[Federal Register: May 3, 2007 (Volume 72, Number 85)]
[Rules and Regulations]
[Page 25137-25159]
[DOCID:fr03my07-9]

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Part III

Environmental Protection Agency

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40 CFR Part 63

 National Air Emission Standards for Hazardous Air Pollutants:
Halogenated Solvent Cleaning; Final Rule

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2002-0009; FRL-8303-6]
RIN 2060-AK22

National Air Emission Standards for Hazardous Air Pollutants:
Halogenated Solvent Cleaning

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is promulgating revised standards to limit emissions of
methylene chloride (MC), trichloroethylene (TCE) and perchloroethylene
(PCE) from facilities engaged in halogenated solvent cleaning. On
December 2, 1994, EPA promulgated technology-based emission standards
to control HAP emissions of halogenated solvents from halogenated
solvent cleaning. Pursuant to the Clean Air Act (CAA) section 112(f),
EPA has evaluated the remaining risk to public health and the
environment following implementation of the technology-based rule and
is promulgating more stringent standards in order to provide an ample
margin of safety to protect public health. These final standards will
provide further reductions of MC, PCE, and TCE beyond the 1994 national
emission standards for hazardous air pollutants (NESHAP), through
application of a facility-wide total MC, PCE, and TCE emission
standard. In addition, EPA has reviewed the standards as required by
section 112(d)(6) of the CAA and has determined that, taking into
account developments in practices, processes, and control technologies,
no further action beyond what is required under CAA section 112(f) is
necessary at this time.

EFFECTIVE DATE: This final rule is effective May 3, 2007.

ADDRESSES: EPA has established a docket for this action under Docket ID
No. EPA-HQ-OAR-2002-0009. All documents in the docket are listed on the
http://www.regulations.gov Web site. Although listed in the index, some

information is not publicly available (e.g., Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute). Certain other material, such as copyrighted material, will
be publicly available only in hard copy form. Publicly available docket
materials are available either electronically through
http://www.regulations.gov or in hard copy at the EPA Docket Center, Docket ID

No. EPA-HQ-OAR-2002-0009, EPA West Building, Room B-102, 1301
Constitution Ave., NW., Washington, DC. This Docket Facility is open
from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal
holidays. The Docket telephone number is<PHONE_NUMBER>, and the
telephone number for the Air and Radiation Docket is<PHONE_NUMBER>.
EPA visitors are required to show photographic identification and sign
the EPA visitor log. After processing through the X-ray and
magnetometer machines, visitors will be given an EPA/DC badge that must
be visible at all times.
    Informational updates will be provided via the EPA Web site at
http://www.epa.gov/epahome/dockets.htm as they are available.

FOR FURTHER INFORMATION CONTACT: For questions about the final rule
amendments, contact Mr. H. Lynn Dail, EPA, Office of Air Quality
Planning and Standards, Sector Policies and Programs Division, Natural
Resources and Commerce Group (E143-03), Research Triangle Park, NC
27711; telephone number<PHONE_NUMBER>; fax number<PHONE_NUMBER>; e-
mail address<EMAIL_ADDRESS>For questions on the residual risk
analysis, contact Mr. Dennis Pagano, EPA, Office of Air Quality
Planning and Standards, Health and Environmental Impacts Division,
Sector Based Assessment Group (C539-02), Research Triangle Park, NC
27711; telephone number<PHONE_NUMBER>; fax number<PHONE_NUMBER>; e-
mail address<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Regulated Entities. Categories and entities
potentially regulated by the final rule include:

------------------------------------------------------------------------
                                                         Examples of
          Category               NAICS \1\ code          potentially
                                                     regulated entities
------------------------------------------------------------------------
Industry....................  Any of numerous       Operations at
                               industries using      sources that are
                               halogenated solvent   engaged in solvent
                               cleaning, primary     cleaning using MC,
                               affected industries   PCE, or TCE.
                               include those in
                               NAICS Codes
                               beginning with: 331
                               (primary metal
                               man.), 332
                               (fabricated metal
                               man.), 333
                               (machinery man.),
                               334 (computer and
                               electronic product
                               man.), 335
                               (electrical
                               equipment,
                               appliance, and
                               component man.);
                               336 (transportation
                               equipment man.);
                               337 (furniture and
                               related products
                               man.); and 339
                               (misc. man.).
Federal, State, local, and    ....................  Operations at
 tribal government.                                  sources that are
                                                     engaged in solvent
                                                     cleaning using MC,
                                                     PCE, or TCE.
------------------------------------------------------------------------
\1\ North American Industry Classification System.

    This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by the final
rule. This final rule directs an owner or operator of a facility that
is subject to the 1994 NESHAP for Halogenated Solvent Cleaning (40 CFR
63.460 of subpart T), to determine whether today's final standards
require the facility additionally to operate under the certain specific
emission limits. If you have any questions regarding the applicability
of the final rule to a particular entity, consult the person listed in
the preceding FOR FURTHER INFORMATION CONTACT section.
    Docket. The docket number for the National Emission Standards for
Hazardous Air Pollutants: Halogenated Solvent Cleaning (40 CFR part 63,
subpart T) is Docket ID No. EPA-HQ-OAR-2002-0009.
    Worldwide Web (WWW). In addition to being available in the docket,
an electronic copy of the final rule is also available on the http://WWW.

Following the Administrator's signature, a copy of the final rule will
be posted on EPA's Technology Transfer Network (TTN) policy and
guidance page for newly proposed or promulgated rules at http://www.epa.gov/ttn/oarpg.
 The TTN provides information and technology

exchange in various areas of air pollution control.
    Judicial Review. Under section 307(b)(1) of the Clean Air Act
(CAA), judicial review of the final rule is available only by filing a
petition for review in the U.S. Court of Appeals for the District of
Columbia Circuit by July 2, 2007. Under CAA section 307(d)(7)(B), only
an objection to the final rule that was raised with

reasonable specificity during the period for public comment can be
raised during judicial review. Moreover, under CAA section 307(b)(2),
the requirements established by this final action may not be challenged
separately in any civil or criminal proceedings brought by EPA to
enforce these requirements.
    Section 307(d)(7)(B) of the CAA further provides a mechanism for
EPA to convene a proceeding for reconsideration, ``if the person
raising the objection can demonstrate to the EPA that it was
impracticable to raise such an objection [within the period for public
comment] or if the grounds for such objection arose after the period
for public comment (but within the time specified for judicial review)
and if such objection is of central relevance to the outcome of the
rule.'' Any person seeking to make such a demonstration to the EPA
should submit a Petition for Reconsideration to the Office of the
Administrator, U.S. EPA, Room 3000, Ariel Rios Building, 1200
Pennsylvania Ave., NW., Washington, DC 20460, with a copy to both the
person(s) listed in the preceding FOR FURTHER INFORMATION CONTACT
section, and the Associate General Counsel, Air and Radiation Law
Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200
Pennsylvania Ave., NW., Washington, DC 20004.
    Outline. The information presented in this Preamble is organized as
follows:

I. Background
    A. What is the statutory authority for this action?
    B. What is halogenated solvent cleaning?
    C. What are the health effects of halogenated solvent cleaning?
    D. What does the 1994 halogenated solvent cleaning NESHAP
require?
II. Summary of the Proposed Rule
    A. Issuance of the Notice of Data Availability (NODA)
III. Summary of the Final Rule
    A. What does the final rule require?
    1. What are the requirements for halogenated solvent cleaning
machines?
    2. What are the requirements for halogenated solvent cleaning
machines at military depot maintenance facilities?
    3. What are the requirements for continuous web cleaners and
halogenated solvent cleaning machines at narrow tube manufacturing
and aerospace industries?
    B. What is the rationale for the final rule?
    1. Revision of the Baseline Risk Estimate
    2. Rationale for the 60,000 kg/yr MC Equivalent Emission Limit
    3. Rationale for the Requirements for Halogenated Solvent
Cleaning Machines at Military Depot Maintenance Facilities.
    4. Rationale for Our Decisions Regarding Continuous Web Cleaners
and Halogenated Solvent Cleaning Machines at Narrow Tube
Manufacturing and Aerospace Facilities
    C. What is the compliance schedule?
    D. What is the final decision on the applicable unit risk value?
    E. What is EPA's finding on the Section 112(d)(6) review
requirements?
IV. Responses to Significant Comments
    A. Significant Comments on the Proposal
    1. Emission Limit Option 1 or Option 2
    2. Equation for MC Equivalents
    3. Use of CalEPA or OPPTS URE for Implementation of the Emission
Limit
    4. Compliance Deadline
    5. Applicability of Control Requirements
    6. Costs Associated With Compliance
    7. General Comments
V. Responses to Significant Comments on EPA's December 14, 2006,
Notice of Data Availability (NODA)
    A. Emission Limits
    B. Cost Impacts
    C. Compliance Schedule
VI. Impacts
VII. Statutory and Executive Order Reviews
    A. Executive Order 12866: Regulatory Planning and Review
    B. Paperwork Reduction Act
    C. Regulatory Flexibility Act
    D. Unfunded Mandates Reform Act
    E. Executive Order 13132: Federalism
    F. Executive Order 13175: Consultation and Coordination With
Indian Tribal Governments
    G. Executive Order 13045: Protection of Children From
Environmental Health and Safety Risks
    H. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use
    I. National Technology Transfer Advancement Act
    J. Congressional Review Act

I. Background

A. What is the statutory authority for this action?

    Section 112 of the CAA establishes a comprehensive regulatory
process to address emissions of hazardous air pollutants (HAP) from
stationary sources. In accordance with CAA section 112(c), EPA
identifies categories and subcategories of sources emitting one or more
of the HAP listed in CAA section 112(b). CAA section 112(d) then
requires us to promulgate national technology-based emission standards
for each category of sources that emits or has the potential to emit
any single HAP at a rate of ten tons or more per year or any
combination of HAP at a rate of 25 tons or more per year (known as
``major sources''), as well as for certain area sources emitting less
than those amounts. For major sources, these technology-based standards
must reflect the maximum reductions of HAP achievable (after
considering cost, energy requirements, and non-air health and
environmental impacts) and are commonly referred to as maximum
achievable control technology (MACT) standards. For area sources, CAA
section 112(d)(5) provides that the standards may reflect generally
available control technology or management practices in lieu of MACT,
and are commonly referred to as generally available control technology
(GACT) standards.
    In what we refer to as the ``technology review'', CAA section
112(d)(6) then requires EPA to review the CAA section 112(d) standards
and to revise them ``as necessary, taking into account developments in
practices, processes and control technologies,'' no less frequently
than every 8 years.
    The residual risk review is described in section 112(f) of the CAA.
EPA prepared a Report to Congress discussing (among other things)
methods of calculating risk posed (or potentially posed) by sources
after implementation of the MACT standards, the public health
significance of those risks, the means and costs of controlling them,
actual health effects to persons in proximity to emitting sources, and
recommendations as to legislation regarding such remaining risk. The
EPA prepared and submitted this report (``Residual Risk Report to
Congress,'' EPA-453/R-99-001) in March 1999. The Congress did not act
on any of the recommendations in the report; thereby, triggering the
second stage of the standard-setting process, the residual risk phase.
    CAA section 112(f)(2) requires us to determine whether additional
standards are ``required in order to provide an ample margin of safety
to protect public health.'' If the MACT standards for a HAP
``classified as a known, probable, or possible human carcinogen do not
reduce lifetime excess cancer risks to the individual most exposed to
emissions from a source in the category or subcategory to less than 1-
in-a-million,'' EPA must promulgate residual risk standards for the
source category (or subcategory) as necessary to provide an ample
margin of safety. EPA's framework for making ample margin of safety
determinations under CAA section 112(f)(2) is provided in the Benzene
NESHAP (54 FR 38044, September 14, 1989) which was codified by Congress
in CAA section 112(f)(2)(B). The EPA also must promulgate more
stringent standards to prevent an adverse environmental effect (defined
in CAA section 112(a)(7) as ``any significant and widespread adverse
effect * * * to wildlife, aquatic life, or other natural resources,
including adverse impacts on populations of endangered or threatened
species or significant degradation of environmental quality over broad

areas.''), but must consider costs, energy, safety, and other relevant
factors in doing so.

