from blast depainting. These comments should
contain a technical justification, including test data where possible,
for any recommended level of control.
4. Chemical Milling Maskant Application Operation
An emission limitation based on the mass of organic HAP and VOC per
unit volume applied was selected for chemical milling maskants. There
are essentially two means of complying with the proposed standards: (1)
Solvent-based chemical milling maskant with a carbon adsorber to reduce
emissions or (2) a waterborne chemical milling maskant with an organic
HAP content equal to or less than the proposed standard. This format
allows facilities to choose either method (or develop an equivalent
method) without giving preference to either solvent-based or waterborne
chemical milling maskants.
5. Handling and Storage of Waste
The rationale for the format of the proposed standards for handling
and storage of waste is essentially the same as that for housekeeping
measures for cleaning solvents. Since no data were available to
establish an emission limitation and control equipment was not
technically feasible, a work practice format requiring housekeeping
measures was selected as the most appropriate means of reducing
emissions.
G. Selection of Emission Test Methods and Monitoring Requirements
1. Emission Test Methods
In addition to the specific test methods described below for each
affected source, the proposed rule adopts the provisions specified in
Sec. 63.7 of the General Provisions, 40 CFR part 63, subpart A.\9\
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\9\Ibid.
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a. Cleaning operation. For hand-wipe cleaning, the proposed
standards would allow owners or operators to use either a cleaning
solvent that conforms to an approved composition list or a cleaning
solvent with a vapor pressure less than or equal to 45 mm Hg.
Procedures are, therefore, necessary for determining whether a cleaning
solvent conforms to the approved composition list or meets the vapor
pressure limitation.
The other portion of the proposed standards for cleaning operations
(including spray gun cleaning) includes housekeeping measures,
equipment standards, or work practice standards, for which no test
methods or procedures are required to demonstrate compliance.
Those facilities that use cleaning solvents that conform to the
approved composition list would have to demonstrate how the solvents
comply. The EPA is proposing that data supplied by the manufacturer of
the cleaning solvent be used to show compliance. The data must show all
components of the cleaning solvent and demonstrate that one of the
approved composition definitions is met.
To determine the composite vapor pressure of a cleaning solvent,
the EPA is proposing that for single-component cleaning solvents data
supplied by the manufacturer or from standard engineering reference
texts be used. This information is readily available and, for single
component cleaning solvents, should be readily acceptable.
For multi-component cleaning solvents, it is necessary to determine
the composite vapor pressure of the cleaning solvent. This requires
determining the amount of each organic compound in the cleaning solvent
and each one's vapor pressure. Once these are known, then a procedure
to combine the information must be followed to calculate the composite
vapor pressure.
The EPA is proposing that gas chromatographic analysis, following
the procedures outlined in E 260-85, be used to quantify the amount of
each organic compound. The vapor pressure of each organic compound
would then be determined, again, either by the manufacturer's data or
from standard engineering reference texts, as discussed above. For
combining these data to calculate the composite vapor pressure, the EPA
is proposing that the blend be assumed to be an ideal solution where
Raoult's law applies. While more accurate methods are available, the
cost and time to conduct those methods and the small gain in accuracy
are not justifiable when compared to the ease of calculating composite
vapor pressure assuming an ideal solution where Raoult's law applies.
Further, the composite vapor pressure of any blend changes with the
conditions under which it is applied. This normal variability would
cause some cleaning solvents to meet the composite vapor limit under
certain conditions, but not others, if the vapor pressure test methods
were used instead of the calculation.
b. Primer and topcoat application operations. One part of the
proposed standards for primer and topcoat application operations
requires the use of specified high transfer efficiency application
equipment, or equivalent.
As long as this equipment is installed, operated, and maintained
according to manufacturer's specifications, it should perform with high
transfer efficiency. Therefore, the EPA is not proposing any test
methods or procedures for this part of the primer and topcoat
standards.
Owners or operators who want to use application equipment other
than that specified in the proposed rule must demonstrate that it is
equivalent in reducing organic HAP and VOC emissions. To make an
equivalency determination, the owner or operator must demonstrate that
the organic HAP and VOC emissions generated by the alternative method
are equal to or less than the emissions generated by HVLP or
electrostatic spray guns under the actual production conditions in
which the alternative method is intended to be used. This level of
emissions is equivalent to the emissions demonstrated by California
facilities that are subject to similar rules.
Before implementing the alternative application method, the
facility must determine the organic HAP and VOC emissions that were
generated by the process over the 90-day period immediately preceding
the implementation of the alternative application method. During this
initial 90-day period, only HVLP or electrostatic spray guns could be
used. These emissions would be compared to the organic HAP and VOC
emissions generated by the same process using the alternative
application method to coat an equivalent amount of parts and assemblies
as coated during the initial 90-day period using identical coatings.
The organic HAP and VOC emissions generated during the use of the
alternative application method must be equal to or less than the
emissions generated during the initial 90-day period.
In determining compliance with the organic HAP and VOC content
levels, an owner or operator would have the flexibility to use
compliant coatings or to average uncontrolled compliant and non-
compliant coatings. (Averaging between primers and topcoats would not
be allowed, nor would averaging between controlled and uncontrolled
coatings.) Test methods and procedures are, therefore, necessary to
determine the organic HAP and VOC content of each primer and topcoat as
applied.
The EPA is proposing that Method 24 be used for determining the VOC
content. This is a long-standing method for such determinations.
