[Federal Register: August 17, 2006 (Volume 71, Number 159)]
[Proposed Rules]
[Page 47669-47690]
[DOCID:fr17au06-14]

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Part V

Environmental Protection Agency

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40 CFR Part 63

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

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 63

[EPA-HQ-OAR-2002-0009, FRL-8210-3]
RIN 2060-AK22

National Emission Standards for Hazardous Air Pollutants:
Halogenated Solvent Cleaning

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The EPA is proposing revised standards to limit emissions of
methylene chloride (MC), perchloroethylene (PCE), and trichloroethylene
(TCE) from existing and new halogenated solvent cleaning machines. In
1994, EPA promulgated technology-based emission standards to control
emissions of methylene chloride (MC), perchloroethylene (PCE),
trichloroethylene (TCE), 1,1,1,-trichloroethane (TCA), carbon
tetrachloride (CT), and chloroform from halogenated solvent cleaning
machines. 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 proposing
more stringent standards in order to protect public health with an
ample margin of safety. The proposed standards are expected to 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 is necessary at this time to revise the national
emission standards. The term ``facility-wide'' applies to facilities
with emissions associated with halogenated solvent cleaning activities
only.

DATES: Comments. Comments must be received on or before October 2,
2006.
    Public Hearing. If anyone contacts EPA requesting to speak at a
public hearing by August 28, 2006, a public hearing will be held
approximately 15 days following publication of this notice in the
Federal Register.

ADDRESSES: Comments. Submit your comments, identified by Docket ID No.
EPA-HQ-OAR-2002-0009, by one of the following methods:
     http://www.regulations.gov. Follow the on-line

instructions for submitting comments.
     E-mail<EMAIL_ADDRESS>     Fax:<PHONE_NUMBER>.
     Mail: Air and Radiation Docket, EPA, Mailcode: 6102T, 1200
Pennsylvania Ave., NW., Washington, DC 20460. Please include a
duplicate copy, if possible. We request that a separate copy of each
public comment also be sent to the contact person listed below (see FOR
FURTHER INFORMATION CONTACT).
    Hand Delivery: Air and Radiation Docket, EPA, Room B-102, 1301
Constitution Ave., NW., Washington, DC 20004. Such deliveries are only
accepted during the Docket's normal hours of operation and special
arrangements should be made for deliveries of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-HQ-OAR-
2002-0009. The EPA's policy is that all comments received will be
included in the public docket without change and may be made available
online at http://www.regulations.gov, including any personal

information provided, unless the comment includes information claimed
to be confidential business information (CBI) or other information
whose disclosure is restricted by statute. Do not submit information
that you consider to be CBI or otherwise protected through http://www.regulations.gov, or e-mail. The http://www.regulations.gov Web site

is an ``anonymous access'' system, which means EPA will not know your
identity or contact information unless you provide it in the body of
your comment. If you send an e-mail comment directly to EPA without
going through http://www.regulations.gov, your e-mail address will be

automatically captured and included as part of the comment that is
placed in the public docket and made available on the Internet. If you
submit an electronic comment, EPA recommends that you include your name
and other contact information in the body of your comment and with any
disk or CD-ROM you submit. If EPA cannot read your comment due to
technical difficulties and cannot contact you for clarification, EPA
may not be able to consider your comment. Electronic files should avoid
the use of special characters, any form of encryption, and be free of
any defects or viruses.
    Docket: All documents in the docket are listed in the http://www.regulations.gov
 index. Although listed in the index, some

information is not publicly available, e.g., 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.
Publicly available docket materials are available either electronically
in http://www.regulations.gov or in hard copy at the Air and Radiation

Docket, EPA/DC, EPA West, Room B-102, 1301 Constitution Ave., NW.,
Washington, DC. The Public Reading Room is open from 8:30 a.m. to 4:30
p.m., Monday through Friday, excluding legal holidays. The telephone
number for the Public Reading Room is<PHONE_NUMBER>, and the telephone
number for the Air and Radiation Docket is<PHONE_NUMBER>.
    Public Hearing: If a public hearing is held, it will be held at 10
a.m. at EPA's Environmental Research Center Auditorium, Research
Triangle Park, NC, or at an alternate site nearby.

FOR FURTHER INFORMATION CONTACT: Mr. H. Lynn Dail, Natural Resources
and Commerce Group (E143-03), Sector Policies and Programs Division,
EPA, 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,
Sector Based Assessment Group (C539-02), Health and Environmental
Impacts Division, EPA, Research Triangle Park, NC 27711; telephone
(919) 541-0502; fax number<PHONE_NUMBER>, e-mail address:
<EMAIL_ADDRESS>

SUPPLEMENTARY INFORMATION:
    Regulated Entities. The categories and entities potentially
regulated by the proposed rule include:

------------------------------------------------------------------------
                                                         Examples of
          Category               NAICS \1\ code          potentially
                                                     regulated entities
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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
proposed rule. This proposal directs an owner or operator of
halogenated solvent cleaning facilities to determine if whether the
applicability criteria in 40 CFR 63.460 of subpart T (1994 national
emission standards for Halogenated Solvent Cleaning) remains or whether
these proposed standards require the facility to operate under the
emission caps set forth. If you have any questions regarding the
applicability of the proposed standards to a particular entity, consult
the person listed in the preceding FOR FURTHER INFORMATION CONTACT
section.
    Submitting CBI. Do not submit this information to EPA through
http://www.regulations.gov or e-mail. Clearly mark the part or all of

the information that you claim to be CBI. For CBI information on a disk
or CD-ROM that you mail to EPA, mark the outside of the disk or CD-ROM
as CBI and then identify electronically within the disk or CD-ROM the
specific information that is claimed as CBI. In addition to one
complete version of the comment that includes information claimed as
CBI, a copy of the comment that does not contain the information
claimed as CBI must be submitted for inclusion in the public docket.
Information so marked will not be disclosed except in accordance with
procedures set forth in 40 CFR part 2.
    Public Hearing. Persons interested in presenting oral testimony or
inquiring as to whether a public hearing is to be held should contact
Ms. Dorothy Apple, Natural Resources and Commerce Group (E143-03),
Sector Policies and Programs Division, EPA, Research Triangle Park, NC
27711, telephone number:<PHONE_NUMBER>, e-mail address:
<EMAIL_ADDRESS>, at least 2 days in advance of the potential

date of the public hearing. Persons interested in attending the public
hearing also must call Ms. Apple to verify the time, date, and location
of the hearing. A public hearing will provide interested parties the
opportunity to present data, views, or arguments concerning the
proposed standards.
    Worldwide Web (WWW). In addition to being available in the docket,
an electronic copy of the proposed rule is also available on the WWW
through the Technology Transfer Network (TTN). Following signature, a
copy of the proposed rule will be posted on the TTN's 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.
    Outline. The information presented in this preamble is organized as
follows:

I. Background
    A. What is the statutory authority for regulating hazardous air
pollutants (HAP)?
    B. What is halogenated solvent cleaning?
    C. What are the health effects of halogenated solvents?
    D. What does the 1994 halogenated solvent cleaning NESHAP
require?
II. Summary of Proposed Requirements for New and Existing Major and
Area Sources
III. Rationale for the Proposed Rule
    A. What is our approach for developing residual risk standards?
    B. How did we estimate residual risk?
    1. How did we estimate the emission and stack parameters for
these sources?
    2. How did we estimate the atmospheric dispersion of the emitted
pollutants?
    3. How were cancer and non-cancer risks estimated?
    4. What factors are considered in the risk assessment?
    C. What are the results of the baseline risk assessment?
    D. What is our proposed decision on acceptable risk?
    E. What is our proposed decision on ample margin of safety?
    1. What risk reduction alternatives did EPA evaluate?
    2. What are the costs of the proposed alternatives?
    3. What regulatory options is EPA proposing?
    4. Rationale for Option 1
    5. Rationale for Option 2
    6. Comparison of Option 1 and 2
    F. What is EPA proposing pursuant to CAA Section 112(d)(6)?
    G. What is the rationale for the proposed compliance schedule?
IV. Solicitation of Public Comments
    A. Introduction and General Solicitation
V. 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 and Advancement Act

I. Background

A. What is the statutory authority for regulating hazardous air
pollutants (HAP)?

    Section 112 of the CAA establishes a two-stage regulatory process
to address emissions of hazardous air pollutants (HAP) from stationary
sources. In the first stage, CAA section 112(d) calls for us to
promulgate national technology-based emission standards for categories
of sources that emit or have the potential to emit any single HAP at a
rate of 10 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.
    CAA section 112(d)(6) then requires EPA to review these technology-
based 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 second stage in standard-setting 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 for each CAA section
112(d) source category whether the MACT standards protect public health
with an ample margin of safety. If the MACT standards for 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. The EPA must also adopt 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 natural resources * * *.''), but must
consider cost, energy, safety, and other relevant factors in doing so.