B. What is halogenated solvent cleaning?

    Halogenated solvent cleaning machines use the halogenated solvents
methylene chloride (MC), perchloroethylene (PCE), trichloroethylene
(TCE), or 1,1,1,-trichloroethane (TCA) and halogenated solvent blends
or their vapors to remove soils such as grease, oils, waxes, carbon
deposits, fluxes, and tars from metal, plastic, fiberglass, printed
circuit boards, and other surfaces. Halogenated solvent cleaning is
typically performed prior to processes such as painting, plating,
inspection, repair, assembly, heat treatment, and machining. Types of
solvent cleaning machines include, but are not limited to, batch vapor,
in-line vapor, in-line cold, and batch cold solvent cleaning machines.
Buckets, pails, and beakers with capacities of 7.6 liters (2 gallons)
or less are not considered solvent cleaning machines.
    Halogenated solvent cleaning does not constitute a distinct
industrial category, but is an integral part of many major industries.
The five 3-digit NAICS Codes that use the largest quantities of
halogenated solvents for cleaning are NAICS 337 (furniture and related
products manufacturing), NAICS 332 (fabricated metal manufacturing),
NAICS 335 (electrical equipment, appliance, and component
manufacturing), NAICS 336 (transportation equipment manufacturing), and
NAICS 339 (miscellaneous manufacturing). Additional industries that use
halogenated solvents for cleaning include NAICS 331 (primary metals),
NAICS 333 (machinery), and NAICS 334 (electronic equipment
manufacturing). Non-manufacturing industries such as railroad (NAICS
482), bus (NAICS 485), aircraft (NAICS 481), and truck (NAICS 484)
maintenance facilities; automotive and electric tool repair shops
(NAICS 811); and automobile dealers (NAICS 411) also use halogenated
solvent cleaning machines. We estimated that there were approximately
16,400 batch vapor, 8,100 in-line, and perhaps as many as 100,000 batch
cold cleaning machines in the U.S. prior to promulgation of the MACT
standards. More recent information shows that the current number of
cleaning machines is much lower than these pre-MACT estimates. We
currently estimate the number of sources in this source category to be
about 3,800 cleaning machines located at 1,900 facilities in the U.S.
This estimate is based on information we collected in 1998 and reflects
the decreases in HAP emissions and demand that were expected due to
implementation of MACT control technologies and work practice
standards. Information suggesting that further decreases in solvent
usage and therefore, solvent emissions, have occurred in the post-MACT
implementation years may reflect that either the number of sources in
the source category have declined or that sources are implementing
methods to recycle more solvent, resulting in reduced emissions and
some cost savings.
    ``Solvent cleaning machine'' is defined in the Federal Register, 40
Code of Federal Regulations (CFR) Sec.  63.461. Solvent cleaning
machine types such as batch cleaners and in-line cleaners are also
described. Both cleaner types can be designed to use either solvent at
room temperature (cold cleaners) or solvent vapor (vapor cleaners).
    Continuous web cleaners are a subset of in-line cleaners that are
used to clean products such as films, sheet metal, and wire in rolls or
coils. The workload is uncoiled and conveyorized throughout the
cleaning machine at speeds in excess of 11 feet per minute and recoiled
or cut as it exits the machine. Emission points from continuous
cleaners are similar to emission points from other inline cleaners.
Continuous cleaners are semi-enclosed, with emission points where the
workload enters and exits the machine. Squeegee rollers reduce carry
out emissions by removing excess solvent from the exiting workload.
Some continuous machines have exhaust systems similar to those used
with some other in-line cleaners.

C. What are the health effects of halogenated solvent cleaning?

    MC, PCE, TCA, and TCE are the primary halogenated solvents used for
solvent cleaning. The health effects of these four solvents were
described in the proposed rule of August 17, 2006 (71 FR 47680), which
is available for review in docket EPA-HQ-OAR-2002-0009. All four
produce acute and/or chronic non-cancer health effects at sufficient
concentrations; three of the four have been classified as probable or
possible human carcinogens by either EPA or other governmental or
international agencies. Carbon tetrachloride and chloroform are no
longer used as degreasing solvents; therefore, their health effects
were not discussed in the proposed rule.
    The Agency's Integrated Risk Information System's (IRIS)
toxicological reviews of PCE, TCE and MC are currently being developed
or revised. The current schedule indicates that the new or final IRIS
toxicological reviews of the carcinogens PCE, TCE and MC are not
expected until late 2008 for PCE, mid 2009 for MC, and late 2010 for
TCE. A publicly available draft revised toxicological review of the
non-carcinogenic HAP TCA, has been released for external peer review. A
final revised IRIS toxicological review of TCA is not expected until
late 2007. The National Research Council (NRC) released a report in
2006 that described their findings after a comprehensive review of the
health effects of TCE, focusing on critical issues in developing an
objective, realistic, and scientifically based health risk assessment
for TCE. This report is available at http://www.nas.edu/catalog/11707.html.
 Toxicity or status information for the four HAPs may be

obtained from the following Web sites: EPA's Toxicity database at
http://www.epa.gov/ttn/atw/toxsource/table1.pdf shows the benchmarks

for the four HAPs used in the risk assessment. Specific information
underlying the values used may be found at the following locations:
California EPA's Web site at http://www.oehha.ca.gov/air/hot_spots/index.html
 has the background information on PCE and TCE used to

develop the cancer potency values.
    The Agency for Toxic Substances and Disease Registry's Web site at
http://www.atsdr.cdc.gov/toxpro2.html has the background information

used to develop the non-cancer values for MC and PCE.
    EPA's IRIS Web site at http://www.epa.gov/iris/index.html provides

the information supporting the cancer potency value for MC.
    Status reports for IRIS chemical reassessments, (i.e., TCA) are
available at http://cfpub.epa.gov/iristrac/index.cfm.

D. What does the 1994 halogenated solvent cleaning NESHAP require?

    On December 2, 1994, we promulgated national emission standards for
halogenated solvent cleaning (59 FR 61801, (December 2, 1994)) and
required existing sources to comply with the national emission
standards by December 2, 1996.
    The promulgated standards in 40 CFR Subpart T include multiple
alternatives to allow owners or operators maximum compliance
flexibility. The final rules for the halogenated solvent cleaning
source category are available in the docket, EPA-HA-OAR-2002-0009.

II. Summary of the Proposed Rule

    The August 17, 2006 proposed rule would have required all owners
and

operators of halogenated solvent cleaning machines that are subject to
the 1994 NESHAP (40 CFR Part 63, subpart T), except for cold batch area
source cleaning machines subject to GACT, to comply with a facility-
wide solvent emission limit, summarized in Table 1 of this Preamble. As
proposed, the standards would be in addition to the requirements of the
1994 NESHAP.
    Specifically, we co-proposed two facility-wide emission limits for
facilities that use multiple HAP solvents, 25,000 kg/yr and 40,000 kg/
yr of MC equivalent emissions, and solicited comments on which of these
two options would be the most appropriate. We developed a method for
facilities using multiple HAP solvents to determine their emission
limit by calculating their MC-equivalent emissions using the toxicity-
weighting equation, which is shown as equation 1, below. We proposed
that where more than one halogenated solvent is used at a facility, the
owner or operator would be required to calculate the facility's
weighted halogenated solvent cleaning emissions using equation 1 and to
comply with the limit in the last row of Table 1 of this Preamble. For
owners or operators of facilities that use a single halogenated solvent
(MC, TCE or PCE), we proposed that the owner or operator of each
affected facility would be required to ensure that its emissions of the
single halogenated solvent would not exceed the single-solvent limits
specified in Table 1 of this Preamble.

                     Table 1.--Summary of the Proposed Facility-Wide Annual Emission Limits
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                                                                 Proposed facility-wide   Proposed facility-wide
                       Solvents emitted                          annual emission limits   annual emission limits
                                                                   in kg/yr--option 1       in kg/yr--option 2
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PCE only......................................................   \a\ 3,200 \b\ (26,700)   \a\ 2,000 \b\ (16,700)
TCE only......................................................                   10,000                    6,250
MC only.......................................................                   40,000                   25,000
Multiple solvents--Calculate the MC-weighted emissions using                     40,000                  25,000
 equation 1...................................................
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\a\ PCE emission limit calculated using California EPA (CalEPA) Unit Risk Estimate (URE).
\b\ PCE emission limit calculated using the EPA Office of Prevention, Pesticides and Toxic Substances (OPPTS)
  Unit Risk Estimate (URE).

    Equation 1:

(kgs/yr of PCE emissions x A)+(kgs/yr of TCE emissions x B) + (kgs/yr
of MC emissions) = MC weighted emissions in kgs/yr

    In equation 1, the facility emissions of PCE and TCE are weighted
according to their carcinogenic potency relative to that of MC. Thus,
``A'' in the equation is the ratio of the cancer unit risk estimate
(URE) for PCE to the URE for MC, and the ``B'' in the equation is the
ratio of the URE for TCE to the URE for MC. Because the IRIS assessment
for PCE is in process, we requested comment on the use of the CalEPA
URE, the OPPTS URE, or other values in deriving the PCE emission limit
for the final rule. See 71 FR 47680. As explained in our proposal, the
value of ``A'' would be 1.5 or 12.5, depending on whether we used the
OPPTS URE or the CalEPA URE value for PCE. The value for ``B'' is 4.25.
At proposal, we stated that there may be other approaches for deriving
emissions standards for facilities that use multiple HAP. We requested
comment on other possible methods for establishing emission limits at
facilities using more than one of the listed HAP solvents.
    Further, at proposal we presented and discussed our evaluation of
four other emission limits that would reduce residual risk. These
emission limits are summarized below:
     100,000 level--Sources would reduce MC-equivalent
emissions to no more than 100,000 kg/yr (220,000 lbs/yr).
     60,000 level-- Sources would reduce MC-equivalent
emissions to no more than 60,000 kg/yr (132,000 lbs/yr).
     15,000 level-- Sources would reduce MC-equivalent
emissions to no more than 15,000 kg/yr (33,000 lbs/yr).
     6,000 level--Sources would reduce MC-equivalent emissions
to no more than 6,000kg/yr (13,200 lbs/yr).

See 71 FR 47680-81 for further discussion of these four emission
levels.
    We proposed a compliance deadline of two years after the effective
date of the final rule for existing sources by resolving the seemingly
conflicting provisions of section 112(f)(4)(A) and 112(i), and by
determining that CAA section 112(i) was the controlling provision for
compliance deadlines for existing sources with regard to standards
promulgated under CAA section 112(f)(2). This proposal was based on our
belief that the proposed compliance date was realistic for any affected
facility that has to plan a control strategy, purchase and install the
control device(s), and bring the control device(s) online.
    See 71 FR 47683-84 for a complete discussion of the proposed
facility-wide solvent emission limit, compliance options, and our
rationale for proposing the facility-wide solvent emission limit.

A. Issuance of the Notice of Data Availability (NODA)

    We received comments on the proposed rule from industry, states,
solvent manufacturers, industry associations and district air
associations. Industry's comments were primarily submitted by four
specific sectors: Narrow tubing manufacturing facilities, facilities
that manufacture specialized products requiring continuous web
cleaning, aerospace manufacturing and maintenance facilities, and
military depot maintenance facilities. Additional comments were
submitted by facilities that use multiple halogenated solvent cleaning
machines. Comments and data submitted by the four industry sectors
focused on the unique nature and size of the halogenated solvent
cleaning machines they use in their cleaning operations. These data and
information were otherwise not available to EPA at proposal. The
commenters expressed concern about their ability to comply with the
proposed emission limits because of technical and economic
difficulties. They also expressed an inability to meet the proposed
compliance deadline. Based on these comments and our desire to
reconcile these concerns, we issued a Notice of Data Availability
(NODA) on December 14, 2006 (71 FR 75182). In addition, in order to
have adequate time to address these concerns, we asked for and received
an extension of our December 15, 2006 court-ordered promulgation
deadline to April 16, 2007. The NODA was intended to gather more
information, especially from these four industry sectors, on the
availability of technology or methods to meet the proposed emission
limits, the costs to achieve the proposed emission limits, and the time
required to achieve the proposed emission limits.

    As a result of the NODA, EPA received significant comments from
responders associated with the above-noted industries, industry
associations, and commenters that were not associated with the above-
noted industries. They provided additional data and information that
were directly relevant to the promulgation of the proposed facility-
wide emission limits. These data and information were otherwise not
available to EPA at proposal. A more complete description of the
comments received may be found in section V of this Preamble and in the
docket for this rule.