Sources may, at their discretion, use manufacturer's data for
determining the VOC content rather than Method 24. However, if there is
found to be a difference in the VOC content as determined from the
manufacturer's data and that determined using Method 24, then the value
obtained using Method 24 will always take precedence in compliance
determinations. Since there are no generally available methods for
testing organic HAP content, the EPA is proposing that the organic HAP
content level be determined by each facility based on the formulation
of each coating. The formulation data would be supplied to the facility
by the coating manufacturer. This would reduce the burden to the
industry and promote consistent identification of the total organic HAP
content among all users. Several coating manufacturers have indicated
to the EPA that they are willing to supply such information.
As noted above, the proposed standards would require the organic
HAP contents to be determined on a ``less water as applied'' basis and
VOC contents on a ``less water and exempt solvents as applied'' basis.
Thus, unless the coating is applied as received, procedures must be
adopted to change ``as received'' organic HAP and VOC content levels to
``as applied'' levels. This could be accomplished by analyzing a sample
of the coating as applied using Method 24 or through a calculation. The
calculations to do this are well known and established (see A Guideline
for Surface Coating Calculations, EPA-340/1-86-016, July 1986) and,
thus, the EPA did not consider it necessary to include the basic
calculation formulas in the proposed rule. A determination of what is
added to the coating before it is applied must be made so that the ``as
applied'' levels can be calculated. The EPA is proposing that each
owner or operator make such determinations on the basis of records kept
at the facility. These are records that will be required by the
proposed rule and will be readily available to the owner or operator
for making the necessary calculations. The pertinent information (i.e.,
density, organic HAP content, and VOC content) of the additives would
be based on manufacturer supplied information. If that information is
not available, then the owner or operator would be required to develop
a procedure for determining the missing information for approval by the
Administrator.
Since the proposed standards for organic HAP and VOC content levels
would allow each owner or operator to average organic HAP or VOC
content levels across uncontrolled primers and across uncontrolled
topcoats, the procedures provide the necessary formulas to calculate
the volume-weighted average organic HAP or VOC across all primers or
topcoats. For compliant coatings, the EPA is proposing less complicated
procedures for demonstrating compliance. This is appropriate because
each coating by itself as applied meets the organic HAP (or VOC)
content level, and daily calculations of the volume-weighted average
HAP and VOC content as applied are not necessary. The proposed rule
does, however, require monthly determination of usage and HAP and VOC
content as applied.
If control devices (e.g., incinerators, carbon adsorbers) are used,
the proposed standards require them to achieve an overall control
efficiency of at least 81 percent. For control devices other than
carbon adsorbers, it is necessary, therefore, to identify the capture
efficiency of the capture system, the destruction efficiency of the
control device, and, where feasible, operational parameters that would
be monitored to ensure continuous compliance. The proposed standards
also include provisions for determining the capture and removal
efficiencies. The test methods and procedures being proposed for
determining the capture and removal efficiencies are those that are
typical for control devices.
The EPA is proposing that capture efficiency be determined by one
of two methods depending on whether the capture system is totally
enclosed or not. A total enclosure would be verified according to the
provisions specified in Sec. 52.741, appendix B, Procedure T of 40 CFR
part 52 (and, thus would have a capture efficiency of 100 percent). The
capture efficiency of all other systems would be determined according
to the procedures specified in Sec. 52.741(a)(4)(iii) of 40 CFR part
52.
The EPA is proposing that the removal efficiency of a control
device be determined based on three runs, each run lasting one hour.
For control of organic compounds, Method 1 or 1A of 40 CFR part 60,
appendix A, as appropriate, would be used for selection of the sampling
sites, and the gas volumetric flow rate would be determined using
Methods 2, 2A, 2C, or 2D of 40 CFR part 60, appendix A, as appropriate.
Method 18 of 40 CFR part 60, appendix A, would then be used to measure
either TOC minus methane and ethane or total organic HAP.
Alternatively, any other test method or data that has been validated
according to the applicable procedures in Method 301 of 40 CFR part 63,
appendix A, may be used.
Where a carbon adsorber is used, the EPA is proposing to use a mass
balance procedure for determining the overall control efficiency. The
proposed rule contains procedures as specified in 40 CFR 60.433 for
using a mass balance approach that would calculate the amount of
organic HAP and VOC applied and the amount recovered. This information
would then be used to calculate the overall control efficiency of the
carbon adsorber.
In addition, Method 309 is being proposed for determining the
number of consecutive 24-hour periods in the rolling material balance
period for carbon adsorbers.
Each owner or operator using a control device would be required to
conduct an initial performance test. For control devices other than
carbon adsorbers, this test would consist of 3 one-hour runs. For
carbon adsorbers, the test would span the number of days specified for
the rolling material balance period as calculated by proposed Method
309. In addition, it is necessary to establish, during the initial
performance test, operating parameters that would be continuously
monitored in order to show continuous compliance. For incinerators
other than catalytic incinerators, the operating parameter would be the
firebox temperature. For catalytic incinerators, the operating
parameters would be the temperature of the gas stream immediately
before and after the catalyst bed. No operating parameters are required
to be monitored on carbon adsorbers since the material balance
calculations provide a continuous check of proper operation.
c. Depainting operation. The proposed standards for the depainting
of aerospace vehicles requires, in part, no organic HAP emissions,
which will be achieved through the use of chemical strippers that do
not contain any organic HAP or the use of non-chemical depainting
methods or techniques. Since all of the known non-chemical depainting
methods/techniques do not contain any organic HAP, the only test method
or procedures needed are those associated with determining whether a
chemical stripper contains any organic HAP. For the reasons noted
earlier under the discussion on test methods for primers and topcoats,
the EPA is proposing that the organic HAP content be determined based
on information supplied by the manufacturer of the chemical stripper.