B. What is halogenated solvent cleaning?

    Halogenated solvent cleaning machines use halogenated solvents
(methylene chloride, perchloroethylene, trichloroethylene, 1,1,1,-
trichloroethane, carbon tetrachloride, and chloroform), 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 Code 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, a year
after compliance with the MACT occurred, and should reflect the
decreases in HAP emissions and demand that were expected due to
implementation of MACT control technologies and work practice
standards. Recent evidence on solvent usage suggests that the number of
sources in the source category may have declined further in the post-
MACT implementation years. An analysis of market data for halogenated
solvents showed that the demand for degreasing solvents declined
substantially in the 5 years following the implementation of MACT. From
1998 to 2003, the demand for PCE, TCE, MC, and TCA for degreasing
decreased by 39 percent, 35 percent, 23 percent, and 15 percent,
respectively. The halogenated solvents carbon tetrachloride and
chloroform are no longer used in this source category. The Montreal
Protocol, a treaty signed on September 16, 1987, phased-out the
production and consumption of these chlorofluorocarbons by January 1,
1996. The Protocol also phased out TCA. TCA has not been manufactured
for domestic use in the United States since January 1, 2002. Facilities
with essential products or activities are allowed to continue their use
of TCA, but for facilities with non-essential activities or products,
they were allowed to use remaining TCA stockpiles until depleted.
    There are two basic types of solvent cleaning machines: Batch
cleaners and in-line cleaners. Both cleaner types can be designed to
use either solvent at room temperature (cold cleaners) or solvent vapor
(vapor cleaners). The vast majority of halogenated solvent use is in
vapor cleaning, both batch and in-line. The most common type of batch
cleaner that uses halogenated solvent is the open-top vapor cleaner
(OTVC).
    Batch cleaning machines, which are the most common type, are
defined as a solvent cleaning machine in which individual parts or sets
of parts move through the entire cleaning cycle before new parts are
introduced. Batch cleaning machines include cold and vapor machines. In
batch cold cleaning machines, the material being cleaned (i.e., the
workload) is immersed, flushed, or sprayed with liquid solvent at room
temperature. Most batch cold cleaners are small maintenance cleaners
(e.g., carburetor cleaners) or parts washers that often use non-HAP
solvent mixtures for cleaning. Batch cold cleaning equipment sometimes
includes agitation to improve cleaning efficiency.
    In batch vapor cleaning machines, parts are lowered into an area of
dense vapor solvent for cleaning. The most common type of batch vapor
cleaner is the open-top vapor cleaner. Heating elements at the bottom
of the cleaner heat the liquid solvent to above its boiling point.
Solvent vapor rises in the machine to the height of chilled condensing
coils on the inside walls of the cleaner. The condensing coils cool the
vapor causing it to condense and return to the bottom of the cleaner.
Cleaning occurs in the vapor zone above the liquid solvent and below
the condensing coils, as the hot vapor solvent condenses on the cooler

workload surface. The workload or a parts basket is lowered into the
heated vapor zone with a mechanical hoist.
    Batch vapor cleaning machines vary greatly in size and design to
suit applications in many industries. Batch vapor cleaner sizes are
defined by the area of the solvent/air interface.
    Emissions from batch cold cleaning machines result from evaporation
of solvent from the solvent/air interface ``carry out'' of excess
solvent on cleaned parts, and other evaporative losses such as those
that occur during filling and draining. Evaporative emissions from the
solvent/air interface are continual whether or not the machine is in
use. These evaporative losses can be reduced by limiting air movement
over the solvent/air interface (e.g., with a machine cover or by
reducing external drafts) or by limiting the area of solvent air
interface (e.g., with a floating water layer). Emissions related to
solvent carry out occur only when the cleaning machine is in use. Carry
out emissions may be substantial, especially if excess solvent is not
allowed to drain back into the machine. Carry out includes solvent film
remaining on flat workload surfaces and liquid pooled in cavities.
Factors affecting the amount of carry out loss include the speed of
parts movement, workload shapes and materials, and work practices
(e.g., turning over parts to drain cavities).
    The closed-loop cleaning system is a type of batch cleaner with a
closed system capable of reusing solvent. Parts are placed inside a
vacuum chamber. Vapor or liquid solvent is pumped in the chamber to
clean the parts. Once cleaned, the parts are dried under vacuum and
removed; the solvent is removed and recycled. Because these systems are
constructed to maintain a vacuum, they have the potential to reduce
emissions up to 97 percent.
    Cold and vapor in-line (i.e., conveyorized) cleaning machines,
which include continuous web cleaners, employ automated parts loading
and are used in applications where there is a constant stream of parts
to be cleaned. In-line cleaners usually are used in large-scale
industrial operations (e.g., auto manufacturing) and are custom-
designed for specific workload and production characteristics (e.g.,
workload size, shape, and production rate). In-line cleaners clean
parts using the same general techniques used in batch cleaners: cold
in-line cleaners spray or immerse parts in solvent, and vapor in-line
cleaners clean parts in a zone of dense vapor solvent.
    Emissions from cold and vapor in-line cleaning machines result from
the same mechanisms (e.g., evaporation, diffusion, carryout) that cause
emissions from cold and vapor batch cleaning machines. However, the
emission points for in-line cleaners are different from those for batch
cleaners because of differences in machine configurations. In-line
cleaning machines are semi-enclosed above the solvent/air interface to
control solvent losses. In most cases, the only openings are the parts
entry and exit ports. These openings are the only emissions points for
downtime and idling modes. Carryout emissions add to emissions during
the working mode. Idling and working mode emissions from the in-line
cleaner are significantly less than emissions from an equally-sized
batch vapor cleaner. However, in-line cleaners tend to be much larger
than batch vapor cleaners. Some in-line cleaners have exhaust systems
that pump air from inside the cleaning machine to an outside vent.
Exhaust systems for in-line cleaners reduce indoor emissions from the
cleaning machine but increase solvent consumption.
    Continuous cleaners are a subset of in-line cleaners and 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 solvents?

    Methylene chloride, perchloroethylene, 1,1,1,-trichloroethylene
(TCA), and trichloroethylene are the primary halogenated solvents used
for solvent cleaning. Carbon tetrachloride and chloroform are no longer
used as degreasing solvents. Therefore, their health effects are not
discussed in this section. The four solvents still in use are described
below. 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.
    Methylene chloride is predominantly used as a solvent. The acute
effects of methylene chloride inhalation in humans consist mainly of
central nervous system effects including decreased visual, auditory,
and motor functions that may occur at or above 1-hour exposures of 690
mg/m\3\, but these effects are reversible once exposure ceases. The
effects of chronic exposure to methylene chloride suggest that the
central nervous system is a potential target in humans and animals.
ATSDR estimates that no adverse noncancer effects are likely in human
populations chronically exposed at or below 1 mg/m3. Human
studies are inadequate regarding methylene chloride and cancer.
However, animal studies have shown significant increases in liver and
lung cancer and benign mammary gland tumors following the inhalation of
methylene chloride. On this basis, EPA classified methylene chloride as
a Group B2, probable human carcinogen, with a cancer unit risk estimate
(URE) of 4.7 x 10-7 ([mu]g/m\3\)-1, when assessed
under the previous 1986 Cancer Guidelines. EPA is currently reassessing
its potential toxicity and carcinogenicity. All activities related to
this chemical reassessment are expected to be complete in late 2007.
    Perchloroethylene (PCE or tetrachloroethylene) is widely used for
dry-cleaning fabrics and metal degreasing operations. The main effects
of PCE in humans are neurological, liver, and kidney damage following
acute (short-term) and chronic (long-term) inhalation exposure. The
results of epidemiological studies evaluating the relative risk of
cancer associated with PCE exposure have been mixed; some studies
reported an increased incidence of a variety of tumors, while other
studies did not report any carcinogenic effects. Animal studies have
reported an increased incidence of liver cancer in mice, via inhalation
and gavage (experimentally placing the chemical in the stomach), and
kidney and mononuclear cell leukemia in rats.
    Although PCE has not yet been reassessed under the Agency's
recently revised Guidelines for Cancer Risk assessment, it was
considered in one review by the EPA's Science Advisory Board to be
intermediate between a ``probable'' and ``possible'' human carcinogen
(Group B/C) when assessed under the previous 1986 Guidelines. Since
that time, the U.S. Department of Health and Human Services has
concluded that PCE is ``reasonably anticipated to be a human
carcinogen,'' and the International Agency for Research on Cancer has
concluded that PCE is ``probably carcinogenic to humans.''