III. Summary of Final Rule

A. What does the final rule require?

    Using the data from comments on the proposal and NODA, we re-
evaluated the costs and technical feasibility of complying with the
proposed emission limits. The re-analysis resulted in a final rule that
changed from what we proposed, especially for four industry sectors:
narrow tubing manufacturing facilities, facilities that manufacture
specialized products requiring continuous web cleaning, aerospace
manufacturing and maintenance facilities, and military depot
maintenance facilities.
1. What are the requirements for Halogenated Solvent Cleaning Machines?
    EPA is promulgating a facility-wide emission limit of 60,000 kg/yr
MC equivalent, as shown in Table 2 of this Preamble, applicable to all
existing halogenated solvent cleaning machines with the exception of
halogenated solvent cleaning machines used by the following industries:
Facilities that manufacture narrow tubing, facilities that manufacture
specialized products requiring continuous web cleaning, aerospace
manufacturing and maintenance facilities, and military depot
maintenance facilities.
    This final rule also requires owners or operators of halogenated
solvent cleaning machines that use any one of the halogenated solvents
covered by this rule (i.e., MC, PCE or TCE), with the exception of the
halogenated solvent cleaning machines used by the above-noted
industries, to ensure that facility-wide solvent emissions from all
halogenated solvent cleaning activities are less than or equal to the
limit for the single halogenated solvent specified in Table 2 of this
Preamble.
    This final rule also requires halogenated solvent cleaning machines
that are constructed or reconstructed after August 17, 2006, with the
exception of halogenated solvent cleaning machines associated with the
above-noted industries, to comply with the 60,000 kg/yr MC equivalent
emission limit upon the effective date of this rule or upon startup,
whichever occurs later. The revised requirements apply in addition to
the 1994 NESHAP.
    For area sources subject to the 1994 NESHAP and constructed or
reconstructed after August 17, 2006, the final rule revisions add to
the previous 1994 NESHAP by requiring implementation of the 60,000 kg/
yr MC equivalent facility-wide emission limit upon the effective date
of this rule or upon startup, whichever occurs later. This final rule
also limits the use of any one of the halogenated solvents covered by
this rule (i.e., MC, PCE or TCE), at area sources, to the limits for
the single halogenated solvent specified in Table 2 of this Preamble.
The area sources in the halogenated solvent cleaning source category
that are subject to GACT are not subject to these additional standards.
These area sources are cold batch cleaning machines.
    When a facility's total halogenated solvent emissions from its
degreasing operations exceed the applicable emission limits, the
facility must implement means to comply with these amended standards.
In addition, under this final rule, the 1994 NESHAP requirements for
all halogenated solvent cleaning machines remain applicable. Compliance
with the 60,000 kg/yr MC equivalent emission limit is demonstrated by
determining the annual PCE, TCE, and MC emissions for all cleaning
machines at the facility, using Equation 1 as necessary, and comparing
to the emission limits in Table 2.
    There are no other additional equipment monitoring or work practice
requirements associated with the facility-wide annual emissions limit.
Annual emissions of PCE, TCE, and MC are determined based on records of
the amounts and dates of the solvents added to cleaning machines during
the year, the amounts and dates of solvents removed from cleaning
machines during the year, and the amounts and dates of the solvents
removed from cleaning machines in solid waste. Records of the
calculation sheets showing how the annual emissions were determined
must be maintained. A facility will determine compliance with the
standards by comparing their annual MC-equivalent emissions to the
limits specified in Table 2 of this final rule.

                          Table 2.--Summary of the Facility-Wide Annual Emission Limits
----------------------------------------------------------------------------------------------------------------
                                                                     Final general
                                                                  halogenated solvent         Final military
                       Solvents emitted                          cleaning facility-wide   maintenance facility-
                                                                 annual emission limits    wide annual emission
                                                                        in kg/yr             limits in kg/yr
----------------------------------------------------------------------------------------------------------------
PCE only......................................................                    4,800                    8,000
TCE only......................................................                   14,100                   23,500
MC only.......................................................                   60,000                  100,000
Multiple solvents--Calculate the MC-weighted emissions using                     60,000                  100,000
 equation 1...................................................
----------------------------------------------------------------------------------------------------------------

    Equation 1:

(kgs/yr of PCE emissions x A)+(kgs/yr of TCE emissions x B) + (kgs/yr
of MC emissions) = MC weighted Emissions in kgs/yr

    In this equation, the facility emissions of PCE and TCE are
weighted according to their carcinogenic potency relative to that of
MC. Thus, ``A'' in the equation is the ratio of the URE for PCE to the
URE for MC, and the ``B'' in the equation is the ratio of the URE for
TCE to the URE for MC. The value of ``A'' is 12.5 (see section C
below). The value for ``B'' is 4.25.
2. What are the requirements for halogenated solvent cleaning machines
at military depot maintenance facilities?
    For existing halogenated solvent cleaning machines in use at
military depot maintenance facilities where multiple halogenated
solvents are emitted, the final rule sets a facility-wide emission
limit of 100,000 kg/yr of MC equivalent emissions as indicated in Table
2 of this Preamble. This final rule also limits the use of any one of
the halogenated solvents covered by this rule (i.e., MC, PCE or TCE),
to the limits for the single halogenated solvent specified in Table 2
of this Preamble. In

addition, the 1994 NESHAP requirements remain applicable.
    For halogenated solvent cleaning machines that are constructed or
reconstructed after August 17, 2006 and that are used at military depot
maintenance facilities, the final rule revisions add to the previous
1994 NESHAP by requiring implementation of the 100,000 kg/yr MC
equivalent emission limit upon the effective date of this rule or upon
startup, whichever occurs later.
    Military Depot Maintenance Facilities are Government-owned
industrial centers that operate solely for the purpose of repairing,
modifying, converting and refitting worn and/or damaged military assets
for redistribution to military units and are subject to the 1994
NESHAP. Depot level maintenance includes the repair, fabrication,
manufacture, rebuilding, assembly overhaul, modification,
refurbishment, test, analysis, repair-process design, in-service
engineering, upgrade, painting and disposal of parts, assemblies,
subassemblies, software, components, or end items that require
industrial shop facilities, tooling, support equipment, and/or
personnel of higher technical skills, or processes beyond the military
installation's organizational level capability.
3. What are the requirements for continuous web cleaners and
halogenated solvent cleaning machines at narrow tube manufacturing and
aerospace facilities?
    The requirements set forth in this final rule are not applicable to
continuous web cleaning machines, halogenated solvent cleaning machines
that are located at narrow tubing manufacturing facilities, and the
aerospace manufacturing and maintenance industry and facilities. Narrow
tube manufacturing facilities primarily engage in the production of
small diameter (mechanical and hypodermic size) cold drawn metallic,
seamless tubes from materials such as stainless steel, nickel alloys,
titanium and its alloys, and alloys of zirconium with a portion of the
outside diameters 1/4'' or less (a subset of NAICS 331210), and are
subject to the 1994 NESHAP. Aerospace manufacturing and maintenance
facilities manufacture, rework, or repair aircraft such as airplanes,
helicopters, missiles, rockets, and space vehicles, and are subject to
the 1994 NESHAP. The 1994 NESHAP requirements remain applicable to all
the continuous web and halogenated solvent cleaning machines associated
with the above-noted facilities.
    For the above-noted facilities, we are adopting no changes to the
1994 NESHAP under CAA Section 112(f) because the current level of
control called for by the existing NESHAP reduces HAP emissions to
levels that present an acceptable level of risk, protects public health
with an ample margin of safety, and prevents any adverse environmental
effects. The finding regarding an ``ample margin of safety'' is based
on a consideration of the additional costs of further control as
represented by compliance with emissions limits adapted for each
industry sector, considering availability of technology, costs and time
to comply with further controls (see Section III.B., below for a
discussion of our rationale for this final rule).

B. What is the rationale for the final rule?

    Based on comments and data received on both the proposal and the
NODA, we re-evaluated the risk, the technical feasibility, the costs of
the proposed options, and the compliance time needed to implement the
proposed options. This re-analysis focused especially on the four
industry sectors discussed above. Additionally, in response to public
comments we updated the risk assessment for the entire source category
using the 2002 National Emissions Inventory (NEI) database, which was
not available for the proposal. The following rationale presents the
results of our re-analysis of the data.
1. Revision of the Baseline Risk Estimate
    Based on public comment, we used the 2002 NEI inventory to re-
analyze the risk from this source category. The resulting re-analysis
of risk at the baseline emission level (i.e., the level of emissions
allowed by the 1994 MACT) indicated that the maximum individual cancer
risk (MIR) associated with this source category is 100-in-a-million
with an annual cancer incidence of 0.55. This is as compared to the
200-in-a-million MIR and 0.40 annual cancer incidence level that we
presented at proposal, which was based on the 1999 NEI database. We
consider both MIR values to be acceptable levels of maximum individual
risk considering the number of people exposed at these levels and the
absence of other adverse human and environmental health effects. We
note that the MIR of 100-in-a-million (calculated using the 2002 NEI
data) is the same regardless of the URE for PCE chosen for the risk
analysis (i.e., the CalEPA value or the OPPTS value, which results were
contrasted at proposal). This is because PCE is not the only driver of
the MIR risk level for the highest risk facilities.
    Given the uncertainties associated with the development of emission
inventories, neither the 1999 nor the 2002 NEI inventory should be
considered as correct in an absolute sense or as suggesting temporal
trends in degreasing machine populations or emissions. Rather, we
consider them to be ``snapshots'' of the true long-term inventory of
emissions for this source category, each carrying its own degree of
uncertainty. As such, the derived risk assessment results compared
above should be regarded as ranges within which the true risk metrics
are likely to fall.
    The revised population risk distribution at baseline emission
levels shows that about 25 people are exposed to the MIR risk level,
about 22,000 people are at estimated risks of >= 10-in-a-million risk
level, and about 4,000,000 people are at estimated risks of >= 1-in-a-
million. This is compared to approximately 90 people exposed to risks
at the MIR level (200-in-a-million), about 42,000 people at estimated
risks of >= 10-in-a-million risk level, and about 6,000,000 people at
estimated risks of >= 1-in-a-million that we presented at proposal.
Similar to the MIR and annual cancer incidence metrics, these values
may be an indication of the uncertainty presented by the databases
because, as earlier explained, both inventories are ``snapshots'' of
the industry rather than an absolute reflection of the ``current''
state of the industry.
    We did not reassess the environmental risks using the 2002 NEI
inventory but believe that no ``adverse environmental effects,'' as
defined in CAA section 112(a)(7), would occur given the similarities of
the human health risk results between the 1999 NEI data and 2002 NEI
data and the fact that we showed in the proposal that no adverse
environmental effects would likely occur using the 1999 NEI inventory.
2. Rationale for the 60,000 kg/yr MC Equivalent Emission Limit
    EPA is promulgating a facility-wide emission limit of 60,000 kg/yr
(MC equivalent emissions) applicable to emissions from all new and
existing halogenated solvent cleaning machines that are subject to the
1994 NESHAP, with the exception of halogenated solvent cleaning
machines used by the following industry sectors: Narrow tubing
manufacturing, facilities that manufacture specialized products
requiring continuous web cleaning, aerospace manufacturing and
maintenance, military depot