In order to demonstrate compliance with the organic HAP-containing
chemical stripper usage limitation for spot stripping and decal
removal, the source must calculate an average annual usage per
aircraft. Since there is only one method to calculate this average
(i.e., dividing the total gallons of organic HAP-containing chemical
stripper used for spot stripping and decal removal by the number of
aircraft stripped), the EPA is proposing to use this method to
determine compliance. The information needed for this calculation would
be obtained from company records.
Particulate inorganic HAP emissions are generated by blast
depainting methods. Therefore, the EPA is proposing that Method 5 of 40
CFR part 60, appendix A, be used to determine the control efficiency of
particulate filtration systems used on this process.
d. Chemical milling maskant application operation. The proposed
standards for chemical milling maskants limits the organic HAP content
to the equivalent of 160 grams per liter (1.3 pounds/gallon) less water
as applied and limits the VOC content to the equivalent of 160 grams
per liter (1.3 pounds per gallon) less water and exempt solvents as
applied. In determining compliance with the organic HAP and VOC content
levels, an owner or operator would have the flexibility to use
compliant chemical milling maskants or averaging uncontrolled compliant
and non-compliant maskants. As for primers and topcoats, averaging
uncontrolled and controlled chemical milling maskants together would be
prohibited. Test methods and procedures are, therefore, necessary to
determine the organic HAP and VOC content of each chemical milling
maskant as applied. If control devices are used, it is also necessary
to determine the overall control efficiency of the control device. The
test methods selected and the rationale for the selection are identical
to those presented above for primers and topcoats.
e. Handling and Storage of Waste. For those wastes subject to the
proposed rule, no test methods or procedures are required to
demonstrate compliance with the proposed housekeeping measures.
2. Monitoring Requirements
In accordance with paragraph (a)(3) to section 114 of the Act,
enhanced monitoring of stationary sources is required to determine the
compliance status of the sources, and whether compliance is continuous
or intermittent. For affected sources complying with the proposed
standards through the use of control devices, initial compliance is
determined through the initial compliance test, and ongoing compliance
through continuous monitoring. The EPA has proposed the parameters to
be monitored for certain types of control devices now used in the
industry. The values of these parameters that correspond to compliance
with the proposed standards are set by the owner or operator during the
initial compliance test. If future monitoring indicates that control
equipment is operating outside of the range of values established
during the initial performance test, then the owner or operator is out
of compliance with the proposed standards, except as specified for
malfunctions in Sec. 63.6(e)(3) of 40 CFR part 63, subpart A.10
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\1\0Ibid.
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a. Cleaning operation. For cleaning operations, the only portion of
the standards for which monitoring requirements are being proposed is
for enclosed spray gun cleaner systems. These systems are stationary
sources that have the potential to emit organic HAP from around ill-
fitting or worn seals or from leaking pumps or piping connections. The
effectiveness of these systems thus depends on their being ``vapor-
tight'' and that there are no leaks from the pumps or piping of these
systems. Therefore, the EPA is proposing that such systems be visually
inspected for leaks. Since most of the systems are used to clean paint
spray guns, leaks would be easily spotted by visual inspection as the
result of solvent or paint residue escaping around the source of the
leak. The EPA does not believe that monitoring with leak detection
equipment would provide a significant increase, if any, in the
detection of leaks from these systems. Therefore, the EPA is proposing
to require visual inspection only.
The EPA then considered how frequently the enclosed cleaners should
be inspected. The EPA considered daily, weekly, monthly, and yearly
frequencies. The nature of the systems being inspected is not expected
to result in sudden failure, but rather failure due to wear and tear.
Thus, the EPA considered it unnecessary to require daily or even weekly
inspection. On the other hand, one year was considered too long for a
leak to go unrepaired. Therefore, the proposed standards would require
a monthly inspection of the systems. The EPA believes that this is a
reasonable period between inspections, without overburdening the
industry and not allowing leaks to go unrepaired for an extended period
of time.
Similarly, the proposed work practice and equipment standards
require that containers used to store solvents and solvent laden cloth
and paper be closed when not in operation. The EPA could not identify
any operating parameter that would monitor whether this was being done.
Nor could the EPA identify a parameter to monitor when atomized
cleaning is used. The proposed standards require the use of a device
designed to capture the atomized solvent emissions. No monitoring
parameters were identified to indicate periods when the device may not
be functioning or when it may have been removed. Rather, the
determination would be made during enforcement inspections as to
whether the proper procedures were being followed.
b. Primer, topcoat, and chemical milling maskant application
operations. The proposed monitoring requirements for primer, topcoat,
and chemical milling maskant application operations concern the
operation of control devices that may be used in demonstrating
compliance with the organic HAP content levels. For control devices,
the parameters to be monitored are those that have been typically used
in other standards. For example, where catalytic incinerators are used
to control organic HAP and VOC emissions, the proposed standards
require that the temperature of the air stream be monitored immediately
before and after the catalyst bed. The rationale for selecting the
various control device parameters in this proposed rule is long
standing, and for more information see the proposal notice for the
SOCMI reactor processes NSPS (55 FR 26966 through 26969, June 29,
1990). The EPA is, therefore, simply proposing to adopt the same
monitoring parameters as have been required for previous standards.
For inorganic HAP emissions from primers and topcoats, the proposed
standards would require the use of particulate filters or waterwash
systems. Two parameters were identified that could be monitored that
directly relate to the performance of the system--air flow and pressure
drop. The proposed rule, however, would require monitoring of only the
pressure drop across the filter or waterwash since the air flow is
directly related to the pressure drop. Monitoring of both parameters
was considered to be redundant.
c. Depainting operation. The nature of the proposed standards for
depainting operations is such that no meaningful monitoring requirement
was identified for the proposed organic HAP emission standards. The
organic HAP content (less water as applied) of the chemical strippers
used must be calculated or determined. But once identified, there are
no requirements concerning their application.