    Effects other than cancer associated with long-term inhalation of
PCE in worker or animal studies include neurotoxicity, liver and kidney
damage, and, at higher levels, developmental effects. To characterize
noncancer hazard in lieu of the completed Integrated Risk Information
System (IRIS) assessment, which is being revised, we used the Agency
for Toxic Substances and Disease Registry's (ATSDR) Minimum Risk Level
(MRL). This value is based on a study of neurological effects in
workers in dry cleaning shops, and is derived in a manner similar to
EPA's method for derivation of reference concentrations, including
scientific and public review. Based on these effects, EPA estimates
that no adverse noncancer effects are likely in human populations
chronically exposed at or below 0.27 mg/m\3\.
    The Agency's IRIS chemical assessment for PCE is currently being
revised. The current schedule indicates that a final IRIS determination
on PCE is not expected until 2008 at the earliest. Because EPA has not
yet issued a final IRIS document for PCE, to estimate cancer risk, we
used the California EPA (CalEPA) unit risk estimate (URE) of 5.9 x
10-6 (ug/m\3\)-1, as well as a URE value
developed by the EPA's Office of Prevention, Pesticides and Toxic
Substances (OPPTS) of 7.1 x 10-7 (ug/m\3\)-1. The
final IRIS reassessment may result in a URE that is different from
these two values. Among the available Acute Reference Levels (ARL), the
one-hour California Reference Exposure Level (a REL value of 240 mg/
m\3\) was considered the most appropriate to use in the assessment
because it may be used to characterize acute risk for exposure with an
exposure duration of one hour.
    Most of the trichloroethylene (TCE) used in the United States is
released into the atmosphere from industrial degreasing operations.
Acute and chronic inhalation exposure to trichloroethylene can affect
the human central nervous system, with symptoms such as dizziness,
headaches, confusion, euphoria, facial numbness, and weakness. Liver,
kidney, immunological, endocrine, and developmental effects have also
been reported in humans. Acute effects may occur at or above 1-hour
exposures of 700 mg/m\3\. CalEPA estimates that no adverse noncancer
effects are likely in human populations chronically exposed at or below
0.6 mg/m\3\. Animal studies have reported statistically significant
increases in kidney, lung, liver, and testicular tumors. EPA classified
trichloroethylene in Group B2/C, an intermediate between a probable and
possible human carcinogen, when assessed under the previous 1986 Cancer
Guidelines, but this classification has been withdrawn. CalEPA has
derived a cancer URE of 2.0 x 10-6 (ug/m\3\)-1
for TCE, which we used for our cancer risk assessment. EPA is currently
reassessing the cancer classification of trichloroethylene.
    In 1999, TCA was used as a solvent for degreasing up until it was
phased out in 2002. CalEPA estimates that no adverse noncancer effects
are likely in human populations chronically exposed to TCA at or below
1 mg/m\3\. EPA classified TCA in Group D, not classifiable as to human
carcinogenicity, when assessed under the previous 1986 Cancer
Guidelines. EPA is currently reassessing its potential toxicity
(related to chronic and less-than-lifetime exposures). All activities
related to chemical reassessment are expected to be complete in 2007.
Although production and use of TCA has been phased-out since 1998, a
declining quantity of TCA continued to be used until 2002, when all
production of TCA ceased, and eventually, facilities used TCA stock-
piles until depleted. However, an exemption to the phase-out allows a
few specialized facilities with essential activities or products to
continue its use of TCA. TCA was profiled in the noncancer chronic risk
assessment.
    The OPPTS toxicity profile for perchloroethylene (PCE) is published
in an EPA publication entitled, Cleaner technologies substitutes
assessment: professional fabricare processes. U.S. EPA Office of
Pollution Prevention and Toxics, Washington DC. EPA 744-B-98-001; June
1998. Complete toxicity profiles for the four HAPs may be obtained from
the following Web sites: EPA's OPPTS Web site for perchloroethylene at
http://www.epa.gov/dfe/pubs/garment/ctsa/fabricare.pdf; California EPA's Web site at http://www.oehha.ca.gov/air/hot_spots/index.html;
hha.ca.gov/air/hot_spots/index.html;
and the Agency for Toxic Substances and Disease Registry's Web site at
http://www.atsdr.cdc.gov/toxpro2.html.>;  Status reports for IRIS chemical reassessments are available at http://cfpub.epa.gov/iristrac/index.cfm.

pa.gov/iristrac/index.cfm.

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

    We promulgated national emission standards for halogenated solvent
cleaning (59 FR 61805, December 2, 1994) and required existing sources
to comply with the national emission standards by December 2, 1996. The
halogenated solvent cleaner NESHAP requires batch vapor solvent
cleaning machines and in-line solvent cleaning machines to meet
emission standards reflecting the application of the maximum achievable
control technology for major and area sources; area source batch cold
cleaning machines are required to achieve generally available control
technology. The rule regulates the emissions of the following
halogenated HAP solvents: MC, PCE, TCE, TCA, CT, and chloroform. In
1999, MC, PCE, TCE and TCA were the primary halogenated solvents used
for solvent cleaning. Although production and use of TCA has been
phased-out since 1998, a declining quantity of TCA continued to be used
until 2002, with either facilities depleting existing stockpiles past
2002 or facilities with essential products or activities continuing use
of TCA. CT and chloroform are no longer used as degreasing solvents.
    The promulgated standard includes multiple alternatives to allow
owners or operators maximum compliance flexibility. These alternatives
include:
     Control equipment standards--As many as 10 combinations of
emission control equipment, such as freeboard refrigeration devices and
working-mode covers may be installed.
     Idling-mode emissions standards--Compliance may be
demonstrated by maintaining monthly emission rates during the idling
mode below specified standards.
     Overall emission standards--Solvent use and disposal
records may be used to calculate average monthly emissions, which must
remain below specified numerical limits.
    If an owner or operator of a batch vapor or in-line cleaning
machine elects to comply with the equipment standard, they must install
one of the control combinations listed in the regulation, use an
automated parts handling system to process all parts, and follow
multiple work practices. As an alternative to selecting one of the
equipment control combinations listed in the regulation, an owner or
operator may demonstrate that the batch vapor or in-line cleaning
machine can meet the idling mode emission limit specified in the
standards. In addition to maintaining this idling mode emission limit,
the owner or operator of a batch vapor or in-line solvent cleaning
machine must use an automated parts handling system to process all
parts and comply with the work practice standards. A third alternative
for complying with these standards is to comply with the overall
solvent emissions limit. An owner or operator complying with the
overall solvent emissions limit is required to ensure that the
emissions from each

solvent cleaning machine are less than or equal to the solvent emission
levels specified in the standard. Under this alternative standard, an
owner or operator is not required to use an automated parts handling
system or to comply with the work practice standards.
    The batch cold cleaning machine standard is an equipment standard.
However, those owners or operators choosing the equipment options
without the water layer must also comply with work practice
requirements. There is no idling standard or overall solvent emissions
standard for batch cold cleaning machines. Batch cold cleaning machines
located at non-major sources are exempt from Title V permit
requirements.
    The halogenated solvent cleaning NESHAP was estimated to reduce
nationwide emissions of hazardous air pollutants (HAP) from halogenated
solvent cleaning machines by 77,400 Mg/yr (85,300 tons per year) or 63
percent by 1997 compared to the emissions that would result in the
absence of the standards.

II. Summary of the Proposed Requirements for New and Existing Major and
Area Sources

    Under the proposed standards, the requirements for all new and
existing, major and area sources are the same. In addition to the MACT
standard, the proposed revisions would require each facility to comply
with a facility-wide solvent emission limit. As defined by this
proposed rule, ``facility-wide solvent emissions'' are the combined
emissions of PCE, TCE, and MC from all of a facility's solvent cleaning
machines that are subject to the 1994 MACT standards (40 CFR Part 63,
subpart T). Under CAA section 112(f), EPA has the discretion to impose
residual risk standards on area sources regulated under generally
available control technologies (GACT). The area sources subject to GACT
in the halogenated solvent cleaning source category would not be
subject to today's proposed standards. These sources are cold batch
cleaners.
    The proposed rule would require the owner or operator of each
facility to ensure that their facility-wide solvent emissions from all
halogenated solvent cleaning activities are less than or equal to the
solvent emission limits specified in the proposed options and
summarized in Table 1 of this preamble. This approach gives the owner
or operator of the facility the flexibility to choose any means of
reducing the facility-wide emissions of PCE, TCE, and MC to comply with
facility-wide emission limit. The proposed options are in addition to
the existing NESHAP requirements and, therefore, all requirements of
the existing NESHAP remain in place.
    Table 1 shows two sets of facility-wide emission limits--option 1
and option 2. We are co-proposing both of these options and are
soliciting comment on which of these two options is most appropriate.
As can be seen in Table 1 of this preamble, each halogenated solvent
has an associated facility-wide emission limit. These limits are for
facilities that emit only a single halogenated solvent. If more than
one halogenated solvent is used, the owner or operator of the facility
must calculate the facility's weighted halogenated solvent cleaning
emissions using equation 1 and comply with the limit in the last row of
Table 1 of this preamble. Note that, depending on whether the CalEPA
URE or the OPPTS URE for PCE is used to derive the PCE limit, that
limit may be lower or higher. We request comment on the use of the
CalEPA URE, the OPPTS URE, or some other value in deriving the PCE
emission limit for the final rule.