maintenance operations, and cold batch cleaning machines (which are
subject to GACT). Area sources operating halogenated solvent cleaning
machines that are subject to GACT also are not required to comply with
the facility-wide emission limits. This final rule reflects our
decision that the 60,000 kg/yr MC equivalent emission limit from the
August 17, 2006 proposal provides an ample margin of safety to protect
public health and prevents adverse environmental effects.
    In response to public comments received on our proposal and
subsequent NODA, we re-examined the data and assumptions used to
estimate the risk and compliance costs presented in the Preamble to our
proposed rule. We determined that certain significant data and
assumptions that we used to develop our cost estimates at proposal were
either no longer relevant, not reflective of more recent inventory
data, or not valid. As a result, we re-evaluated risks using the more
recent inventory data and modified our cost estimates in response to
public comment. The most important change we made is that we re-
analyzed the risk metrics and costs using the halogenated solvent
cleaning facilities in the finalized 2002 NEI, but removing facilities
in four specific industry sectors--aerospace manufacture and
maintenance facilities, narrow tube manufacturing facilities,
facilities using continuous web cleaning machines, and military
equipment maintenance facilities--from the database for the purpose of
estimating the risks and compliance costs associated with the remaining
facilities (Sections III.A.3 and III.B.3 explain our rationale for
removing the facilities in these industry sectors from this analysis).
    Other changes we made to our cost estimates in response to public
comment are as follows:
     We used the finalized 2002 NEI database containing
facility and emissions data as the source of our baseline emissions
estimates. We removed aerospace manufacture and maintenance facilities,
narrow tube manufacturing facilities, facilities using continuous web
cleaning machines, and military equipment maintenance facilities from
the database for the purpose of estimating the compliance costs for the
remaining facilities. (Sections III.A.3 and III.B.3 explain our
rationale for removing these facilities from this analysis.)
     We changed our assumptions about the percent reductions in
emissions that can be achieved by vacuum-to-vacuum machines from 97
percent to 95 percent.
     In the proposal, we assigned no operation and maintenance
cost to vacuum-to-vacuum machines. Based on public comment, our cost
estimates for this final rule incorporate annual operation and
maintenance costs of $18,832 for each machine.
     We updated the cost per gallon of PCE and TCE based on
information provided by commenters representing manufacturers of
solvents and the narrow tube manufacturing industry.
     We added a carbon adsorption device (CAD) option that
assumes a 30 percent control in emissions. We did not have this option
in the cost assumptions we made at proposal. We received comments that
this option may be available for some industries but that it is at
least ten times more expensive than the retrofit options we costed for
the proposal.
     We reduced the number of units for which solvent switching
could be a compliance option from 30 percent, used in the proposal, to
15 percent. We also corrected our method for calculating the emission
reduction impacts and solvent savings associated with solvent
switching.
    After re-assessing the risk and calculating revised cost estimates,
we re-examined our decision as to what level of control is necessary to
provide an ample margin of safety to protect human health and to
prevent adverse environmental effects, as required by the second step
of the residual risk process under CAA section 112(f)(2). We considered
the re-assessed risk estimates and the other health information along
with additional factors consistent with the 1989 Benzene NESHAP (54 FR
38044, September 14, 1989), such as cost, technological feasibility,
uncertainties and other relevant factors as discussed at proposal. We
re-analyzed the risk metrics using the halogenated solvent cleaning
facilities in the 2002 NEI, but removing aerospace manufacture and
maintenance facilities, narrow tube manufacturing facilities,
facilities using continuous web cleaning machines, and military depot
maintenance facilities.
    At proposal we had presented two options for emission limits that
would apply to all facilities in the category subject to the 1994 MACT
standards--25,000 kg/yr MC equivalent and 40,000 kg/yr MC equivalent.
We estimated that the 25,000 kg/yr limit would result in an emissions
reduction of 6,778 tons/year, thereby reducing the MIR to 10-in-a
million and reducing cancer incidence by 0.14-0.27 cases annually
(depending on which URE we use for PCE), at an annual cost savings of
$4.9 million annually or a cost savings of $724/ton HAP reduced.
Comments received included support for and against this level of
emissions reduction. Similarly, at proposal we estimated that applying
the 40,000 kg/yr limit to facilities in the entire source category
would result in an emissions reduction of 5,911 tons/yr, reducing the
MIR to 20-in-a million and reducing cancer incidence by 0.12-0.23 cases
annually, at an annual cost savings of $5.9 million annually or a cost
savings of $1,000/ton HAP reduced.\1\
---------------------------------------------------------------------------

    \1\ In considering these revised cost estimates, it should be
noted that there may be inherent uncertainties or anomalies in the
availability of information that underlie our costs for our options,
regardless of whether the estimates be positive costs or net cost
savings. There may also be other factors that are not reflected in
these estimates, however. For example, these estimates are largely
based on a 15-year equipment life for existing affected cleaners
(20-year for new cleaners) and a discount rate of 7 percent. If
industry determines that a shorter equipment life for the controls
considered in this analysis is appropriate based on perceived
uncertainty of future availability of these solvents, then the
opportunity cost of capital will be higher and our estimates of net
cost savings may be altered. If these controls are in operation
longer than expected by industry, however, then a longer equipment
life would be appropriate and our estimates of costs, which may be
net costs or net savings, may also be altered.
---------------------------------------------------------------------------

    In developing the final rule, we initially re-examined the 25,000
kg/yr and 40,000 kg/yr levels of control for the subset of the category
that excludes the four specific industry sectors identified above,
using costing assumptions revised based on public comment as described
above. This re-analysis uses the 2002 NEI data rather than the 1999 NEI
data used in the proposal. We observed that although the overall
reductions in MIR and cancer incidence at these levels would be similar
to those estimated at proposal for the entire category, the substantial
cost savings estimated at proposal would change to a net cost for both
emission limits. This is a result of both our use of certain cost
assumptions at proposal that have been amended for analyzing the cost
of the final rule and the fact that four industry sectors are now being
considered separately in this final rule. Specifically, for the 25,000
kg/yr limit, our analysis of the subset of the category that excludes
the four specific industry sectors shows the same reduction in MIR (to
10-in-a-million) and similar estimated reduction in cancer incidence,
0.24 cases annually, as we showed at proposal. In contrast, our cost
analysis for this subset of the source category shows a total
annualized cost (not savings) of about $1.2 million, or a cost of about
$520 per ton HAP reduced (we estimate 2,351 tons HAP reduced at this
level). Similarly, for the 40,000 kg/yr limit, our revised analysis
shows the

same reduction in MIR (to 20-in-a-million), and a similar estimated
reduction in cancer incidence, 0.21 cases annually, as we showed at
proposal, but at an annualized cost (not savings) of $130,000, or a
cost of about $74 per ton HAP reduced (we estimate 1,759 tons HAP
reduced at this level). The incremental tons of HAP reduced is nearly
600 tons with the incremental cost of about $1,800 per ton HAP reduced.
    Because we estimated that the cost of achieving the 25,000 kg/yr
and 40,000 kg/yr emissions limits would be considerably greater than
what we had projected for this rulemaking at proposal, we additionally
evaluated the next less stringent emission limit that was considered
and presented in the proposal, but not selected as one of our two
proposed options for limiting emissions from the entire category--a
60,000 kg/yr MC equivalent facility-wide emission limit. For the subset
of the category that excludes the four specific industry sectors, we
estimated that the 60,000 kg/yr level reduces the MIR to between 20-in-
a million and 50-in-a million and reduces cancer incidence by about
0.19 cases/yr. These risk reductions are estimated to be achieved at
total annualized cost savings of just over $1.3 million, or a savings
of $832/ton of HAP reduced (we estimate 1,594 tons HAP reduced at this
level).
    To more fully analyze the implications of the various emission
limits, we calculated the overall and incremental annualized cost per
cancer case avoided. In this case, we compared the proposed 40,000 kg/
yr option and the next less-stringent alternative, the 60,000 kg/yr MC
equivalent emission limit. Given the overall reduction in incidence
from the baseline of 0.21 cancer cases/yr at the 40,000 kg/yr level and
the total annualized cost of $130,000, the overall cost per cancer case
avoided is about $620,000.\2\ For the 60,000 kg/yr level, there is an
estimated overall reduction in incidence of 0.19 cases/yr and a total
annualized cost savings of just over $1.3 million, resulting in an
overall savings of almost $7 million per cancer case avoided. While
these cost estimates for the overall reductions from current levels of
control appear to be modest (given the estimated cost savings of
intermediate control levels), the incremental reduction in emissions
and risk of going from the 60,000 kg/yr to the more stringent 40,000
kg/yr level are small and the corresponding cost-effectiveness
estimates of these incremental reductions are unacceptably high. The
incremental incidence avoided between the 40,000 kg/yr level and the
60,000 kg/yr level is 0.02 cases. The annualized incremental cost
between the two levels is about $1.5 million, with resulting
incremental cost per cancer case avoided of about $73 million. (Annual
operation and maintenance and annualized capital costs of $1.9 million
per year and an estimated costs savings for solvent recovery of $0.4
million per year.)
---------------------------------------------------------------------------

    \2\ For comparison purposes, we estimated that compliance with
the requirements of the National Perchloroethylene Air Emission
Standards for Dry Cleaning Facilities Final Rule (71 FR 42727, July
27, 2006), would result in an annualized cost of about $7 million to
achieve a cancer incidence reduction of 2 cancer cases per year.
This yields a cost of $3.5 million per cancer case avoided based on
the CalEPA unit risk estimate for PCE.
---------------------------------------------------------------------------

    After considering revisions to the risk and cost estimates
presented at proposal, we believe that the 60,000 kg/yr MC equivalent
emission limit for those halogenated solvent cleaning machines not
identified as being in use by one of the four sectors discussed in
Section III.A.3., above, protects public health with an ample margin of
safety and prevents adverse environmental effects. Specifically, the
60,000 kg/yr level reduces 90 percent of the HAP emissions reduced at
the 40,000 kg/yr level. The 60,000 kg/year emission limit achieves
reductions in MIR and cancer incidence that are similar to those
expected at the 25,000 kg/yr and 40,000 kg/yr emission levels. The
incremental reduction in emissions with a 40,000 kg/yr level instead of
60,000 kg/yr imposes an incremental cost of $1.5 million per year. The
incremental cost per ton of this reduction is roughly $9,000/ton.
Moreover, in comparing the 40,000 kg/yr and the 60,000 kg/yr emission
limits, the incremental cost per cancer case avoided, $73 million/case,
is substantial, supporting our conclusion that the $60,000 kg/yr
emission limit provides an ample margin of safety consistent with the
Benzene NESHAP.
3. Rationale for the Requirements for Halogenated Solvent Cleaning
Machines at Military Depot Maintenance Facilities
    For halogenated solvent cleaning machines in use at military depot
maintenance facilities, the final rule sets a facility-wide emission
limit of 100,000 kg/yr (MC equivalent emissions). In addition, the 1994
NESHAP requirements remain applicable.
    For halogenated solvent cleaning machines at these facilities that
are constructed or reconstructed after August 17, 2006, the final rule
revisions add to the previous 1994 NESHAP by requiring implementation
of the 100,000 kg/yr MC equivalent emission limit upon the effective
date of this rule or upon startup, whichever occurs later.
    We based this decision on comments received from one such facility
that we considered representative of these types of military facilities
that maintain and restore military weapons systems. They indicated an
increase in maintenance and restoration levels due to current worldwide
military activities and that they could not meet either of the proposed
emission limits within the proposed two-year compliance period. In
additional comments in response to the NODA, and in subsequent meetings
with the Agency, they indicated that they could meet the 100,000 kg/yr
emission limit within a three-year compliance timeframe. We then
projected that implementation of the 100,000 kg/yr MC equivalent
emission limit will reduce the MIR from halogenated solvent cleaning
machines associated with a military depot maintenance facility from
about six-in-a-million to about three-in-a-million with an estimated
reduction in annual cancer incidence of 0.002 cancer cases per year. An
analysis of the costs for only this facility which was based on
information from the 2002 NEI shows that the annual cost effectiveness
of complying with this limit results in a cost savings of about $625/
ton with annualized cost savings of approximately $55,761. Therefore,
we believe that a requirement for these facilities to meet a 100,000
kg/yr MC equivalent emission limit is technically feasible, provides an
annual and long-term cost savings, provides an ample margin of safety
to protect public health and prevents adverse environmental effects.
4. Rationale for Our Decisions Regarding Continuous Web Cleaners and
Halogenated Solvent Cleaning Machines at Narrow Tube Manufacturing and
Aerospace Facilities
    The requirements set forth in this final rule are not applicable to
continuous web cleaning machines, halogenated solvent cleaning machines
that are associated with the narrow tubing manufacturing industry, and
aerospace manufacturing and maintenance industry and facilities. The
requirements of the 1994 NESHAP and its subsequent amendments (where
relevant) remain applicable to all the continuous web and halogenated
solvent cleaning machines associated with the above-noted facilities.
    We received comments from these three sectors on the proposal, in
response to the NODA, and in subsequent meetings with

representatives of these industries. They submitted information that
stressed the unique nature of their cleaning operations, the technical
infeasibility, the uncertainty of our original cost estimates, the
processes involved, including review of their process changes by other
federal agencies such as FDA and FAA (see Section IV.A. for additional
discussion), and the difficulty they would experience in complying with
the proposed emission limits within the proposed timeframe. Based on
new information they provided in response to the NODA, including new
cost information, we re-analyzed the costs for each of these three
sectors and estimated the annual cost effectiveness of complying with
emission limits they provided in comments.
    For the Aerospace sector, we estimated an MIR of 30-in-a-million
and an annual cancer incidence of 0.066 at their baseline emission
level. We then projected that implementation of the 100,000 kg/yr MC
equivalent limit (the maximum reduction we discussed in the proposal)
would reduce the MIR from halogenated solvent cleaning machines
associated with this sector to about 20-in-a-million with a reduction
to their annual cancer incidence to about 0.03 cancer cases annually.
Our revised cost estimate showed a cost effectiveness of $2,000/ton
with a total annualized cost of nearly $630,000.
    For the narrow tube manufacturers, we estimated an MIR of 70-in-a-
million with an annual cancer incidence of 0.08 at their baseline level
of emissions. Based on comments from this industry indicating that they
could reasonably accomplish a 10 percent reduction in their current
emission levels within a three-year compliance time, we developed risk
and cost estimates for that level of reduction. We have estimated that
the MIR would decrease to approximately 60-in-a-million with very
little change expected in the annual cancer incidence. The annual cost
effectiveness for complying with an overall 10 percent reduction in
total emissions limit would be a cost of over $3,600/ton with total
annualized costs of nearly $700,000.
    For the continuous web cleaners, we estimated a baseline MIR risk
level of about 30-in-a-million with an annual cancer incidence of 0.03
cases. Comments from this industry suggested they could achieve an 80
percent overall control efficiency compared to their current emission
levels, within a three-year compliance period. The current NESHAP limit
requires a 70 percent overall control efficiency. To achieve the 80
percent overall efficiency, facilities would be required to reduce
emissions by 33 percent ((1-70%) - (1-80%) / (1-70%) = 33%). We
developed risk and cost estimates for that level of reduction. We have
estimated that under this scenario, the MIR would decrease to
approximately 20-in-a-million with and the annual cancer incidence
would decrease to 0.02 cases annually. The annual cost effectiveness of
complying with the 80 percent overall emission control efficiency rate
is over $3,400/ton with a total annualized costs of over $600,000.
    In summary, we are adopting no changes to the 1994 NESHAP, under
CAA Section 112(f) for the halogenated solvent cleaning machines used
by the above-noted specific industry sectors (i.e., aerospace, narrow
tube manufacturers, and the facilities that use continuous web cleaning
machines) because the current level of emissions control called for by
the existing NESHAP both reduces risk to acceptable levels and provides
an ample margin of safety to protect public health. Further, additional
standards are not necessary to prevent adverse environmental effects.
The finding regarding an ``ample margin of safety'' is based on a
consideration of the relatively small reductions in health risks likely
to result from the feasible emission reductions we evaluated, the
additional costs required to achieve further control, the lack of
technically feasible control options for these sectors, and the time
required to comply with any requirements.