The rationale for the pressure drop monitoring requirements
proposed for inorganic HAP emissions from depainting operations is
identical to that for primers and topcoats.
d. Handling and storage of waste. For those wastes subject to the
proposed rule, the EPA could not identify any operating parameters that
would monitor whether housekeeping measures were being performed.
Therefore, no monitoring requirements are being proposed.
H. Selection of Recordkeeping and Reporting Requirements
1. Recordkeeping
In addition to the specific recordkeeping requirements described
below for each affected source, the proposed rule adopts the provisions
specified in Sec. 63.10 (a), (b), (d), and (f) of the General
Provisions, 40 CFR part 63, subpart A.11 These were the only
paragraphs from Sec. 63.10 that were considered to be applicable to the
proposed rule.
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\1\1Ibid.
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a. Cleaning operation. The proposed standards for hand-wipe
cleaning operations require cleaning solvents to be used that either
comply with the approved composition list or have a composite vapor
pressure less than or equal to 45 mm Hg at 20 deg.C (24.1 in. H2O
at 68 deg.F). In order to determine whether these requirements are
being complied with, it is necessary to keep data on the cleaning
solvents being used in these operations. Therefore, the EPA is
proposing that each owner or operator keep for each cleaning solvent
used at the facility, a record of the name of the cleaning solvent and
documentation that shows the organic HAP content and organic HAP
constituents. In addition, the EPA is proposing the following records
for specific cleaning operations be kept.
For each cleaning solvent used in hand-wipe cleaning operations
that conforms to the approved composition list, the records that would
be maintained are the name of each cleaning solvent, documentation
demonstrating compliance to the approved composition list, and annual
purchasing records showing the annual volume purchased of each. For
each cleaning solvent used in hand-wipe cleaning operations that does
not conform to the approved composition list, but does conform to the
vapor pressure requirement, the information required to be recorded
would be the name of each cleaning solvent, the monthly usage of the
cleaning solvent at each operation, the composite vapor pressure, the
manufacturer's data sheets or other documentation of the vapor
pressure, and any test reports and calculations performed to determine
the composite vapor pressure (in order to assess compliance with the
vapor pressure limit).
The proposed standards would allow certain hand-wipe cleaning
operations to be exempt; that is, cleaning solvents that do not comply
with the approved composition requirements or with vapor pressure
greater than 45 mm Hg at 20 deg.C (24.1 in. H2O at 68 deg.F) can
be used for these exempt cleaning operations. Therefore, affected
facilities will have both compliant and non-compliant cleaning solvents
in use. The EPA, therefore, believes it is necessary to ensure that
cleaning solvents with vapor pressures greater than 45 mm Hg at 20
deg.C (24.1 in. H2O at 68 deg.F) are only used for the exempted
cleaning operations. To this end, the EPA is proposing that each owner
or operator keep daily records of the name and volume of each cleaning
solvent used in each exempt hand-wipe cleaning operation, as well as
the parts, assemblies, or subassemblies on which it is used. The EPA is
requiring daily recordkeeping for these non-compliant solvents so that
adequate records exist to determine that the solvents are used only in
the exempt operations.
The EPA is also proposing that records be kept of each leak found
when visually inspecting enclosed spray gun systems. These records
would consist of source identification, the date of discovery of the
leak, and the date of repair in order to ensure that repairs are
completed within 15 days as required by the proposed standard.
For those portions of the cleaning operation standards that require
containers to be closed when not in use, the EPA is not proposing any
recordkeeping requirements. Nor is the EPA proposing any recordkeeping
requirements for the cleaning of spray guns (other than for enclosed
spray gun cleaners) or flush cleaning.
b. Primer and topcoat application operations. For all primer and
topcoat application operations, regardless of which methods are used to
comply with the proposed standards, the EPA is proposing that each
owner or operator keep records of the name of each coating and its
organic HAP and VOC content as received. In addition, the EPA is
proposing different levels of recordkeeping requirements depending on
how the organic HAP and VOC content levels are being met. If an owner
or operator is using compliant coatings to meet the organic HAP or VOC
content levels, the EPA is proposing that the owner or operator keep
records that identify for each coating (primer, topcoat) used each
calendar month, the volume of each coating formulation used each month,
the masses of organic HAP and VOC emitted per unit volume as applied,
and the manufacturer's data, calculations, and test results (including
Method 24 results taken during an enforcement inspection) used to
determine organic HAP and VOC content of each as applied. Daily records
are not necessary since, if the coatings are compliant, the emissions
from the coatings will not exceed the emission limitation in the
proposed standards on a daily basis. Monthly records, however, are
necessary to maintain a check that compliance is being maintained.
If an owner or operator elects to meet the organic HAP or VOC
content level by averaging, the EPA is proposing that records of the
daily volume-weighted average organic HAP and VOC contents for primers
and topcoats be kept as well as all of the data and calculations used
to calculate these values. This would include the volume, organic HAP
content as applied, and VOC content as applied of each coating. This
level of information is required for an inspector to determine whether
the facility was in compliance and whether the proper data and
calculations were being used.
If a control device is used, each owner or operator would be
required to keep a record (or, where allowed in the proposed standards,
daily averages) of the various control device operating parameters
being monitored. Since for some control devices compliance with the
proposed standards is dependent on the control device being operated
properly, these records are necessary to determine compliance.
Specifically, a source would be out of compliance if the recorded
parameters were out of range. As noted earlier, for incinerators, this
would be continuous records of the operating temperature(s), while no
operating parameters are required for carbon adsorbers. Thus, the EPA
is requiring these records for compliance determinations.