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

Equation 1:

    (kgs of PCE emissions x A) + (kgs of TCE emissions x B) + (kgs of
MC emissions) = Weighted Emissions in kgs

    We developed a method for facilities using multiple HAP solvents to
determine their emission limit by calculating their MC-equivalent
emissions using the toxicity-weighted equation above. In the 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 either 1.5 or 12.5, depending on whether we
use the OPPTS URE or the CalEPA URE for PCE. The value for ``B'' is
4.25. We believe there may be other approaches to arriving at emissions
alternatives for multiple HAP use and we request comment on the use of
the MC-equivalency method, or other possible calculation methods that
we should consider, when establishing emission limits for facilities
using more than one of the listed HAP solvents. We also request comment
on whether the OPPTS URE, the CalEPA URE or some other value should be
used in the implementation of the emission cap chosen for the final
rule.
    Compliance with the emission limit is demonstrated by determining
the annual PCE, TCE, and MC emissions for all cleaning machines at the
facility. There is no additional equipment monitoring or work practice
requirements associated with the facility-wide annual emissions limit.
Annual emissions of these HAP 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 versus the level in the
final rule.
    We believe owners and operators currently have information
available to immediately determine if they would be in compliance with
today's proposed emissions limits. Current recordkeeping requirements
in 40 CFR subpart T section 63.467 require each owner and operator of
solvent cleaning machines to maintain, for 5 years, estimates of
solvent content and annual solvent consumption for each solvent
cleaning machine and any calculations showing how monthly emissions or
3-month rolling average emissions were calculated. Moreover, current
reporting requirements in 40 CFR subpart T Section 63.468 include an
initial notification report, an initial statement of compliance report,
annual compliance reports, and an exceedance report (required only when
an exceedance occurs). In the initial notification report, owners and
operators disclose an estimate of the annual halogenated HAP solvent
consumption for each solvent cleaning machine. Furthermore, owners and
operator submit annual reports that contain estimates of their solvent
consumption for each solvent cleaning machine used during the period.
    We believe that there are multiple ways in which facilities could
comply with the proposed rule. Our analysis also shows that some
affected facilities can easily reduce emissions and risks through
solvent switching. Solvent switching, in this case, is switching from a
high risk solvent to one with lower health risks. Facilities can also
reduce emissions by reducing solvent use, and by using careful work
practices and traditionally available control options to further reduce
emissions. Increased diligence in controlling lids, installing
freeboard chillers, increased drying times, installing closed loop
systems, and increasing the freeboard ratio would allow the higher
emitting higher risk facilities to achieve compliance with this
proposed standard. The available information indicates that solvent
switching, vapor capture, maintenance, reduced solvent use and limiting
cleaning runs would be the primary components of any small decrease in
costs.
    In summary, we are proposing two options that cap facility-wide
emissions at 40,000 and 25,000 kg/yr calculated as MC-equivalents.

III. Rationale for the Proposed Rule

A. What is our approach for developing residual risk standards?

    Section 112(f)(2)(A) of the CAA states that if the MACT standards
for a source emitting 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 * * * to less than 1-in-
a-million, the Administrator shall promulgate [residual risk]
standards * * * for such source category.''

    Halogenated solvent cleaning facilities subject to the proposed
amendments emit known, probable, and possible human carcinogens. The
docket for today's proposed rule contains documentation of the EPA's
determination that the risk to the individual most exposed to emissions
from halogenated solvent cleaning is expected to exceed 1-in-a-million.
Even if we were to quantitatively consider the uncertainty and
variability in the exposure and modeling assumptions used to derive our
estimate of the risk to the individual most exposed, such an analysis
is unlikely to change any decisions that would be made based on that
level of risk.
    Following our initial determination that the individual most
exposed to emissions from the source category considered exceeds a 1-
in-a-million individual cancer risk, our approach to developing
residual risk standards is based on a two-step determination of
acceptable risk and ample margin of safety. We followed the Benzene
NESHAP approach in making CAA section 112(f) residual risk
determinations.\1\ Our approach for this source category is the same
approach outlined in the National Emission Standards for the Benzene
NESHP Final Rule, (54 FR 38044, September 14, 1989.
---------------------------------------------------------------------------

    \1\ This is confirmed by the Legislative History to CAA Section
112(f); see, e.g., ``A Legislative History of the Clean Air Act
Amendments of 1990,'' vol. 1, page 877 (Senate Debate on Conference
Report) ``stating that: * * * the managers intend that the
Administrator shall interpret this requirement [to establish
standards reflecting an ample margin of safety] in a manner no less
protective of the most exposed individual than the policy set forth
in the ``Residual Risk Report to Congress, March 1999. EPA-453/R-99-
001, p. ES-11)''.
---------------------------------------------------------------------------

B. How did we estimate residual risk?

    The EPA's ``Residual Risk Report to Congress'' (EPA-453/R-99-011)
provides the general framework for conducting risk assessments to
support decisions made under the residual risk program. The approach
used to assess the risks associated with our halogenated solvent
cleaning facilities is consistent with the technical approach and
policies described in the Residual Risk Report to Congress. Details of
the risk assessment performed in support of this proposal are presented
below and provided in the risk document in the rulemaking docket.
1. How did we estimate the emission and stack parameters for these
sources?
    Three sources of data were used to characterize the source category
for the residual risk assessment: EPA's 1999 National Emissions
Inventory (NEI) database; a sample of MACT compliance reports obtained
from states and EPA regions; and information compiled from Clean Air
Act Title V permits. Together, these sources provided data for 2,672
unique cleaning machines at 1,167 unique facilities. The 1,167
facilities represent approximately 61 percent of the 1,900 total
facilities estimated to be in the source category.
    The majority of the data, approximately 90 percent, were obtained
from the 1999 NEI database, (i.e., the NEI provided data on 1,093
facilities). The types of data obtained from the NEI database include
machine type (from SCC codes and unit descriptions), HAP emissions
data, and stack characteristics. The compliance reports collected for
the residual risk assessment provided information for 195 cleaning
machines at 96 facilities. The types of data obtained from the
compliance report include machine types, machines sizes, solvent
consumption rates, HAP emissions data, compliance options, and control
equipment choices. We gathered machine-specific data for continuous web
cleaning machines from Title V permits and other sources. These data,
which included 74 cleaning machines at seven facilities, were added to
the cleaning machine data obtained from compliance reports.
    Halogenated solvent cleaning machines are co-located with many and
diverse types of industries. An analysis of MACT source category codes
in the 1999 NEI data found that approximately 74 percent of the 1,093
halogenated solvent cleaning sources in our database are co-located
with at least one other source category. Approximately 80 percent of
the halogenated solvent emissions from solvent cleaning machines
occurred at facilities where other source categories appeared to be co-
located. However, because of the diversity of co-located source
categories, this risk assessment evaluated the emissions coming from
the degreasing operations only and did not consider emissions of HAPs
that were identified