C. What is the compliance schedule?

    In this final rule, in accordance with CAA section 112(i)(3), we
are promulgating a compliance deadline of three years from the
effective date of this final rule for all existing halogenated solvent
cleaning machines and for all existing halogenated solvent cleaning
machines at military depot maintenance facilities. Facilities described
in Section III.A.3 above are not subject to further requirements beyond
the 1994 NESHAP.
    At proposal, we determined that CAA section 112(i) was the
controlling provision that addresses compliance deadlines for existing
sources with regard to standards promulgated under CAA sections
112(d)(6) and 112(f)(2). See 71 FR 47684-86. We hereby incorporate our
discussion by reference. In the NODA, we asked for comments on the
issue of whether a two year compliance deadline was sufficient time to
comply with the co-proposed facility-wide emission limits. We received
significant comments on this compliance deadline issue.
    We are persuaded by the commenters representing the general
population that use halogenated solvent cleaning machines that existing
sources will need more than 2 years to comply with the final revised
standards. Affected facilities would have to plan their control
strategy, purchase and install the control device(s), and subsequently,
bring the control device(s) online. We, therefore, believe that for the
remaining halogenated solvent cleaning facilities, this final
compliance deadline of three years is more reasonable and realistic
than the proposed two year compliance deadline.

D. What is the final decision on the applicable unit risk value?

    At proposal, we explained that the Agency's IRIS health assessment
for PCE is currently being revised. Therefore, we requested comment on
the use of the CalEPA URE,\3\ the OPPTS URE,\4\ or other values in
deriving the PCE emission limit for the final rule (71 FR 47680). We
received comments both supporting and opposing our use of the CalEPA
URE for PCE.
---------------------------------------------------------------------------

    \3\ California Department of Health Services (CDHS), Health
Effects of Tetrachloroethylene (PCE), Berkeley, CA, April 1992.
(Available in the rulemaking docket.)
    \4\ U.S. Environmental Protection Agency, Cleaner Technologies
Substitutes Assessment: Professional Fabricare Processes (EPA 744-B-
98-001), June 1998. (Available at http://www.epa.gov/dfe/pubs/garment/CTSA/.
)

---------------------------------------------------------------------------

    For those situations where a particular chemical does not have a
cancer potency value in IRIS, we have established a prioritization
process for accessing other health assessment information (as described
in our ``Residual Risk Report to Congress'' on pages 56 through 58).
This hierarchy includes peer reviewed cancer potency values from EPA as
well as from other agencies that conduct chemical carcinogenicity
assessments such as the California Environmental Protection Agency
(CalEPA). See also our responses to comments on this issue in the final
Coke Oven Batteries NESHAP (70 FR 19998-20000, (April 15, 2005)). In
this final rulemaking, we have chosen to use the CalEPA URE in
preference to the OPPTS value for a number of reasons. CalEPA's PCE
cancer unit risk value was derived using two different approaches for
estimating the metabolized dose in humans, whereas the OPPTS value
incorporated a single model of metabolism. Additionally, while the
CalEPA approach allowed for the consideration of variability and
uncertainty, the OPPTS approach did not. We have used both the CalEPA
and OPPTS UREs for PCE in the risk

characterizations for the dry cleaning residual risk rulemaking (71 FR
42723) and for this rulemaking (71 FR 47670; see also the risk document
in the rulemaking docket). However, for the purposes of this
rulemaking, we have chosen to use the CalEPA URE to implement the
facility emission limits. Explicit consideration of variability and
uncertainty is more consistent with EPA's current approach for
conducting risk assessments. EPA also uses the CalEPA URE in the 1999
National-Scale Air Toxics Assessment (available at: http://www.epa.gov/ttn/atw/nata1999/
), in Superfund cleanup decisions, and in EPA's Air

Toxics Risk Assessment Reference Library (available at: http://www.epa.gov/ttn/fera/risk_atra_main.html
; dose-response values in

Appendix C at: http://www.epa.gov/ttn/fera/data/risk/vol_1/appendix_c.pdf
.

    We have the authority to revisit (and revise, if necessary) any
rulemaking if there is sufficient evidence that changes within the
affected industry or significant improvements to the science suggest
that the public might experience significantly more or less risk than
estimated in the risk assessment prepared for the rulemaking (See CAA
section 301). In particular, it may become necessary at some time in
the future to revise the facility emission limits if the pending IRIS
assessments result in significant changes to the UREs for PCE, TCE, or
MC.
    Additionally, while we have chosen to use the CalEPA URE for PCE
for implementing this rule, this should not be interpreted as a
precedent for all future rules. As was stated earlier, in the dry
cleaning residual risk rulemaking (71 FR 42723) and in this rulemaking,
we used both the CalEPA and OPPTS values to characterize the risk. When
there is uncertainty, it is EPA's preference to provide a range of
values. However, for the purposes of this rulemaking, a single value
was needed to implement the facility emission limits. EPA's choice of
the CalEPA value does not mean that this is the only value to be
considered while the EPA IRIS assessment is pending.

E. What is EPA's finding on the CAA section 112(d)(6) review
requirements?

    We stated in the proposal that in the technology review under CAA
section 112(d)(6) we did not identify any additional control
technologies beyond those that are already in widespread use within the
source category (e.g., freeboard refrigeration devices, extended
freeboards, working mode and downtime covers). We concluded that the
proposed rule changes would satisfy both CAA section 112(d)(6) and
112(f)(2). See 71 FR 47685.
    Since the August 17, 2006 proposal, we have not identified any
significant developments in practices, processes, or control
technologies. We have discovered, however, that affected industries are
researching the development of halogenated solvent cleaning machines
and alternate cleaning technologies. At some time in the future these
technologic developments could lead to significant technologies
relevant to the CAA section 112(d)(6) analysis, but we understand that
to date the engineering and implementation of such technology has not
been proven to satisfy the performance needs of the industry coupled
with the low-emission directives of the agency. We therefore conclude
that the final facility-wide emissions limits we are promulgating today
satisfy our obligations under both CAA sections 112(d)(6) and 112
(f)(2).

IV. Responses to Significant Comments

A. Significant Comments on the Proposal

    During the public comment period, EPA received significant
comments, new data, and information concerning program elements for
which we specifically sought public comments. We received favorable and
unfavorable comments on both proposed emission limits. Commenters
provided substantial information on the use of the methylene chloride
equivalency equation. We received significant comments on the
implementation of the emission limits from commenters representing
narrow tube manufacturing facilities, aerospace manufacturing and
maintenance facilities, military depot maintenance facilities,
facilities that use multiple solvent cleaning machines, and facilities
that use continuous web cleaning machines.
    All of the comments, information, and data submitted by commenters
are compiled in the Response to Comments document available in the Air
Docket ID No. EPA-HQ-OAR-2002-0009. Some of the more significant
comments are discussed below.
1. Emission Limit Option 1 or Option 2
    Comment: While four commenters supported the proposed Option 1
(40,000 kg/yr MC equivalent emission limit), other commenters
encouraged EPA to set relative standards. Another commenter, an
association of state air program administrators, believed that Option 2
(25,000 kg/yr of MC equivalent emission limit) still presented
unacceptably high risks; but noted that it was preferable to Option 1.
Three commenters supported our proposed Option 2. According to the
commenters, Option 2 would provide significant emissions reductions and
greater protection of public health, safety, and welfare. In addition
to lowering the potential cancer and non-cancer chronic health risk
associated with exposure to the three HAPs, the additional reductions
of trichloroethylene (TCE) under Option 2 would likely augment the
State's efforts to reach attainment with the 8-hour ozone standard
since TCE is identified as an ozone precursor.
    One commenter recognized the reductions in the number of people
exposed to cancer risk and the capital costs between Option 1 and the
more stringent Option 2. The commenter stated that under Option 2 the
numbers of affected sources are greater than the number of affected
sources under Option 1, but that EPA determined that those affected
sources complying with Option 2 would still save money because the
annual solvent savings were projected to exceed the annualized capital
and operating costs. The commenter added that even at a financial cost,
Option 2 would be warranted, and that given the financial savings,
Option 2 was the only reasonable choice. One commenter stated that the
proposed facility-wide emission limits would leave source owners only
two compliance options: (1) Establish internal production restrictions
or (2) install add-on capture and control equipment to ensure operating
flexibility. Another commenter requested that EPA exempt batch cold
cleaning machines operating with capture and control devices that are
subject to federally-enforceable monitoring conditions in a Title V
permit.
    Response: As stated in Section II of the Preamble, we presented and
discussed our evaluation of four other emission limits that would
reduce residual risk. These emission limits were 100,000 kg/yr, 60,000
kg/yr, 15,000 kg/yr and 6,000 kg/yr (71 FR 47680-81). In this final
rule, as stated in Section II.A. of the Preamble, we are promulgating
the 60,000 kg/yr facility-wide MC equivalent emission limit. EPA's risk
assessment for the proposal and an updated risk assessment for the
final rule using data from EPA's 2002 NEI database show that the
maximum individual risk (MIR) and population risks associated with the
majority of halogenated solvent cleaning machines would be reduced by
adopting the 60,000 kg/yr MC-equivalent emission limit. Based on the
more recent assessment using the 2002 NEI, the MIR