The recordkeeping requirements for inorganic HAP emissions from
primers and topcoats, which require recording of the pressure drop
across the filters or waterwash once per shift during which coating
operations occur, were included to provide a means of obtaining data
that can be used to verify that the pressure drop limits are not being
exceeded. The records can also be used by the facility to determine
when preventative maintenance should be performed on the filter or
waterwash system. The proposed rule would also require that the log
include the pressure drop operating range as specified by the
manufacturer so that the compliance information is readily available at
all times.
c. Depainting operation. For compliance with the standard of no
organic HAP emissions through the use of chemical strippers that
contain no organic HAP, the minimum records identified were the name of
each chemical stripper used in depainting operations, the organic HAP
content of each stripper, and its supporting documentation.
The proposed standards contain an exemption for spot stripping and
decal removal that is based on an annual average volume of organic HAP-
containing stripper per aircraft. To ensure that this exemption is
being complied with, the EPA is proposing that the owner or operator of
an affected source record these annual averages. Consequently, records
must be maintained of the number of aircraft depainted, the volume of
organic HAP-containing stripper used for spot stripping and decal
removal, the average number of gallons of organic HAP-containing
chemical stripper used per aircraft, and all supporting data and
calculations.
Similarly, the proposed standards have an exemption for radomes and
parts depainting. While radomes are self-evident, the parts normally
removed are not. Therefore, the EPA is proposing that each owner or
operator keep an up-to-date list of all aircraft depainted at the
facility and a list of all parts normally removed prior to depainting
from each aircraft model.
The EPA believes that it is necessary to ensure that, if a
depainting facility uses organic HAP-containing chemical strippers,
they only be used on spot stripping, decal removal, radomes and parts.
Tracking the daily use of the organic HAP-containing chemical strippers
by volume would indicate whether or not these strippers are being used
on the aircraft body. The amount of stripper required to depaint an
aircraft body is substantially higher than for the exempted operations.
Therefore, an accounting of stripper usage is necessary to ensure
organic HAP-containing stripper is not being used on the aircraft body.
The EPA considered requiring records of the usage of both strippers
that contain organic HAP and those that do not contain organic HAP be
maintained. However, the EPA believes that requiring records of both
types of stripper usage would be overly burdensome to the industry and
that adequate accounting would be obtained from the usage of organic
HAP-containing chemical stripper. In addition, records of the usage of
organic HAP-containing strippers are already being required for spot
stripping and decal removal. Consequently, the EPA is proposing that
records be kept only of the organic HAP-containing chemical stripper
usage.
Daily recordkeeping of the usage of these strippers was considered
to be unnecessary since the intent of the records is to show long-term
trends. Annual records, on the other hand, would require too long of a
period to establish these trends. Consequently, the EPA is requiring
monthly records of the organic HAP-containing stripper usage.
Whenever non-chemical depainting techniques are being used, the
proposed standards would require that during periods of malfunction,
alternate depainting methods be used for no more than 14 consecutive
days unless the alternative method contains no organic HAP. In order to
determine compliance with these requirements, records must be kept on
the dates the malfunction occurred and was corrected, the methods used
to depaint the aerospace vehicles during the malfunction, and the dates
that these methods were begun and discontinued.
For inorganic HAP emissions, records of the daily pressure drop
readings are necessary to ensure that the requirements of the proposed
standards are being met. The rationale for this requirement is
identical to that presented for primers and topcoats. In addition,
records must be maintained of the manufacturer's recommended pressure
drop limits, the particulate filter control efficiency, and all test
results, data, and calculations used in determining the control
efficiency so that compliance determinations can be made.
d. Chemical milling maskant operation. For the organic HAP and VOC
content levels, the EPA is proposing different levels of recordkeeping
requirements depending on how the organic HAP and VOC content levels
are being met. The selection of and rationale for these recordkeeping
requirements are identical to those presented above for primers and
topcoats. In addition, where carbon adsorbers are used to control
organic HAP and VOC emissions from chemical milling maskants, the same
recordkeeping requirements as discussed for primer and topcoat
application operations are being proposed, and the rationale is the
same.
e. Handling and storage of waste. Since the proposed standards
would exempt RCRA wastes, it is necessary to identify which wastes are
subject to RCRA and which are subject to the proposed rule. Therefore,
the EPA is proposing that each owner or operator keep an up-to-date
list of which wastes are subject to RCRA requirements and which are
subject to the proposed rule, and to keep on file the documentation
supporting these determinations.
The EPA received a comment requesting that records be maintained of
the quantity and type of solvents stored and disposed, as well as the
disposal facility (if applicable). The purpose of these records would
be to ensure that the wastes are not improperly disposed since the
wastes may not be RCRA listed wastes (and, thus, not subject to
applicable RCRA recordkeeping requirements). The EPA is requesting
additional comments concerning the addition of these recordkeeping
requirements. The comments should address whether there are any wastes
that contain HAP that are not subject to RCRA and, if so, whether the
recordkeeping requirements under these standards should apply to all
affected waste streams or only non-RCRA listed waste streams. In
addition, the comments should address what burden these requirements
would impose.
2. Reporting Requirements
In addition to the specific reporting requirements described below
for each affected source, the proposed rule adopts the provisions
specified in Sec. 63.9(a) through Sec. 63.9(e) and Sec. 63.9(h) through
Sec. 63.9(j) and Sec. 63.10 (a), (b), (d), and (f) of the General
Provisions, 40 CFR part 63, subpart A.12 However, certain time
periods specified in these sections were changed as detailed in Section
II.F of this preamble. These time periods were changed in order to
provide additional time for the EPA to review requests for changes to
time periods for submittal of reports and for owners or operators to
respond to EPA requests. These were the only paragraphs from these
sections (i.e., Sec. 63.9 and Sec. 63.10) that were considered to be
applicable to the proposed rule.