for co-located, non-degreasing operations.
    The residual risk assessment used HAP emissions data from the
assessment database described above, (i.e., the 1,167 facilities).
These data were used to estimate the baseline residual risks for the
facilities in the category and to evaluate regulatory options developed
to look at further HAP emission reductions. Nearly all of the data
reflects actual emissions (details of how EPA estimated emissions are
discussed in the Risk Assessment for Halogenated Solvent Cleaning
Source Category {Risk Assessment Support Document{time}  located in the
docket for this proposed rulemaking). In the few instances where we had
the data to estimate the MACT allowable emissions and to compare those
estimates with the emissions reported in NEI, the allowable emissions
were, on average, a factor of 2 higher.
    Compliance with the 1994 MACT is accomplished using one of three
compliance options. Only two of the compliance options are based on a
numerical limit and would allow estimates of MACT allowable emissions
to be calculated if information on machine size were available. For
these compliance options, allowable emission rates may exceed actual
emissions. For the control equipment compliance option which does not
include a numerical emission limit, allowable emissions cannot be
estimated but could be considered equivalent to actual emissions.
Approximately 58 percent of the facilities in our assessment (i.e.,
those using the control equipment compliance option) would fall into
this category.
    Data obtained from MACT compliance reports required processing to
prepare emissions rates for use in the residual risk assessment. The
types of data and level of detail in the compliance reports varied
depending upon which of the three MACT compliance options were chosen,
the specific report type available (e.g., initial notification report,
annual compliance reports) available, and the report format. To use as
much of the available information as possible, emission rate estimation
methods were developed for various combinations of available data (see
Appendix A in the Risk Assessment Support Document for details). These
methods were used to estimate actual emissions rates for each cleaning
machine. If more than one machine existed at a facility, the machine-
level emission estimates were added together to yield facility-level
totals.
    NEI provides emission data for each HAP and emission point at a
source and are reported in kilograms per year. For the residual risk
assessment, NEI emission rates were used as obtained from NEI. No
further processing of the data (e.g., to standardized units) was
needed. However, total facility-level emissions were calculated for
each HAP when sources had multiple degreasing emission points (i.e.,
multiple degreasing machines).
    To fully represent the national coverage of these sources, we
scaled results from the 1,167 facilities identified in our assessment
database to the 1,900 facilities currently estimated to be in the
source category. When this was done, the total estimated HAP emissions
from the source category were approximately 16,000 tons per year. These
emissions consist of 38 percent TCA, 35 percent TCE, 15 percent PCE,
and 12 percent MC. The total estimated carcinogenic HAP emissions (MC,
TCE and PCE) from the source category are approximately 9,700 tons/
year.
    MC emissions in 1999 were just over 1,300 tons from about 218
facilities, while in 2002, about 400 tons were emitted from 194
facilities, representing about a 70 percent decrease in emissions.
About 11 percent of facilities using MC in 1999 ceased using MC or
ceased degreasing operations altogether.
    In 1999, TCE emissions were 3,000 tons from about 320 facilities.
In 2002, TCE emissions had decreased 24 percent to 2,300 tons; however,
the number of facilities using TCE increased 10 percent to 357.
    In 1999, PCE emissions were estimated at about 1,300 tons from
about 200 facilities, however by 2002, PCE emissions had increased
approximately 73 percent to about 2,200 tons. There was a 10 percent
drop in the number of facilities using PCE in 2002.
    In 1999, about 3,700 tons of TCA were emitted from about 565
facilities. In 2002, TCA emissions were about 2,300 tons from 473
facilities, representing a 38 percent decrease in emissions and a 16
percent decrease in facilities using TCA.
    In 1991, TCA dominated use with 62 percent of the halogenated
solvent degreasing demand. By 1998, the demand for TCA had decreased by
87 percent. In a critical period between 1991 and 2002, TCA was being
phased out while remaining stock-piles at facilities with non-essential
activities were being used until depleted. In the 2002 NEI, there were
decreases in emissions of TCA, MC and TCE (by about 1,400 tons, 900
tons, and 700 tons, respectively) compared to 1999 NEI). From 1999 to
2002, emissions of PCE increased 73 percent (by about 900 tons).
Overall emissions data for the total of all four HAP from 1999 to 2002
indicated a 23 percent reduction in total emissions and an 8 percent
decrease in the number of facilities.
    Therefore, although it appears that between 1999 and 2002,
decreases in use of TCA, MC and TCE were partially offset by increases
in PCE use. This was due to switching HAP solvents, switching to other
non-HAP cleaning technologies, and elimination of solvent cleaning
altogether.
2. How did we estimate the atmospheric dispersion of emitted
pollutants?
    A nationwide, multi-facility version of EPA's Human Exposure Model,
HEM-Screen, was used to assess chronic exposure and risk. HEM-Screen
contains an atmospheric dispersion model with meteorological data and
year 2000 population data at the census block level from the U.S.
Bureau of Census. HEM-Screen includes meteorological data for 348
stations across the U.S. The model selects the meteorological data for
the station closest to each facility and uses this to estimate long-
term (i.e., annual average or greater) ambient concentrations of
pollutant air emissions for nodes on a radial grid surrounding each
facility. HEM-Screen then estimates concentrations at individual census
block centroid locations within this grid from the modeled
concentration results for grid nodes.
    For assessment of risk and hazard from chronic exposures, it was
assumed that the total annual emissions derived for each facility were
evenly distributed over the course of a year (i.e., a constant emission
rate).
    Although the HEM-Screen model can accommodate source-specific
release parameters, the same values were used for stack height, stack
diameter, exit gas velocity, and exit gas temperature for all sources.
The release parameters used for the risk assessment were derived from
data obtained from the 1999 NEI. All emissions in the analysis were
modeled as point source releases emitted from vertical stacks. The 1999
NEI includes release parameters for approximately 611 (out of the
1,093) facilities. The arithmetic mean values for each parameter were
used in this analysis as representative values for stack height, stack
diameter, exit gas velocity, and exit gas temperature. A maximum
modeling radius of 20 km around each facility was used, and flat
terrain was assumed for all facilities (e.g., no complex terrain was
included in the modeling).

    No adjustments were made to the estimated ambient concentrations
for reactivity of the HAPs being assessed. The exposures of most
interest for this chronic assessment (i.e., exposures that occur at the
point of maximum impact and other exposures that result in appreciable
cancer risks) occur in the immediate vicinity of the source and within
a short time period of release (i.e., minutes). Therefore, the impact
of reactivity of the HAPs is relatively insignificant in the context of
this exposure scenario.
3. How were cancer and noncancer risks estimated?
    The residual risk analysis addresses halogenated solvent cleaning
machines subject to the 1994 MACT standards (40 CFR Part 63, subpart T)
and estimates potential risks due to HAP emissions from sources that
emit one or more of the regulated HAPs that are still used (i.e., MC,
PCE, TCE and TCA). The risk assessment did not include the HAPs carbon
tetrachloride and chloroform because their use was phased out in 1996.
    The assessment only considered the inhalation pathway as the
primary route of exposure for humans because all of the four remaining
HAPs are highly volatile compounds. In addition, multimedia fugacity
modeling results indicate that the majority (over 99 percent) of each
of these four source category HAP partitions preferentially to air
rather than water, soil, or sediment (Risk Assessment Support
Document). Some persistent and bioaccumulative (PB) substances can also
pose human health risks via exposure pathways other than inhalation.
EPA has developed a list of PB HAPs based on information developed
under the Pollution Prevention Program, the Great Waters program, and
the Toxics Release Inventory and additional analysis conducted by
OAQPS. None of the four HAPs found in halogenated solvent cleaning
machine vapors are included on this list. Consequently, exposures to
these four HAPs via non-inhalation pathways were assumed to be minimal
for this source category, and a quantitative risk characterization for
multi-pathway exposures to humans was not carried out as a part of the
residual risk assessment.
    We evaluated the potential for these HAPs to pose risks to the
environment by conducting a screening-level ecological risk assessment
for the baseline scenario. This assessment was intended to determine if
HAPs emitted from these facilities pose a risk to ecological receptors
including threatened and endangered species. The scope of the
ecological screen was based on the fact that the HAPs emitted are all
volatile and were shown to preferentially partition to air rather than
soil or water, (i.e., the majority of the HAPs emitted (over 99
percent) will remain in the atmosphere rather than deposit onto soil,
plants, or aqueous environments. A more detailed explanation of this
screening assessment may be found in the Residual Risk support
document.
    The analysis estimated the potential for emissions from this source
category to result in increased cancer risk and chronic and acute
(i.e., one-hour) non-cancer hazard. Table 2 of this preamble outlines
the cancer and chronic non-cancer dose-response values we used on the
analysis.