would be reduced from 100-in-a-million to between 20 and 50-in-a-
million and the total number of people with risks greater than 1-in-a-
million would also be reduced from 4,000,000 people to between 500,000
and 1,000,000. Our cost analyses at proposal and the more recent
revisions to the cost estimates based on the 2002 NEI show that these
emission and risk reductions are technically feasible within the three-
year time for compliance, and facilities would experience a cost
savings implementing the emission limit. Therefore, we believe that the
60,000 kg/yr facility-wide emission limit (expressed as MC equivalent
emissions) applied to the halogenated solvent cleaning machines, except
where noted, provides an ample margin of safety to protect the public's
health because it significantly reduces cancer risks, prevents adverse
environmental effects, and given the level of the risk reductions, is
technically feasible and can be accomplished at reasonable costs. EPA
is not exempting batch cold cleaning machines that operate with capture
and control devices that are subject to Title V permitting
requirements.
2. Equation for MC Equivalents
    Comment: Two commenters supported EPA's toxicity-weighted approach
for calculating the facility-wide annual emission limits for affected
sources, except where otherwise noted, that use more than one of the
three HAPs subject to the proposed Subpart T residual risk rule. This
toxicity-weighted calculation was proposed as Equations 1 and 9 in the
Preamble, and proposed 40 CFR 63.471(a)(2), respectively. In our August
17, 2006 proposal, EPA requested comment on this methodology (71 FR
47675). Another commenter was concerned about the use of the methylene
chloride equivalent. The commenter stated that the use of this term was
somewhat misleading because rather than a toxic equivalent, this
methodology reflects a weighted-emission approach using toxicity-
weighted emission rates. The commenter further stated that while EPA
conservatively added the cancer and noncancer toxicity-weighted
emissions rates, the scaling factors we used were simply the ratio of
the cancer unit-risk estimates and noncancer reference concentrations
multiplied by the post-MACT emission rate or exposure level. The
commenter also stated that because EPA did not specifically conduct
toxicological comparisons (common mode of action and metabolites and
possible synergistic interactions among the components of the mixture)
for PCE, TCE and MC, we should be careful not to use the term
``methylene chloride equivalent'' as a ``toxic equivalent,'' because
the latter is a specific term associated with a supporting body of
literature and a documented methodology. Another commenter noted that
because the current recordkeeping and annual reports requirements,
under 40 CFR 63.467 and 63.468 (f-g), were inapplicable to batch cold
cleaning machines, our proposed methodology may not be suitable for all
batch cold cleaning machines and requested flexibility in calculating
emissions so long as the alternate methodology was scientifically sound
and documented.
    Response: In this final rule, we are finalizing as proposed the use
of Equation 1 (and Equation 9) to calculate the MC equivalent for
implementing the 60,000 kg/yr emission limit or the 100,000 kg/yr
emission limit. EPA believes this methodology will facilitate the use
of an annual emissions limit for multiple HAPs and allow flexibility in
reducing the facility-wide emissions to meet this emissions limit. For
cold batch cleaning machines at area sources, the requirements in the
final rule do not apply.
3. Use of CalEPA or OPPTS URE for Implementation of the Emission Limit
    Comment: Some commenters that use large halogenated solvent
cleaning machines recommended that EPA not promulgate either Option 1
or 2 of the proposed rule, but rather defer promulgation of a final
rule until completion of the IRIS re-evaluations of the URE for PCE.
    One commenter believed that EPA included two different facility-
wide annual emission limits for PCE because the IRIS URE was not
available and will not be available before 2008. The commenter
supported the use of CalEPA URE because it was clearly more health
protective and more appropriate than the OPPTS URE value.
    One commenter stated several reasons why EPA should use the CalEPA
URE: (1) EPA's Air Toxics Risk Assessment Reference Library recommended
the use of the CalEPA URE for PCE, (2) the EPA Office of Air Quality
Planning and Standards (OAQPS) recommended the use of the CalEPA URE in
situations in which there are no IRIS data available (see EPA's
``Prioritization of Data Sources for Chronic Exposure'' Web site), and
(3) OAQPS used the CalEPA URE for PCE when conducting the 1999 risk
assessment for the National-Scale Air Toxics Assessment. They believed
that EPA has an established precedent for use of the CalEPA URE and
recommended that it be used for this residual risk standard as well.
    Three commenters, one identifying itself as operating two
continuous web cleaning lines in the world's largest integrated
production of aluminum and aluminum semi-fabricated products stated
that the two PCE UREs differ by a factor of ten and that EPA's
selection of the applicable URE would obviously have a significant
impact on control options available to their facility. They expressed
concern that EPA would finalize an emissions limit by selecting an
inappropriate URE and prior to completion of the IRIS reassessment for
PCE. According to the commenter, the fact that the final IRIS URE ``may
be different from both the CalEPA and OPPTS values'', means that
inappropriate or unnecessary emission reduction strategies could be
required as a result of EPA's promulgating the wrong PCE facility-wide
limit in a final rule.
    Another commenter suggested that EPA delay promulgation of this
final rule until completion of IRIS assessments for PCE and TCE. One
commenter stated that while EPA referenced both the OPPTS and the
CalEPA UREs, there was little or no mention made of other URE studies
conducted for PCE which would potentially indicate a different URE. The
commenter stated the same is believed to be true regarding the URE for
TCE.
    Response: EPA has explained that when a particular chemical does
not have a cancer potency value in IRIS, we have established a
prioritization process for assessing other health assessment
information (as described in our ``Residual Risk Report to Congress''
on pages 56 through 58). This hierarchy includes peer reviewed cancer
potency values from EPA as well as from other agencies that conduct
chemical carcinogenicity assessments such as CalEPA. See also our
response to comments on this issue in the final Coke Oven Batteries
NESHAP (70 FR 19998-20000, (April 15, 2005)).
    Because we have not yet issued a final IRIS health assessment for
PCE, we are using the CalEPA unit risk estimate (URE) of 5.9 X
10-6 (ug/m3)-1 to implement the
emission limit for PCE in this final rule. See section III.D. of this
Preamble for further discussion of our decision to use the CalEPA
cancer URE.
    We also have the authority to revisit (and revise, if necessary)
any rulemaking if sufficient evidence becomes available that changes
within the affected industry or significant improvements to the
underlying science suggest that the public is exposed to significantly
more or less risk than

estimated in the risk assessment prepared for this rulemaking (See CAA
section 301). See also Ethylene Oxide Emissions Standards for
Sterilization Facilities Residual Risk Rules (71 FR 17712, 17715,
(April 7, 2006). In particular, it may become necessary at some time in
the future to revise the facility emission limits if the pending IRIS
assessments result in significant changes to the UREs for PCE, TCE, or
MC.
    Additionally, while we have chosen to use the CalEPA URE for PCE
for implementing this rule, this should not be interpreted as a
precedent for all future rules. As was stated earlier, in the dry
cleaning residual risk rulemaking (71 FR 42723) and in this rulemaking,
we used both the CalEPA and OPPTS values to characterize the risk. When
there is uncertainty, it is EPA's preference to provide a range of
values. However, for the purposes of this rulemaking, a single value
was needed to implement the facility emission limits. EPA's choice of
the CalEPA value does not mean that this is the only value to be
considered while the EPA IRIS assessment is pending.
4. Compliance Deadline
    Comment: The majority of facilities that use halogenated solvent
cleaning machines suggested that EPA should allow at least three years
for existing sources to comply with the new requirements. Two
commenters contended that EPA should be consistent with the HON rule
\5\ and provide affected facilities three years after the effective
date of the promulgated standard to comply. Another commenter stated
that the narrow tubing manufacturers could not comply with the proposed
compliance period because compliance would require between one and two
years to evaluate non-regulated solvents and an additional two to three
years to obtain FDA and air permit approvals and implement the
necessary equipment modifications. All commenters stated that sources
subject to this new rule would need time to evaluate their compliance
options; conduct feasibility testing (for solvent substitution) to
ensure they can still achieve customer specifications; and design,
build, and/or install any equipment or facility modifications
potentially required. They stated that our proposed two year compliance
deadline would be insufficient time for the regulated sources to
comply. Two commenters stated that the proposed two year compliance
time frame was not sufficient time for the installation of vacuum-to-
vacuum machines. The commenters stated that even if the technology
existed, that in order to meet the proposed two year compliance
deadline, they would be required to take the following measures: (1)
Conduct initial research and development effort to determine a control
strategy; (2) perform a pilot study using the selected control
strategy; (3) demonstrate to their customers that the resulting product
meets contract specifications; (4) get acceptance by their customers
that the change meets contract specifications; (5) design engineering
work to develop the selected equipment and apply for air pollution
control and other permits; (6) obtain permits to install the selected
equipment; (7) order the equipment; (8) fabricate the equipment; (9)
prepare the shop floor for installation of equipment; (10) receive and
install the equipment; and (11) place the equipment in operation.
---------------------------------------------------------------------------

    \5\ National Emission Standards for Organic Hazardous Air
Pollutants from the Synthetic Organic Chemical Manufacturing
Industry, (71 FR 76603) (December 21, 2006)).
---------------------------------------------------------------------------

    Three other commenters believed that the proposed two years
compliance schedule did not provide sufficient time for the affected
facilities to fully assess the impacts and develop approved
alternatives. The commenters requested an extension of the compliance
period. They stated that EPA has authority to allow up to three years
for affected facilities to comply and that permitting authorities have
authority to grant an additional one year for compliance purposes,
under CAA section 112(i).
    A large military depot maintenance facility commented that the
proposed compliance time allowed in the proposed rule was inadequate.
They also agreed with the Preamble discussions as to whether EPA could
allow up to three years for existing sources to comply with the
proposed limits. The commenter recommended that EPA allow a three-year
compliance deadline.
    Two commenters supported EPA's proposed two-year compliance
deadline. One of the commenters, however, pointed out that existing
solvent cleaning machines could receive a one year extension of time
from permitting authorities. The commenter believed that the
Congressional intent behind the compliance deadlines in CAA section
112(f) was to insure an expedited compliance schedule (90 days with a
possible two-year extension) for controlling emissions from facilities
that result in unacceptable risk levels. Two States provided comments
supporting the proposed two year compliance deadline and one commenter
advocated a 90-day compliance period.
    Response: In this final rule, in accordance with CAA section
112(i)(3), EPA is promulgating a three-year compliance deadline from
the effective date of this rule for all the existing affected sources.
As explained in Section III.C. of the Preamble, we believe that CAA
section 112(i) is the controlling provision addressing compliance
deadlines for existing sources with regard to standards promulgated
under CAA sections 112(d)(6) and (f)(2). EPA believes this will give
owners or operators of solvent cleaning machines the necessary time to
evaluate technologies for controlling emissions and possible
alternatives to halogenated HAP solvent cleaning.
    Comment: One commenter stated that proposed Sec.  63.460(i) would
allow sources that only have existing halogenated solvent cleaning
machines two years to comply, but if they construct or reconstruct a
single machine after August 17, 2006, they would lose the two-year
compliance period. The commenter recommended that any facility that has
existing halogenated solvent cleaning machines and that exceeds the
proposed facility wide emission limits should be allowed two years from
the date of the final rule to comply with the standard, even if one or
more halogenated solvent cleaning machines are constructed or
reconstructed after August 17, 2006.
    Another commenter stated that if the Agency finalized the proposed
rule, the compliance schedule should be amended to (1) Require new
facilities constructed after the date of promulgation to be in
compliance upon startup; (2) consider new facilities constructed prior
to the date of promulgation to be existing facilities; (3) allow
existing degreasing facilities that installed new equipment after the
date of proposal, but prior to the date of promulgation, ten years to
come into compliance with any new requirements consistent with CAA
section 112(i)(7), and (4) allow the maximum amount of time possible
for existing Halogenated Solvent Cleaning facilities to come into
compliance. This commenter alluded to a three-year timeframe. The
commenter cited one example of where the installation of new equipment
at an existing facility would require additional or redesigned floor
space and thus would require additional time for compliance.
    Response: As stated in the earlier response, and in Section III.C.
of this Preamble, we believe that it is reasonable to conclude that CAA
section 112(i) is the controlling provision