---------------------------------------------------------------------------
\1\2Ibid.
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The proposed rule would require an owner or operator to submit the
following four types of reports:
(1) Initial notification,
(2) Notification of compliance status,
(3) Periodic reports, and
(4) Other reports.
The purpose and contents of each of these reports are described in
this section. The wording of the proposed rule requires all reports to
be submitted to the ``Administrator.'' The term Administrator refers
either to the Administrator of the EPA, an EPA regional office, a state
agency, or another authority that has been delegated the authority to
implement this rule. In most cases, reports will be sent to state
agencies. Addresses are provided in the General Provisions of 40 CFR
part 63, subpart A.13
---------------------------------------------------------------------------
\1\3Ibid.
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Records of reported information and other information necessary to
document compliance with the regulation are required to be kept for 5
years. Per the General Provisions, the 2 most recent years must be kept
on-site; the other 3 years may be kept off-site. Records pertaining to
the design and operation of the control and monitoring equipment must
be kept for the life of the equipment.
a. Initial Notification. The proposed standards would require
owners or operators who are subject to this subpart to submit an
initial notification. As outlined in the General Provisions, 40 CFR
63.9, this report serves two basic purposes: (1) Notifies the EPA that
an existing facility is subject to the proposed standards and (2)
notifies the EPA of the construction of a new facility.14 A
respondent must also report any facility modifications as defined in
Sec. 63.5. This report will establish an early dialogue between the
source and the regulatory agency, allowing both to plan for compliance
activities. The notice is due no later than 12 months before the final
compliance date as specified in the proposed standards. Under the
proposed rule, the initial notification is not required from any source
that has submitted a permit application under title V of the Act,
provided that the permit application has been submitted by the same due
dates as for the initial notification and that the state to which the
permit application has been submitted has a permit program in place and
has received delegation of authority from the EPA.
---------------------------------------------------------------------------
\1\4Ibid.
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As called for by the General Provisions, each owner or operator of
an affected source would be required to submit a start-up, shut-down,
and malfunction plan. This plan would be submitted with the initial
notification.
b. Notification of Compliance Status. As adopted through the
General Provisions, owners or operators who are subject to this subpart
would be required to submit a notification of compliance status. This
report contains the information necessary to demonstrate that
compliance has been achieved, such as the results of performance tests,
Method 24 tests, and design analyses, as well as the methods that will
be used for determining continuing compliance as outlined in the
General Provisions, 40 CFR 63.9.15 Another type of information to
be included in the notification of compliance status is the specific
range of each monitored parameter for each affected source, the
rationale for why this range indicates compliance with the emission
standard, and whether each source has operated within its designated
operating parameters. The report would be due within 150 days after the
final compliance date as specified in the General Provisions.
---------------------------------------------------------------------------
\1\5Ibid.
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Although not specified in the proposed rule, a description of
information specific to the aerospace industry that should be contained
in the initial compliance notification for each of the affected sources
was presented earlier in this preamble (see Section II.B.2, Reporting
Requirements). The information presented in that section is not
necessarily exhaustive.
c. Periodic Reports. The EPA is proposing to adopt a standard basis
for submitting periodic reports for each of the operations for which
standards are being proposed. Semiannual reports would be required
whenever an operation was found to be in non-compliance or whenever a
monitored parameter exceeded its value. For example, for a primer
application operation where averaging is used, a semiannual report
would be triggered for any daily period covered by the semiannual
report in which the daily primer volume-weighted average organic HAP
content limit was exceeded.
Semiannual reports would also be required whenever a change
occurred at a facility that might affect a source's compliance status
or that introduces a new element to the operation that was required to
be reported in the notification of compliance status. For example,
reformulation of a chemical milling maskant may change the organic HAP
content of the maskant. If the HAP content increases, then the owner or
operator may have to average different or additional chemical milling
maskants together, or add a control device in order to maintain
compliance. This change in compliance status would trigger a semiannual
report.
For operations that did not experience any exceedances or changes,
the EPA is proposing that annual reports be submitted to this effect.
In addition, annual reports are required where compliance is determined
on an annual basis and exceedances of these annual limits occur.
The EPA is proposing to adopt the above schedule of reporting
because it provides a fair balance between the need to know certain
information in a timely fashion and reduces the burden to industry and
provides consistency within this regulation. The following paragraphs
discuss in more detail the specific types of information to be included
in these various periodic reports. The information being requested is
that which the EPA believes is necessary in the enforcement of the
proposed rule.
(1) Cleaning operation. Periods of non-compliance would be
transmitted to the EPA in a semiannual report. An example of non-
compliance for hand-wipe cleaning is the use of a cleaning solvent with
a vapor pressure greater than 45 mm Hg (24.1 in. H2O at 68 deg.F)
and does not conform to the approved composition list in a nonexempt
cleaning operation. In addition, any instance where a leaking enclosed
spray gun cleaner is not repaired within 15 days would be considered an
instance of non-compliance that would trigger a semiannual report.
The EPA is also proposing a semiannual reporting requirement if
changes, such as the use of new cleaning solvents, previously reported
cleaning solvents no longer in use, or new cleaning techniques for
spray guns, are made to the cleaning operations at the facility. Where
a new or reformulated cleaning solvent is used, the semiannual report
would include documentation of its vapor pressure or documentation that
it conforms to the approved composition list.
If the cleaning operation has been in compliance for the annual
period, then an annual report would be required occurring every 12
months from the date of the initial report stating that the cleaning
operation has been in compliance with the applicable standards.