                          Table 2.--Cancer and Chronic Non-Cancer Dose-Response Values
----------------------------------------------------------------------------------------------------------------
                                                                  Chronic reference      Cancer Unit Risk  (URE)
                                                               concentration or (RfC)    Estimate ([mu]g/m\3\)-1
                             HAP                               similar value (mg/m\3\) -------------------------
                                                             --------------------------
                                                                 Value        Source       Value        Source
----------------------------------------------------------------------------------------------------------------
Methylene Chloride..........................................          1.0        ATSDR      4.7E-07         IRIS
Perchloroethylene...........................................         0.27        ATSDR      5.9E-06      CAL and
                                                                                7.1E-07        OPPTS
Trichloroethylene...........................................          0.6          CAL      2.0E-06          CAL
1,1,1,-Trichloroethane......................................          1.0          CAL            -           -
----------------------------------------------------------------------------------------------------------------
Notes:
Source: EPA's air toxics Web site at http://www.epa.gov/ttn/atw/toxsource/summary.html, table 1 (values for

  assessing long-term inhalation risks) dated February 28, 2005. Specific source abbreviations: IRIS = EPA's
  Integrated Risk Information System; ATSDR = Agency for Toxic Substances and Disease Registry: CAL = California
  Environmental Protection Agency; OPPTS = Office of Prevention, Pesticides and Toxic Substances. The dash (-)
  for 1,1,1,-trichloroethane indicates that there are no data available at this time to indicate that this HAP
  is a carcinogen: the current EPA weight-of-evidence for carcinogenicity for this HAP is ``D'' (not
  classifiable). This HAP was not considered in the risk analysis for carcinogenic effects.

    Estimates of maximum individual cancer risk and chronic noncancer
hazard index (HI) were calculated for each census block around each
source by multiplying the long-term concentrations at each block by the
appropriate cancer URE and summing or by dividing those concentrations
by the appropriate reference concentration (RfC) and summing,
respectively. The total number of people exposed at various risk and
chronic HI levels were compiled to provide a distribution of population
risks.
    Acute (short-term) exposures to HAPs were estimated using EPA's
SCREEN3 model. SCREEN3 is a single source Gaussian plume model which
predicts the off-site maximum, short-term (one-hour) ambient
concentrations of emitted HAPs at any distance from the source
irrespective of population locations. To estimate maximum short-term
emission rates, annual emission rates were adjusted using an assumed
operating schedule of 8 hours/day, 260 days/year. The receptor location
evaluated for the acute exposure analysis assumed that individuals may
spend brief amounts of time at any location around a facility even
though they may not reside in those locations. The maximum one-hour
ambient concentrations were compared to acute non-cancer dose-response
values to obtain an estimate of the potential for acute non-cancer
hazard.
4. What factors are considered in the risk assessment?
    The risk assessment was designed to generate a series of risk
metrics that would provide information for a regulatory decision. The
metrics include both the maximum individual risk (MIR) and the
population distribution of risk, the latter providing perspective on
the potential public health impact by addressing each of the following
questions:

     How many people living around the halogenated solvent
cleaning facilities have potential risks greater than 1-in-a-million
and other risk levels?
     What is the estimated cancer incidence in the population
due to emissions from these facilities?
    Background exposures from other local or long-distance sources were
not considered in the determination of incremental residual risk. To
estimate the maximum individual risk (MIR), we assumed that people were
continuously exposed for a lifetime of 70 years to the model-predicted
ambient concentration at a census block around that facility. To better
estimate the distribution of exposures and risks across the population,
we developed an approach using a Monte Carlo simulation method (see
Appendix F of the Risk Assessment Support Document for details) which
accounts for variations in residency time.

C. What are the results of the baseline risk assessment?

    The baseline residual risk assessment for the halogenated solvent
cleaning source category used HAP emissions data from an assessment
database that included 1,167 sources. This assessment database
represents approximately 61 percent of the 1,900 facilities in the
source category. Estimates of maximum individual cancer risk and
chronic non-cancer hazard as well as distributions of cancer risks and
noncancer hazards across the exposed populations were calculated for
each facility. Results presented in this section have been scaled-up
proportionally to reflect results for the 1,900 facilities in the
source category. In addition, the risk results for the population risk
distributions are estimated to reflect varying exposure durations due
to the variability in residency times.
    Table 3 of this preamble summarizes the estimated lifetime cancer
risk results for the baseline level of emissions. The table shows the
number of people in the exposed population and the number of
halogenated solvent cleaning facilities that are associated with
various levels of lifetime cancer risk. Depending on which cancer
potency value is used for PCE, the highest risk to an individual living
in the vicinity of any of the halogenated solvent cleaning facilities
(the MIR) is between 90-in-a-million and about 200-in-a-million. For
the exposed population within 20 kilometers to the facilities, the
number of people with risks greater than or equal to 1-in-a-million is
as high as 5,900,000 people (using the CalEPA URE for PCE), with
between zero and 90 of these exposed to risks greater or equal to 100-
in-a-million. The annual cancer incidence is estimated to be between
0.2 and 0.4 cases per year. The numbers of facilities in the source
category which pose various levels of maximum individual lifetime
cancer risks are presented in Table 3 of this preamble (using the
CalEPA potency for PCE). These results show that source category
emissions from 539 facilities (approximately 28 percent of the sources
in the source category) were estimated to pose a maximum incremental
increase in lifetime cancer risk at or above 1-in-a-million. Of the 539
facilities, 124 were found to pose a maximum cancer risk greater than
or equal to 10-in-a-million and seven of these facilities were
estimated to pose a maximum cancer risk of 100-in-a-million or more.
Six-hundred ninety facilities emit only the non-carcinogen TCA and,
therefore, pose no cancer risk. The estimated numbers of facilities
above each risk level will decrease using the OPPTS URE for PCE.

   Table 3.--Population Risk Distribution and Number of Facilities at
  Various Levels of Risk--Baseline (Scaled to National Level)\1\--Uses
                    CalEPA Cancer Potency for PCE \6\
------------------------------------------------------------------------
                                                             Number of
                                                           facilities in
                                                            the source
                                          National-scale   category with
  Estimated lifetime cancer risk (in-a-   population \2\      maximum
                million)                        \3\       estimated risk
                                                              at the
                                                             Specified
                                                             level \4\
------------------------------------------------------------------------
>=100...................................              86               7
>=10 to < 100...........................          42,000             117
>=1 to < 10.............................       5,900,000             415
< 1 or no cancer risk (i.e., emit non-        200,000,000      \5\ 1,361
 carcinogen only).......................
------------------------------------------------------------------------
\1\ Represents the estimated numbers of people residing in census blocks
  with concentrations associated with risks at the designated risk
  level.
\2\ National-scale population estimated for this source category by
  multiplying the populations at the specified cancer risk level by
  1,900/1,167. Population counts have been rounded.
\3\ These population numbers are estimated to reflect residency time
  (exposure duration) variations.
\4\ Estimated by multiplying the number of sources at the specified
  cancer risk level (in Table B-1 of the Risk Assessment Support
  Document) by 1,900/1,167.
\5\ Calculated as 671 (sources at <  1 in-a-million risk) plus 690
  (sources that emit the non-carcinogen TCA only).
\6\Use of OPPTS URE for PCE will lower risk impacts.

    We also evaluated the potential for adverse health effects other
than cancer. Calculated chronic noncancer HIs were below 1 for all
1,167 facilities included in the risk assessment. The highest HI was
estimated to be 0.2. Given these results, it is expected that chronic
non-cancer HIs would be below one for all 1,900 facilities in the
source category.
    An ecological screening assessment to assess the inhalation risk to
potential terrestrial receptors was conducted to determine if there
were any potentially significant ecological effects that warranted a
more refined level of analysis. Maximum long-term air concentrations of
HAPs at the most exposed census block centroid were used as the
exposure concentrations, and estimated exposure concentrations were
compared to health protective ecological toxicity screening values.
Calculated hazard quotients associated with terrestrial ecological
receptors were well below one for all HAPs at all facilities. Because
of the health-protective assumptions used in this assessment, and the
fact that these HAPs are not persistent, bioaccumulative, or likely to
deposit on soil, plants, or water, it is believed that the ecological
screening values developed would also be protective of ecological
receptors that are threatened or endangered.
    We acknowledge that there are uncertainties, as well as
conservatism in various aspects of risk assessment due to the use of
some modeling and exposure assumptions. Specific possible

uncertainties in the risk assessment include: The size of the source
category, use of actual versus allowable emissions, lack of source
specific data on peak emissions, and modeling uncertainties (e.g.,
meteorology, emission point locations, release parameters, urban versus
rural dispersion, population size and exposure, co-location issues, and
dose response values). A detailed analysis of each of the possible
sources of uncertainty in the risk analysis is contained in the Risk
Assessment Support Document, available in the docket for this
rulemaking.