addressing compliance deadlines for existing sources with regard to
standards promulgated under CAA section 112(d)(6) and 112(f)(2). Thus,
in this final rule, in accordance with CAA section 112(i)(3), EPA is
promulgating a three-year compliance deadline from the effective date
of this rule for existing sources. Further, for purposes of today's
rule, existing sources are affected facilities (as defined in Sec.
63.461) on which construction or reconstruction began on or before
August 17, 2006. New sources are affected facilities that commence
construction or reconstruction after August 17, 2006. This is
consistent with CAA Section 112(i)(1)-(3). Additionally,
``construction'' and ``reconstruction,'' are defined at 40 CFR 63.2.
However, changes to the emission controls at a facility made to comply
with existing source standards in today's rule do not trigger the
reconstruction threshold.
5. Applicability of Control Requirements
    Comment: One commenter that uses continuous web cleaning machines
stated that it had installed two carbon adsorption devices (CAD) to
address the TCE reductions required by the 1994 NESHAP. According to
the commenter, even an upgrade of the systems would likely not enable
the facilities to achieve either proposed emissions limit. The
commenter suggested that for facilities that use continuous web
cleaning machines, EPA should evaluate a range of emission reduction
limits. The commenter stated that this method would have been
consistent with the alternative standards set for the continuous web
cleaning machines by the 1994 NESHAP.
    Response: In light of this and similar comments by the aerospace
and narrow tubing industries, EPA issued a NODA to gather specific data
on the technical feasibility and costs of complying with the proposed
emission limits, if feasible, and the period of time required to comply
with the proposed emissions limit (71 FR 75184, (December 14, 2006)).
EPA has re-evaluated the technical feasibility, costs and other factors
that relate to facilities operating continuous web cleaning machines.
Consequently, in this final rule, we are not promulgating any facility-
wide emission limits for facilities that operate continuous web
cleaning machines, facilities that operate halogenated solvent cleaning
machines for the aerospace manufacturing and maintenance industry, and
the narrow tubing manufacturing industry.
    Comment: Numerous commenters from both the narrow tubing
manufacturing industry that use MC, PCE and TCE, and airline
maintenance facilities and aerospace industry that use PCE stated that
switching to TCE or MC would be an unsuitable compliance option. They
stated that facilities have procedural requirements for the higher
vapor temperature of PCE and that TCE and MC's vapor temperature is
inadequate for proper cleaning. The commenters stated that many
original equipment manufacturers have not approved the use of
alternative degreasing solvents. The commenters also stated that
changing solvents involved a rigorous approval process by the original
equipment manufacturers and the Federal Aviation Administration (FAA)
in order to ensure that safety and quality criteria are met. The
commenters stated that such an approval process could take more than
two years.
    The commenter also stated that EPA's proposed retrofit options for
freeboard ratios, working mode covers and freeboard refrigeration
devices are not expected to be sufficient to enable the facility to
comply with the proposed facility-wide emission limits of the proposed
rule. The commenter also stated that there are few manufacturers of
vacuum-to-vacuum degreasing machines and they were not aware of this
technology effectively cleaning parts of specific types and sizes.
According to the commenter, similar facilities that installed the
technology incurred costs of over $1 million with new annualized costs
of approximately $80,000 per year. The commenter was concerned that
compliance with the proposed standards would be achieved by using
expensive technology, that has high capital costs and operating costs
and that may not be proven effective or reliable for the operations of
subject facilities.
    Response: In response to this comment and certain comments
discussed below, EPA issued a NODA (71 FR 75184, (December 14, 2006))
to gather more information pertinent to the halogenated solvent
machines used by the aerospace industry, narrow tubing manufacturing
industry, and the facilities that use continuous web cleaning machines.
Responses to the NODA provided significant data and information that
have led EPA to determine that it is both technologically infeasible
and not cost effective for these industries to implement any further
emission controls or requirements. Consequently, as stated in Section
III.A.3., of the Preamble, we are not promulgating any facility-wide
emission limits for halogenated solvent cleaning machines used by the
aerospace manufacturing and maintenance industry, the narrow tubing
manufacturing industry and for continuous web cleaning machines.
    Comment: Two commenters associated with the aerospace industry
stated that the FAA, Food and Drug Administration (FDA) and the Nuclear
Regulatory Commission (NRC) guidelines for safety and quality control
often dictate the types of solvents and materials that may be used in
aerospace operations. According to the commenters, solvent cleaning
criteria determined the quality of adhesion between aircraft assemblies
and components and the various coatings, primers, sealants, and
adhesives later applied to their surfaces, and improper degreasing
could cause loss of coating adhesion and ultimate failure of specific
aircraft component parts. The commenters also stated that they had
explored solvent alternatives such as aqueous cleaners, and had
encountered incompatibilities with FAA guidelines, such as inability to
meet the degree of cleaning required, incompatibility of the parts
being cleaned with the cleaning solution, longer required cleaning
time, and problems associated with moisture left on parts being
cleaned. The commenter stated that these regulatory and product
specifications frequently dictated or otherwise limited aerospace
cleaning options to PCE or TCE. However, some aerospace facilities
maintain their PCE cleaning capacity because certain, very specific
aerospace parts cannot be processed with MC or alternative solvents.
    Response: In response to this comment, as earlier explained, EPA
issued a NODA (71 FR 75184, (December 14, 2006)) to gather more
information pertinent to the halogenated solvents cleaning machines
used by the aerospace industry, narrow tubing manufacturing industry,
and the facilities that use continuous web cleaning machines. Responses
to the NODA provided significant information that has led EPA to
conclude that it is both technologically infeasible and not cost
effective for the above-noted facilities to implement any further
emission controls or requirements. (See Section III.A.3. of the
Preamble on costs of compliance). EPA is also persuaded that some
halogenated solvent cleaning processes for the aerospace and narrow
tubing industry are controlled by FAA, FDA, the NRC guidelines, and
from protocols of original equipment manufacturers. Therefore, EPA is
concluding in this final rule that solvent switching from PCE or TCE to
MC may not be a viable option in some instances for the aerospace
industry.

Consequently, as stated earlier in Section III.A.3., of this Preamble,
EPA is not promulgating facility-wide emission limits for halogenated
solvent machines used by the aerospace manufacturing and maintenance
industry, the narrow tubing manufacturing industry and for continuous
web cleaning machines.
    Comment: Commenters from the narrow tube manufacturing industry
stated that they use ``one of a kind'' machines in their degreasing
operations. They described these machines as very large, some with
dimensions approaching 110 ft. long by 10 ft. deep and 42 inches wide,
with a capacity of 7,000 gallons of solvent. According to the
commenters, these machines also heat the solvent, usually TCE, to its
boiling point while condenser coils prevent evaporation by forming a
cold air blanket over the cleaning machine in order to limit emissions.
In addition, they explained that these machines are covered when not in
use.
    They also stated that the installation of vacuum-to-vacuum cleaning
machines is not a feasible option because of their products' sizes and
the lack of engineering information to establish whether machines of
such size can be engineered and produced. They stated that EPA's
proposed requirements would require them to design, obtain permits,
develop and install these systems within two years.
    Response: In response to this comment, as earlier explained, we
issued a NODA (71 FR 75184, (December 14, 2006)) to gather more
information pertinent to the halogenated solvent cleaning machines used
by the aerospace industry, narrow tubing manufacturing industry, and
the facilities using continuous web cleaning machines. Responses to the
NODA provided significant information that has led EPA to determine
that it is both technologically infeasible and not cost effective for
the above-noted facilities to implement any further emission controls
or requirements. EPA is also persuaded that it may be quite difficult
for the above-noted industries to reduce emissions through chemical or
physical means and technology applications to the levels required by
our final promulgated emissions limits. Accordingly, due to the costs
associated with compliance, technical feasibility, and other factors,
EPA has determined that the current MACT requirements provided for the
narrow tubing manufacturing industry both reduce HAP emissions to
levels that both pose acceptable risk and protect public health with an
ample margin of safety. As stated earlier in Section III.A.3., of the
Preamble, EPA is not promulgating facility-wide emission limits for
halogenated solvent cleaning machines used by the narrow tubing
industries.
    Comment: Two commenters stated that switching from PCE and/or TCE
to MC (indicated as being lower risk) as a compliance alternative under
the proposed revisions would likely result in an increased danger to
public health and, more specifically, potentially increase the danger
from employee exposure to MC emissions. The commenter stated that
because employee exposure to MC is specifically regulated by the
Occupational Safety and Health Administration (OSHA), switching to MC
would be an error. According to the commenter, this is because
applicable OSHA regulations would limit and/or restrict MC and would
lead to increased employer costs, a fact the commenter believed EPA did
not consider. One commenter stated that some halogenated solvent
cleaning machines may have the potential for undetected fugitive
emissions. The commenter added that the necessary monitoring for
adequate employee protection from overexposure to MC would be far more
expensive, more extensive, and more difficult to implement than
monitoring for TCE.
    Response: Before proposal, EPA was aware of the requirements of the
Occupational Health and Safety Administration concerning worker safety
when MC is used. 29 CFR part 1910, which are the applicable OSHA
regulations, require employers to make an initial determination of each
employee's exposure to MC. If the employer determines that employees
are exposed below the action level, employers are required to make a
record of the determination. Conversely, if the employees are exposed
to MC above the action levels, employers are required to perform
exposure monitoring.
    In addition, EPA did not consider any costs associated with MC
monitoring at proposal. EPA believes, however, that a facility would
not incur costs if MC emissions do not exceed the OSHA levels. If a
facility experiences worker exposure of MC emissions over the OSHA
level, the facility incurs costs to develop a control plan for fugitive
emissions and possibly implement an employee medical monitoring plan.
To account for the possibility of increased costs, we reduced the
number of units assumed to use solvent switching.
6. Costs Associated With Compliance
    Comment: Seven commenters, from the aerospace and narrow tube
manufacturing sectors, stated that EPA had underestimated its cost
basis for vacuum-to-vacuum technology in the proposed rule. One
commenter stated that because EPA's estimation used the costs for small
halogenated solvent cleaning machines and applied the credit for cost
reduction from recovered solvent to the large halogenated solvent
cleaning machines with large amounts of recovered solvent, the estimate
erroneously yielded a false return on investment. The commenter stated
that discussions with manufacturers of available vacuum-to-vacuum units
suggested costs approximately five times higher than the assumptions
used by EPA for each unit, and this was assuming that the manufacturers
could develop scaled-up units suitable for narrow tubing manufacturers.
The commenter stated that because the larger size of their products
would require construction of the new unit while maintaining operation,
facilities would need to undergo building expansion. The commenter
anticipated that installation costs, including building and required
utilities and infrastructure, would likely be approximately three times
the equipment cost. According to the commenter, assuming the technology
was successful, EPA's capital cost basis was approximately fifteen
times below its likely cost range. The commenter further stated that
EPA's assumption of 97 percent solvent recovery was unlikely with
regard to hypothetical future large units that would require storage
and movement of solvent between storage tanks, solvent cleaning
machines and other ancillary equipment. The commenter concluded that
EPA's assumptions of the project payback were unrealistic both for
large operations, whose capital cost was underestimated, and for small
operations, whose solvent recovery payback would be smaller than the
average figures used in the analysis.
    Response: In response to this comment, as explained earlier, EPA
issued a NODA (71 FR 75184, (December 14, 2006)) to gather more
information on the costs of complying with the proposed standards by
the aerospace industry, narrow tubing manufacturing industry, and the
facilities that use continuous web cleaning machines. Responses to the
NODA provided significant information that has led EPA to determine
that it is both technologically infeasible and not cost effective for
the above-noted facilities to implement any further emission controls
or requirements.
    As earlier stated, EPA is also persuaded that some solvent cleaning
processes for the aerospace and narrow tubing industry are controlled
by protocols from the FAA, FDA, NRC and

from protocols to satisfy original equipment manufacturers'
specifications. As earlier stated, EPA has also concluded in this final
rule that solvent switching from PCE or TCE to MC may not be a viable
option in some instances for the aerospace industry. As also explained
earlier in Section III.B. of the Preamble, EPA has re-analyzed the cost
assumptions made at proposal for the aerospace industry separate from
the halogenated solvent cleaning machines that are covered by this
final rule, and has determined that due to costs, technical
feasibility, and other factors requiring additional controls, would not
be feasible at this time. Consequently, as stated earlier in section
III.A.3 of the Preamble, we are not promulgating facility-wide emission
limits for halogenated solvent cleaning machines used by the narrow
tubing and aerospace manufacturing and maintenance industries.
    Comment: Commenters that use continuous web cleaning machines
stated that EPA's analysis of the technology and cost impacts of the
two proposed emission limits failed to consider the impacts on
continuous web machines. The commenters stated that while EPA
identified numerous compliance options, solvent switching from PCE to
TCE or MC would be the sole compliance option for continuous web
cleaning machines. The commenters further stated that EPA was correct
to conclude that neither retrofits nor machine replacement would be an
available compliance option for continuous web cleaners; however, the
commenters stated that ``EPA should not have concluded that solvent
switching would be an available option for continuous web cleaners.''
The commenters further stated that switching from TCE to MC is not an
available option because ``MC reacts with chemically active metals such
as aluminum.'' The commenters also stated that MC is incompatible with
some of the gaskets and seals in pumps, ports and manifold systems. The
commenters added that MC is less stable as a continuous web cleaning
solvent and would require additional monitoring and probably additional
stabilization control systems. Additionally, the commenters stated that
MC is not readily adsorbed by the carbon in carbon adsorption devices
and, as such, solvent switching would require reconfiguration and
possibly rebuilding of the carbon adsorption devices. According to the
commenters, MC requires longer dwell time in the carbon beds, which
would in turn require a greater carbon surface area and larger carbon
filtration systems. The commenters also stated that quantities of TCE
would react with MC and that facilities would need to conduct a
complete purging of systems in order to prevent cross contamination.
The commenters further stated that such purging would include the
removal of significant production line components, which would lead to
increased compliance costs.
    The commenters also stated that EPA estimated a 29 percent increase
in solvent consumption if switching from TCE to MC. The commenters,
however, expected much higher increases. The commenters explained that
because steel that is placed in cleaning machines is slightly heated
above ambient temperature, any slight temperature elevation would cause
MC to vaporize more readily than TCE. The commenters claimed that
increases in solvent consumption rate would ultimately create elevated
vapor concentrations in the carbon adsorption device thereby making
recovery more difficult. The commenters further claimed that even
though MC is cheaper per unit volume, more MC would be required to
achieve the same level of cleaning.
    The commenters also maintained that add-on control equipment,
retrofits and machine replacement technologies identified in the
proposed rule are for the typical halogenated solvent cleaning machines
that were subject to the 1994 NESHAP, and not continuous web cleaning
machines or systems. The commenters stated that modifications such as
modifying freeboard ratios, adding working mode covers, or retrofitting
freeboard refrigeration devices are inapplicable because no freeboard
exists in continuous web cleaning machines, which are enclosed, with
the exception of entrance and exit points during normal operations. The
commenters further stated that vacuum-to-vacuum machines are only
appropriate for batch cleaners. Because of these technical issues, the
commenters stated that EPA did not evaluate the costs and technological
feasibility of the facility-wide emission limits for the continuous web
cleaning machines.
    Response: In response to this comment, as stated earlier, EPA
issued a NODA (71 FR 75184, (December 14, 2006)) to gather more
information on the costs of complying with the proposed standards by
the aerospace industry, narrow tubing manufacturing industry, and the
facilities using continuous web cleaning machines. As also stated
earlier, responses to the NODA-provided significant information has led
EPA to re-evaluate costs of installing CADs and vacuum-to-vacuum
machines. EPA has determined that compliance by continuous web cleaning
machines with either the proposed 40,000 kg/yr limit or the 60,000 kg/
yr MC equivalent limit would not be cost effective and either limit may
be technically infeasible in some instances. Consequently, as stated in
Section III.A.3 of this Preamble, EPA is not requiring continuous web
cleaning machines to comply with the facility-wide emission limits we
are promulgating for this final rule. EPA is concluding that the
current level of control by the existing NESHAP both reduces HAP
emissions to levels that present an acceptable risk and provides an
ample margin of safety to protect public health and prevent adverse
environmental effects.
    Comment: One commenter, an industry association representing
producers and users of halogenated solvents, indicated that MC is not
compatible with some substrates because of its aggressive nature. In
addition, the commenter stated that MC's low boiling point shortens the
effective cleaning time and makes it ineffective for light-gauge metals
where incomplete rinsing action may cause staining. According to the
commenter, the low boiling point of MC also makes it less effective on
stubborn soils, including high-melting point waxes and pitches and
grossly contaminated parts. The commenter stated that PCE's higher
boiling point makes it ideal for these applications. According to the
commenter, PCE is also a popular choice for closed-loop equipment,
where PCE's inherent stability reduces the possibility of hydrolysis.
    The commenter also stated that while MC has the lowest vapor loss
rate from an idling halogenated solvent cleaning machine, its low vapor
density makes it the most difficult to control in a working degreaser
where air movements generally increase losses. The commenter also
stated that MC has the lowest vapor recovery rates in carbon adsorption
systems used to collect solvents from many web and in-line machines. In
addition, the commenter stated that MC users are subject to a
comprehensive OSHA standard that requires a medical surveillance and
removal program not required for PCE and TCE users.
    Response: EPA recognizes that there are chemical and physical
limitations when considering solvent switching as a method to reduce
emissions in compliance with both the proposed and final facility-wide
emission limits we are promulgating in this final rule. In the proposed
rule, EPA assumed 30