(2) Primer, topcoat, and chemical milling maskant application
operations. A semiannual report would be required whenever an
exceedance of organic HAP or VOC content levels occurred, as well as
any time a primer or topcoat application operation was not immediately
shut down when the pressure drop across the filters or waterwash was
out of range. Where control devices are used to comply with the organic
HAP or VOC content levels, the EPA is also proposing to require
semiannual reporting whenever a monitored parameter falls outside its
appropriate range. Such situations indicate noncompliance with the
proposed standards.
If no exceedances occur, each owner and operator would submit
annual statements indicating that each affected facility has been in
compliance. The annual reports for primer and topcoat operations would
also identify the number of times, if any, the pressure drop limits for
each filter or waterwash system were exceeded.
(3) Depainting Operations. If new non-chemical depainting
techniques are introduced to the facility since the filing of the
notification of compliance status or any subsequent semiannual report,
the EPA is proposing semiannual reports to identify these techniques.
The semiannual report would be required to identify any period of
malfunction of non-chemical depainting methods and techniques and any
period where the non-chemical depainting operation was not immediately
shut down when the pressure drop across the filters was out of range.
For periods of malfunction of non-chemical depainting methods,
semiannual reports would be required that identify the method or
technique that malfunctioned, the date that the malfunction occurred
and was corrected, a description of the malfunction, the alternative
method(s) used for depainting during the period of malfunction, and the
date(s) that the methods were begun and discontinued. This information
is necessary so that adequate documentation is available to ascertain
whether malfunctions were repaired within the 15 day limit.
In addition, the facility would be required to report on a
semiannual basis any new chemical strippers or changes to existing
formulations and the organic HAP content of each. A semiannual report
would also be required for each 24-hour period where organic HAP were
emitted from the depainting operation, other than from spot, radome, or
parts stripping or decal removal.
Finally, the semiannual report would be required to identify all
changes in the type of aircraft depainted at the facility and to
identify the parts normally removed for depainting separate from the
aircraft for each new type of aircraft depainted. This is important
because of the exemption being proposed for radomes and parts that are
normally removed prior to depainting the aircraft.
If the depainting operation has been in compliance for the annual
period, then an annual report would be required stating that the
depainting operation has been in compliance with the applicable
standards. An annual report would also be required whenever the
calculated annual average volume of organic HAP-containing strippers
used per aircraft for spot stripping and decal removal exceeded the
applicable limits. The annual report would also report the number of
times the pressure drop across the particulate filters used for the
control of inorganic HAP emissions from non-chemical depainting
operations exceeded the limits specified by the manufacturer.
(4) Handling and storage of waste. As discussed earlier, since an
exemption exists for RCRA-regulated wastes, it is important to know
which wastes are subject to RCRA and which are not. Since facilities
undergo change over time, it is possible that these designations may
change. Further, new waste streams may be created. Therefore,
semiannual reports are being proposed to track changes in the RCRA
status of existing wastes and new wastes. An annual report would be
required if no changes occurred in the RCRA status to the existing
waste streams and if no new waste streams were generated.
d. Other Reports. The only ``other reports'' in the proposed rule
are those that are required under the General Provisions, subpart A of
40 CFR part 63.16 Of particular note is the report required in
response to periods of startup, shutdown, and malfunction. When the
procedures used during such periods are completely consistent with the
plan, a report stating such is to be delivered or postmarked by the
thirtieth (30th) day following the end of each calendar half. If the
procedures are not completely consistent with the plan, an owner or
operator is to report the actions taken within 2 working days after
commencing actions inconsistent with the plan, followed by a letter
within 7 working days after the end of the event. The EPA is proposing
that for non-chemical depainting malfunctions only, that the owner or
operator report any plan inconsistency for dealing with the malfunction
within 24 hours after the inconsistent depainting technique is actually
utilized. This is different from ``after the end of the event'' because
owners or operators may be able to adjust their depainting schedule to
accommodate the time to repair a malfunction without the need to
implement their malfunction plan.
---------------------------------------------------------------------------
\1\6Ibid.
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I. Selection of Compliance Deadlines
The EPA proposes to allow affected sources the following time
periods after promulgation for compliance, as provided for in section
112(i) of the Act. All sources, whether uncontrolled or having in place
control systems or measures requiring upgrading to meet the new rule,
would be required to reach full compliance within 3 years after
promulgation of the rule. In addition, all affected sources must comply
with the compliance dates specified in Sec. 63.6 (b) and (c) of the
General Provisions, 40 CFR part 63, subpart A.17
---------------------------------------------------------------------------
\1\7Ibid.
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The EPA considered requiring earlier compliance to some parts of
the proposed standards. However, comments received from state agencies
indicated that there would be far less burden enforcing the standards
if there was a single compliance date. Multiple compliance dates would
make it difficult for agencies in states with numerous sources to keep
track of which standards applied to each facility and when compliance
would have to begin.
The EPA recognizes the need for the full three-year period for
facilities to come into compliance due to the nature of testing and
qualification necessary for sources such as hand-wipe cleaning
solvents, primers, topcoats, and chemical milling maskants. For all
these reasons, the EPA is proposing that all sources be allowed up to
three years after the date of promulgation of the rule to achieve
compliance.
The EPA is requesting comments, however, concerning alternative
compliance dates for certain pollution prevention and housekeeping
measures. Specifically, the EPA is considering a compliance date of 90
days after the effective date of the proposed standards for the
cleaning operation housekeeping measures in Sec. 63.744(a) of the
proposed rule, the use of enclosed containers for flush cleaning
solvents in Sec. 63.744(d), and the provisions for handling and storage
of waste in Sec. 63.748. The EPA is also considering a compliance date
of 180 days after the effective date of the proposed standards for the
spray gun cleaning provisions in Sec. 63.744(c).