D. What is our proposed decision on acceptable risk?

    In the 1989 Benzene NESHAP (54 FR 38044, September 14, 1989), the
first step of the ample margin of safety framework is the determination
of acceptability (i.e., are the estimated risks due to emissions from
these facilities ``acceptable''). This determination is based on health
considerations only. The determination of what represents an
``acceptable'' risk is based on a judgment of ``what risks are
acceptable in the world in which we live'' (54 FR 38045, September 14,
1989), quoting the Vinyl Chloride decision, recognizing that our world
is not risk-free.
    In the 1989 Benzene NESHAP (54 FR 38044, September 14, 1989), we
determined that a maximum individual risk of approximately 100-in-a-
million should ordinarily be the upper end of the range of acceptable
risks associated with an individual source of emissions. We defined the
maximum individual risk as the estimated risk that a person living near
a plant would have if he or she were exposed to the maximum pollutant
concentrations for 70 years. We explained that this measure of risk is
an estimate of the upper bound of risk based on health protective
assumptions, such as continuous exposure for 24 hours per day for 70
years. We acknowledge that maximum individual risk ``does not
necessarily reflect the true risk, but displays a conservative risk
level which is an upper bound that is unlikely to be exceeded.''
    Understanding that there are both benefits and limitations to using
maximum individual risk as a metric for determining acceptability, the
Agency acknowledged in the 1989 Benzene NESHAP (54 FR 38044, September
14, 1989), that ``consideration of maximum individual risk * * * must
take into account the strengths and weaknesses of this measure of
risk.'' Consequently, the presumptive risk level of 100-in-a-million
provides a benchmark for judging the acceptability of maximum
individual risk, but does not constitute a rigid line for making that
determination. In establishing a presumption for the acceptability of
maximum individual risk, rather than a rigid line for acceptability, we
explained in the Benzene NESHAP that risk levels should also be weighed
with a series of other health measures and factors, discussed below.
    We estimate that the maximum individual lifetime cancer risk
(discussed below) associated with the 1994 national emission standards
for halogenated solvent cleaning is between 90 and 200-in-a-million. In
making the decision on the acceptability of the MIR risk level seen in
this assessment, the Benzene NESHAP explains that additional factors
may be considered along with the MIR. These factors can include the
number of people exposed within each individual lifetime risk range,
associated incidence of cancer, the policy assumptions and
uncertainties, the weight of the scientific evidence for human health
effects and other quantified or unquantified health effects. The
principal reasons that lead us to believe that the MIR is acceptable
are the following: the maximum risk could be as high as 90 to 200 in-a-
million, just above the presumptive acceptable level; at least 95
percent of the exposed population have risks below 1-in-a-million; at
most, only about 90 people in the exposed population near only 7 of the
1,900 facilities are estimated to be exposed at risk levels above 100
in-a-million; and the annual incidence of cancer resulting from the
limits in the 1994 national emission standards is between 0.2 and 0.40
cases per year. In addition, no significant noncancer health effects or
adverse ecological impacts are anticipated at this level of emissions.
    Therefore, we have decided that the risks associated with the
limits in the 1994 national emission standards are acceptable.

E. What is our proposed decision on ample margin of safety?

    In the second step of the ample margin of safety framework we
considered setting standards at a level which may be equal to or lower
than the acceptable risk level and which protects public health with an
ample margin of safety. In making this determination, we considered the
estimate of health risk and other health information along with
additional factors relating to the appropriate level of control,
including costs and economic impacts of controls, technological
feasibility, uncertainties, and other relevant factors.
1. What risk reduction alternatives did EPA evaluate?
    Six emission levels were developed to evaluate reductions in
residual risk if post-MACT emissions (i.e., baseline emissions) were
controlled further. The emission levels are not based on specific
emission control technologies or practices. The alternatives are a
range of maximum facility-wide emissions levels (emission limits or
``caps''). The emission levels would apply to the total emissions from
all of a facility's solvent cleaning machines that are subject to the
1994 MACT standards (40 CRF Part 63, subpart T). We believe that
solvent-switching and traditional technologies and practices,
implemented for further post-MACT control of HAP emissions, could
achieve these emissions levels.
    Emission levels for the proposed regulatory options were derived
based on the risk assessment results for the baseline level. To develop
the proposed risk-based alternatives, all emissions rates in the
assessment database were first converted to MC-equivalents based on the
relative cancer potency of the HAPs emitted. The cancer potency-
weighted MC-equivalent emissions rate was calculated as the estimated
emissions for the HAP in kg/yr or lb/yr times the unit risk estimate
(URE) for the HAP divided by the URE for MC.
    For the purpose of calculating MC-equivalent emissions as well as
the risk impacts of the various control scenarios, we have used the
upper end of the URE range (CalEPA) for PCE. We also describe how the
risk impacts might change if the OPPTS URE is used. For purposes of
implementing any control option in the final rule, we take comment on
the use of the OPPTS URE, the CalEPA URE, or some other value in
implementing the final rule.
    The six levels 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).
     40,000 level--Sources would reduce MC-equivalent emissions
to no more than 40,000 kg/yr (88,000 lbs/yr).
     25,000 level--Sources would reduce MC-equivalent emissions
to no more than the 25,000 kg/yr (55,000 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 6,000 kg/yr (13,200 lbs/yr).
    Table 4 of this preamble shows that the decrease in MIR ranges from
75 percent with a 100,000 kg/yr emission level (i.e., from 200-in-a-
million baseline to 50-in-a-million) to 99 percent with an emission
level of 6,000 kg/yr (i.e., from 200-in-a-million baseline to 3-in-a-
million). The corresponding annual incidence estimates decrease over
the range from 35 percent for the 100,000 kg/yr emission level to 90
percent for the 6,000 kg/yr level. Likewise, there are large shifts in
the number of people with risks greater than or equal to one-in-a-
million to below one-in-a-million. The reduction in population with
risks greater than or equal to one-in-a-million ranges from 66 percent
for the 100,000 kg/yr emission level to over 99 percent for the 6,000
kg/yr level.
    Table 5 of this preamble presents the number of facilities at
estimated cancer risk levels for the emission levels. Baseline results
are provided for comparison. Numbers represent national-scale estimates
(i.e., the numbers of facilities were scaled by a factor of
approximately 1.6) and the higher-end of the cancer potency range
(CalEPA) for PCE was used.

                                               Table 4.--Cancer Risk Results--Baseline vs. Emission Levels
                                                               [Scaled to National Level]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                 Baseline              Emission Levels (max MC-equivalent emissions in kg/yr)
                                                              ------------------------------------------------------------------------------------------
                     Cancer risk results                                                                Proposed     Proposed
                                                                   (no        100,000       60,000      option 1     option 2      15,000       6,000
                                                                 control)                                40,000       25,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
Maximum Individual Risk (in-a-million).......................          200           50           30           20           10            8            3
Annual Incidence.............................................         0.40         0.26         0.21         0.17         0.13         0.09         0.04
Estimated Lifetime Cancer Risk (in-a-million)................                            Estimated National Population \1\ \2\
>= 1 to < 10.................................................    5,900,000    2,000,000    1,200,000      630,000      200,000      200,000        8,200
>= 10 to < 100...............................................       42,000        5,100        1,400          700           67            0            0
>= 100.......................................................           86            0            0            0            0            0            0
                                                              ------------------------------------------------------------------------------------------
Total Population at >= 1.....................................    5,942,086    2,005,100    1,201,400      630,700      200,067      200,000       8,200
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ National population estimated for this source category by multiplying the populations at the specified cancer risk level by 1,900/1,167. Population
  counts for the individual risk bins have been rounded to two significant figures.
\2\ These population numbers reflect residency time (exposure duration) variations.

                                 Table 5.--Number of Facilities at Various Levels of Risk--Baseline vs. Emission Levels
                                                               [Scaled to National Level]
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                      Number of Facilities in the Source Category at the Estimated Risk Level \1\
                                                              ------------------------------------------------------------------------------------------
                                                                 Baseline              Emission Levels  (max MC-equivalent emissions in kg/yr)
        Estimated Lifetime Cancer Risk  (in-a-million)        ------------------------------------------------------------------------------------------
                                                                                Proposed     Proposed
                                                                    (no       100,000       60,000      Option 1     Option 2      15,000       6,000
                                                                control)                                 40,000       25,000
--------------------------------------------------------------------------------------------------------------------------------------------------------
>= 100.......................................................            7            0            0            0            0            0            0
>= 10 to < 100...............................................          117           85           57           29            7            0            0
>= 1 to < 10.................................................          415          453          477          501          492          461          239
<  1 or no cancer risk (i.e., facilities emit non-carcinogen          1,361        1,362        1,366        1,369        1,402        1,439       1,660
 only) \2\...................................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
Notes:
\1\ Estimated by multiplying the number of facilities at the specified cancer risk level by 1,900/1,167.
\2\ Calculated as facilities at <  1-in-a-million risk plus 690 (facilities that emit the non-carcinogenic TCA only).