percent of facilities would switch to a less potent solvent; however,
significant comments have led us to re-evaluate these assumptions.
Consequently, with regard to our solvent switching analysis, for this
final rule, EPA has reduced the number of units for which solvent
switching is an option from 30 percent to 15 percent. The cost analysis
in Section III.B. of the Preamble to this final rule reflects this
change.
7. General Comments
    Comment: A number of commenters stated that the 1999 NEI data did
not reflect current emission levels and were not a sufficient basis for
assessing technical or economic feasibility. Some believed that the
1999 NEI database was obsolete and provided an incomplete emission
database when used as a primary source of data for halogenated solvent
emissions. The commenter stated that the industry had changed since
1999 due to local, regional, and State regulatory pressures. The
commenter indicated that the most significant change since 1999 was the
phase out of TCA manufacture for emissive use, which effectively
eliminated its use for solvent cleaning. The commenters pointed out
that EPA had access to the 2002 NEI database and encouraged EPA to re-
evaluate the risk assessment using the updated database.
    Response: In response to public comments we received on the August
17, 2006 rule proposal, we reassessed the risks associated with the
halogenated solvent source category using the 2002 NEI inventory. The
proposal was based on the 1999 inventory. These data were not available
at the time the proposal was being developed.
    Comment: One commenter stated that EPA established a MACT standard
for the continuous web subcategory in December 1999 and therefore,
Section 112(f) risk analysis for the subcategory is not required until
December 2007. The commenter stated that the continuous web subcategory
was established five years after the standard for the other halogenated
solvent machines. According to the commenter EPA's proposed rule fails
to recognize that under this requirement EPA has eight years from
December 3, 1999 (or by December 3, 2007) to conduct the residual risk
evaluation for the continuous web subcategory.
    Response: Section 112(f)(2)(A) requires the Administrator to
promulgate applicable standards ``within 8 years after promulgation of
standards,'' under section 112(d). We read this provision as allowing
for our promulgation of standards, under section 112(f), within 8 years
of the effective date of section 112(d) requirements, rather than
within 8 years of the compliance date of the section 112(d)
requirements. (See for example, section 112(f)(3) (``the Administrator
shall establish a compliance date or dates * * * which shall provide
for compliance as expeditiously as practicable but in no event later
than three years after the effective date of such standard.'' (Emphasis
added)). The effective date of the Halogenated Solvent Cleaning NESHAP
is December 2, 1994, and not December 3, 1999, as suggested by the
commenter, although we subsequently made certain clarifications and
amendments to these requirements. Our obligation to promulgate residual
risk standards for this source category is therefore past, and we are
now operating under a consent decree that required our promulgation of
today's rule on or before December 15, 2006, subsequently extended to
April 16, 2007. We also believe that there is nothing in the Act that
precludes our completion of the residual risk review prior to 8 years
after promulgation of section 112(d) standards.
    Comment: One commenter stated that EPA had used a very simplistic
model to perform the emissions evaluations which may be acceptable for
an initial screening, but that the Agency had failed to provide
information to either validate its approach or any indication as to
whether the presented risk levels exceed the upper bound limit of 100-
in-a-million using the correct facility information such as stack
parameters. The commenter requested that EPA review the seven
facilities with an estimated cancer risk greater than 100-in-a-million
to determine whether the use of average stack parameters was
appropriate and to revise the proposed rule accordingly. The commenter
also requested that EPA add an option allowing facilities to conduct
site-specific emission modeling to determine if a facility meets or
exceeds the allowable MIR, which would depend on which option EPA
finalized. Subsequently, EPA could use this modeling to set a site-
specific facility limit that is higher than either proposed options.
    Response: The choice of the proposed emission limits and the final
emission limit is based on the level of risk reduced, cost and
technical feasibility to achieve a particular emission limit. While we
acknowledge the uncertainty inherent in the NEI data used, its effect
on risk is not the only consideration for the proposed emission limits.
In spite of the fact that perhaps 50 percent of the release parameters
in the 1999 NEI database may be defaults, our understanding of this
source category and our best engineering judgment suggested the data
were reasonable to use in our risk assessment, (e.g., the range of
stack heights was appropriate for these sources). We also acknowledged
that while our risk assessment was likely to overestimate risks, this
overestimate was not likely to be large because of the many variables
and assumptions used in the assessment that would yield lower estimated
risk levels, (e.g., the use of a probabilistic method for evaluating
population risks). Therefore, a focused evaluation of the release
parameters of a few facilities at the upper end of the risk spectrum,
while possibly having some effect on their individual risk levels, is
not likely to affect our overall conclusions about the level of risk
from the entire source category.
    Concerning the site specific emission modeling, EPA did not
incorporate in the proposed rule an approach that would allow site
specific modeling. Instead, EPA assessed risk on a source category
basis. EPA also did not incorporate in the proposed rule an approach a
low-risk alternative for compliance.

V. Responses to Significant Comments on EPA's December 14, 2006, Notice
of Data Availability (NODA)

A. Emission Limits

    Comment: Two commenters from the aerospace industry submitted
available compliance options for the 40,000 kg/yr MC equivalent
emission limit. One option involved switching from HAP chlorinated
solvents to n-propyl bromide. Another option involved the facilities
switching to an alkaline degreasing system with ultrasonic wash tanks.
    One aerospace facility, which had a large operation with multiple
halogenated solvent cleaning machines, submitted very detailed
descriptions of each machine, the options available and the associated
costs of implementation. For their multiple machines, they presented
twelve emissions reduction options, five of which reduced their
emissions to below the 40,000 kg/yr MC equivalent limit. The compliance
options include a combination of machine covers, extension areas,
additional drain time for parts, installing larger or additional carbon
absorption systems and switching some current machines with vacuum-to-
vacuum machines. The commenter indicated that completing these

compliance options would take six years or more.
    Response: EPA recognizes that a few small aerospace facilities may
operate with emissions at or below both the proposed and final
promulgated emission limits. In the proposal, EPA assumed solvent
switching and other technologies could be applied at a reasonable cost.
EPA has discovered, however, that this industry is bound to the use of
chlorinated solvents and solvent switching is not a viable option for
compliance. As earlier stated, EPA also recognized that the affected
facilities cannot undertake all the necessary modifications within the
three-year compliance period. EPA also notes that all these
considerations are true for the final promulgated 60,000 kg/yr emission
limit.
    Comment: Two commenters that use continuous web cleaning machines
maintained that they could not comply with either of the proposed
emission limits. Both facilities stated that they had installed carbon
absorption devices, which operated at about 99 percent control
efficiency, but that most of their emissions could not be captured by
these devices because of the nature of continuous web cleaning
machines. According to the commenters, fugitive emissions occur in
different locations along production lines and along the cleaning
process. The commenters provided some possible additions to their
cleaning systems that would achieve additional reductions, but they did
not provide information on the emission levels they could attain. The
commenters stated that there are limited available technologies to
capture emissions and that it would be technically difficult for them
to capture a significant portion of their emissions. The commenters
also maintained that attaining a degree of control rather than meeting
an emission limit is a more appropriate measure of their emission
reduction capability.
    Response: EPA recognizes that continuous web machines are designed
differently from general halogenated solvent cleaning machines, i.e.,
batch and in-line cleaning machines. As explained in earlier responses,
we have determined that it is both technologically infeasible and not
cost effective for continuous web cleaning machines to comply with our
final promulgated emissions limit. As also stated in Section III.A.3.
of the preamble, in this final rule, we are not setting any emissions
limits for facilities that use continuous web cleaners. As also
explained earlier, we are concluding that the current level of control
for continuous web cleaning machines called for by the existing NESHAP
reduces HAP emissions to levels that present an acceptable risk,
protects public health with an ample margin of safety, and prevents
adverse environmental effects.
    Comment: We received significant comments from five narrow tubing
manufacturers. These commenters presented very significant and
compelling reasons as to why they could not meet the proposed emission
limits. The commenters indicated that carbon absorption systems were
the only available feasible control technology but that installation
would result in only a maximum of 25 percent overall emissions
reduction. The commenters stated that vacuum-to-vacuum machines have
not been engineered or tested to the sizes that are required for their
specific industrial processes. They claimed that such large vacuum-to-
vacuum machines are not available from machine manufacturers. One
commenter stated that after five years of research and design they may
be able to achieve the 100,000 kg/yr MC equivalent emission limit.
    Response: EPA is persuaded that narrow tube manufacturing
facilities are the most technically challenged in reducing emissions to
the levels called for by either our proposed or final promulgated
60,000 kg/yr emission limit. EPA has also determined that this industry
is bound to the use of chlorinated solvents and solvent switching is
not a viable option for compliance. Furthermore, EPA is persuaded that
vacuum-to-vacuum technology has not developed to a point where this
industry can install these machines into their processes with certainty
of performance. Therefore, EPA has concluded in this rule that this
industry could only achieve both the proposed and final promulgated
emissions limits by implementing newly engineered and untested
technology. Consequently, as explained earlier in Section III.A.3. of
the Preamble, EPA is adopting no changes to the 1994 NESHAP for the
halogenated solvent cleaning machines used by the narrow tubing
industry, and we are concluding that the current level of control by
the existing NESHAP reduces HAP emissions to levels that present an
acceptable risk, protects public health with an ample margin of safety,
and prevents adverse environmental effects.

B. Cost Impacts

    Comment: One aerospace facility maintained that the application of
various technologies would result in 85 percent overall emissions
reduction at capital costs of between $1.1 and $1.7 million, for this
particular facility, but that it would need considerable more time
beyond the proposed two years compliance period to implement the
proposed emissions limits.
    Response: As a result of the comments on compliance costs, EPA re-
evaluated the ability of the aerospace industry to feasibly implement
in a cost effective manner other emission limits we discussed at
proposal but did not propose (ranging from 60,000 kg/yr to 250,000 kg/
yr MC equivalent emission limits). We relied on commenters' submissions
to assist us in revising our cost estimates for complying with these
emissions limits by the aerospace industry and also relied on it in
part in applying cost assumptions to the remainder of the other
industries that use halogenated solvent cleaning machines.
    The results indicated that implementing additional emission control
levels, (ranging from 60,000 kg/yr to 250,000 kg/yr MC equivalent
emission limits), within a three-year compliance period would result in
total capital costs of over $9 million with a cost effectiveness of
about $2,000/ton of solvent used. Furthermore, EPA calculated the total
annualized costs for each cancer case avoided would be more than $17.5
million for the 100,000 kg/yr MC equivalent emission limit. Therefore,
EPA is concluding in this final rule that the NESHAP requirements for
aerospace manufacturing and maintenance degreasing machines, provide an