J. Operating Permit Program
Under 40 CFR part 70, all major sources of HAP will be required to
obtain an operating permit. Emission limits, monitoring, and reporting
and recordkeeping requirements are typically scattered among numerous
provisions of State implementation plans (SIP's) or Federal
regulations. As discussed in the rule for the operating permit program,
this new permit program would include in a single document all of the
requirements that pertain to a single source. Once a state's permit
program has been approved, each aerospace facility that is a major
source within that state must apply for and obtain an operating permit.
If the state wherein the aerospace facility is located does not have an
approved permitting program, the owner or operator of an aerospace
facility must submit a part 71 permit application if requested under 40
CFR part 71.
K. Solicitation of Comments
The Administrator welcomes comments from interested persons on any
aspect of the proposed standards, and on any statement in the preamble
or the referenced supporting documents.
The proposed standards were developed on the basis of information
available. The Administrator is specifically requesting factual
information that may support either the approach taken in the proposed
standards or an alternate approach. To receive proper consideration,
documentation or data should be provided.
VI. Administrative Requirements
A. Public Hearing
A public hearing will be held, if requested, to discuss the
proposed standards in accordance with section 307(d)(5) of the Act.
Persons wishing to make an oral presentation on the proposed standards
for aerospace manufacturing and rework should contact the EPA at the
address given in the ADDRESSES section of this preamble. Oral
presentations will be limited to 15 minutes each. Any member of the
public may file a written statement before, during, or within 30 days
after the hearing. Written statements should be addressed to the Air
and Radiation Docket and Information Center address given in the
ADDRESSES section of this preamble, and should refer to Docket No. A-
92-20.
A verbatim transcript of the hearing and any written statements
will be available for public inspection and copying during normal
working hours at the EPA's Air and Radiation Docket and Information
Center in Washington, DC (see ADDRESSES section of this preamble).
B. Docket
The docket is an organized and complete file of all the information
submitted to or otherwise considered by the EPA in the development of
this proposed rulemaking. The principal purposes of the docket are: (1)
To allow interested parties to readily identify and locate documents so
that they can intelligently and effectively participate in the
rulemaking process, and (2) to serve as the record in case of judicial
review (except for interagency review materials) (section 307(d)(7)(A)
of the Act).
C. Executive Order 12866
Under Executive Order 12866 (58 FR 61736 (October 4, 1993)), the
EPA must determine whether the regulatory action is ``significant'' and
therefore subject to Office of Management and Budget (OMB) review and
the requirements of the Executive Order. The Order defines
``significant regulatory action'' as one that is likely to result in a
rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or state, local, or tribunal governments or
communities,
(2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another agency,
(3) Materially affect the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof, or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
Pursuant to the terms of Executive Order 12866, OMB has made the
determination that this action is not a ``significant regulatory
action'' within the meaning of the Executive Order. For this reason,
this action was not submitted to OMB for review.
D. Paperwork Reduction Act
The information collection requirements in this proposed rule have
been submitted for approval to OMB under the Paperwork Reduction Act,
44 U.S.C. 3501 et seq. An Information Collection Request (ICR) document
has been prepared by the EPA (ICR No. 1687.01) and a copy may be
obtained from Ms. Sandy Farmer, Information Policy Branch, EPA, 401 M
St., SW, (2136), Washington, DC 20460 or by calling (202) 260-2740.
The public reporting burden for this collection of information is
estimated to average 366 hours per respondent for the first year after
the date of promulgation of the rule, including time for reviewing
instructions, searching existing data sources, gathering and
maintaining the data needed, and completing and reviewing the
collection of information.
Send comments regarding the burden estimate or any other aspect of
this collection of information, including suggestions for reducing this
burden, to Chief, Information Policy Branch, 2136, U.S. Environmental
Protection Agency, 401 M St., SW., Washington, DC 20460; and to the
Office of Management and Budget, Washington, DC 20503, marked
``Attention: Desk Officer for the EPA.'' The final rule will respond to
any OMB or public comments on the information collection requirements
contained in this proposal.
E. Regulatory Flexibility Act
The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires the
EPA to consider potential impacts of proposed regulations on small
``entities.'' Since the proposed rule applies only to major sources as
defined in section 112(a) of the Act, the EPA certifies that there
would not be a significant impact on a substantial number of small
entities. Consequently, a regulatory flexibility analysis is not
required.
F. Clean Air Act Section 117
In accordance with section 117 of the Act, publication of this
proposal was preceded by consultation with appropriate advisory
committees, independent experts, and Federal departments and agencies.
The Administrator welcomes comment on all aspects of the proposed
regulation, including health, economic, technological, or other
aspects.
G. Regulatory Review
In accordance with sections 112(d)(6) and 112(f)(2) of the Act,
this regulation will be reviewed within 8 years from the date of
promulgation. This review may include an assessment of such factors as
evaluation of the residual health risk, any overlap with other
programs, the existence of alternative methods, enforceability,
improvements in emission control technology and health data, and the
recordkeeping and reporting requirements.
List of Subjects in 40 CFR Part 63
Air pollution control, Environmental protection, Hazardous
substances, Reporting and recordkeeping requirements.
VII. Statutory Authority
The statutory authority for this proposal is provided by sections
101, 112, 114, 116, and 301 of the Clean Air Act, as amended; 42
U.S.C., 7401, 7412, 7414, 7416, and 7601.
4Dated: May 25, 1994.
Carol M. Browner,
Administrator.
[FR Doc. 94-13561 Filed 6-3-94; 8:45 am]
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