    We have not at this time estimated population risks for these
scenarios using the lower end of the cancer potency range (OPPTS) for
PCE. However, if we had, the following would be observed:
     Baseline MIR for the source category will drop to 90, but
MIR values for each of the control scenarios will remain roughly the
same--this is due to the fact that, with a toxicity-equivalent emission
cap, MIR becomes directly proportional to MC-equivalent emissions (see
Table 4 of this preamble).
     Baseline cancer incidence will drop by about half, as will
that for each of the control scenarios.
     Population numbers above 1-in-a-million will drop, but we
cannot say how much.
     The numbers of facilities affected by each control
scenario will drop, as some PCE emitters will already fall below the
emissions cap at baseline.
    For the two proposed options, we will calculate refined population
and facility risk estimates using the OPPTS URE values for PCE in the
final rule.
2. What are the costs of the proposed alternatives?
    The second step in the residual risk decision framework is the
determination of standards with corresponding risk levels that are
equal to or lower than the acceptable risk level and that protect
public health with an ample margin of safety. In the ample margin
decision, the Agency considers all of the health risk and other health
information considered in the first step. Beyond that information, EPA
considers additional factors relating to the appropriate level

of control, including costs and economic impacts of controls,
technological feasibility, uncertainties, and any other relevant
factors. As indicated above in Tables 4 and 5 of this preamble, we
developed a range of emission levels and assessed their corresponding
risk to determine the public health significance of possible further
control. Before selecting our two proposed options, we considered the
costs of each of the six alternative emission levels in providing
various degrees of emission reduction. Table 6 of this preamble
summarizes the costs, emission reductions, and the incremental costs
for the control alternatives. When estimating the cost impacts for the
various alternatives, the CalEPA URE for PCE was used to calculate MC-
equivalents. Use of the OPPTS value will reduce capital costs and
solvent saving for each of the alternatives.

                                   Table 6.--Costs for Emission Level Options
----------------------------------------------------------------------------------------------------------------
                                                          Total                             Total
                                                        Annualized               Total      Annual
                                              Total    Capital and  Total HAP    Annual    Emission  Incremental
 Emission Limit Alternative MC-equivalent    Capital    Operation    Emission   Solvent    Control     Cost per
                   kg/yr                    Costs  ($      and      Reduction  (Savings)   Costs or   Ton of HAP
                                             million)  Maintenance    (tons/       ($     (Savings)    ($/ton)
                                                         Cost  ($      yr)      million)      ($
                                                         million)                          million)
----------------------------------------------------------------------------------------------------------------
1,000,000.................................       21.7         2.1       4,031      (7.4)      (5.2)     (1,292)
60,000....................................       31.5         3.0       4,903      (9.1)      (5.9)       (826)
40,000....................................       50.9        $4.9       5,911     (11.1)      (5.9)          16
25,000....................................       79.8         7.6       6,778     (12.8)      (4.9)       1,156
15,000....................................      120.7        11.5       7,674    ($14.6)      (2.8)       2,400
6,000.....................................      192.9        18.3       8,595     (16.4)        2.4       5,549
----------------------------------------------------------------------------------------------------------------

    To develop our cost estimates we identified a suite of traditional
control alternatives that would both reduce emissions beyond the MACT
and lower the cancer risk associated with the emissions. Two of the
controls are retrofit controls that can be added to existing cleaning
machines, three controls are solvent switching scenarios that reduce
cancer risk through use of a less toxic solvent, and one control
requires the replacement of existing equipment with a new vacuum-to-
vacuum cleaning machine.
    The development of the cost estimates for the solvent switching
scenarios considered changes in the cost of the solvent, changes in
solvent consumption rates, changes in energy requirements, costs for
equipment modifications, and changes in productivity. Capital costs
were scaled to 2004 dollars and were annualized assuming a 15-year
equipment lifetime and a 7 percent interest rate. The solvent switching
scenarios, their costs, and impacts are fully discussed in a separate
memorandum titled ``Evaluation of the Feasibility, Costs, and Impacts
of Switching from a Halogenated Solvent with a High Cancer Unit Risk
Value to a Halogenated Solvent with a Lower Cancer Unit Risk Value''
(National Cost Impacts Memorandum), which is in the docket for this
rulemaking.
    Costs for the vacuum-to-vacuum cleaning machines are based on
vendor estimates obtained in 2005. The vacuum-to-vacuum cleaning
machine capital costs were based on the replacement of a solvent
cleaning machine with a solvent-air interface area of 2.5 m\2\, which
is the average size of the solvent cleaning machines for which we have
size data. Since vacuum-to-vacuum cleaning machines do not have a
solvent-air interface, it was necessary to correlate the solvent-air
interface area of the old machine to the cleaning capacity of the new
vacuum-to-vacuum cleaning machine. The cost determination methods are
contained in the National Cost Impacts Memorandum, located in the
docket. Capital costs were annualized based on a 20-year equipment
lifetime and a 7 percent interest rate. The 20-year equipment lifetime
was determined based on information from equipment manufacturers. It
was determined that a 97 percent reduction in emissions would result
from switching from an existing solvent cleaning machine to a vacuum-
to-vacuum cleaning machine.
    The costs for the retrofit controls were based on vendor estimates
obtained in 2005 (Table A-1 and Table A-2 in the National Cost Impacts
Memorandum). The capital costs were based on equipment for a solvent
cleaning machine with a solvent-air interface area of 2.5 m\2\, which
is the average size of the solvent cleaning machines in the database
for which size data are available. The annualized capital costs were
based on a 15-year equipment lifetime and a 7 percent interest rate. A
50 percent emission reduction is expected to result from the addition
of a 1.0 Freeboard Ratio (FBR), Working Mode Cover (WC), and Freeboard
Refrigeration Device (FRD) control combination. A 30 percent emission
reduction is expected to result from the addition of a 1.5 FBR. These
percent emission reductions were calculated using emissions reduction
estimates and estimation procedures that were developed for the NESHAP.
    For each control alternative, the affected facilities (i.e., the
facilities that must reduce emissions) were identified from the
degreasing database based on whether the combined emissions of PCE,
TCE, and MC exceeded the emission limit alternative being evaluated. If
multiple solvents were emitted from a facility the emissions of each
pollutant were weighted and totaled using equation 1.
    Once the necessary percent reduction was known for each facility,
the compliance methods such as solvent switching, control equipment
retrofits and machine replacement were applied to each unit in order to
bring each facility into compliance with the appropriate limits. We
recalculated the required percent reduction after the application of
each control. For facilities with multiple units, several different
combinations of controls across the units often had to be tried before
a level of control that met the limits was achieved. To aid in the
assigning of controls to specific units, a control decision matrix was
developed to provide initial guidelines on what type of control to
assign. This matrix is further outlined in the National Cost Impacts
Memorandum, available in the docket. The controls that are available
vary depending on the cleaning machine type, the solvent, and the
percent control that is required. In cases

where more than one control is available, we made a rough starting
assumption regarding the distribution of units. For example, for vapor
cleaning units using PCE, there are two control options available when
the required reduction is between 78 percent to 99 percent--PCE to MC
and a vacuum cleaning machine. In this case, we initially assumed that
approximately 25 percent of the units would choose the PCE to MC option
and that approximately 75 percent of the units would choose the vacuum
cleaning machine option. We assumed that more would choose the vacuum
cleaning machine option because it is more universally applicable. The
solvent switching option will be limited relative to the other options
because TCE and MC will not meet the cleaning requirements for all
cleaning applications. The costs and emission reductions for all units
at all facilities with emissions above the control option limits were
totaled to yield the total national costs and emission reductions.
    Table 6 of this preamble show that control costs increase and
solvent savings increase as the emission limit is set lower. The lower
the limit is established, the greater the number of units that must be
controlled to achieve the limit. Emission reductions are greater when a
lower limit is established, therefore, the solvent savings are greater.
Total annual emission control costs range from a savings of
approximately $6 million/year for the 40,000 kg and the 60,000 kg/year
MC equivalent control options to a cost of $2 million/year for the
6,000 kg/year MC-equivalent control alternative. Capital costs for the
six control alternatives range from approximately $22 million for the
100,000 kg/year MC-equivalent alternative to $193 million for the 6,000
kg/year MC-equivalent alternative. Annualized capital costs range from
$2 million/year for the 100,000 kg/year MC-equivalent control
alternative to $18 million/year for the 6,000 kg/year MC-equivalent
control alternative.
    Incremental costs are negative for the 100,000 kg and the 60,000
kg/year MC-equivalent alternatives at ($1,292)/ton and ($826)/ton,
respectively. Incremental costs for the remaining four alternatives are
positive and range from $16/ton for the 40,000 kg/year MC-equivalent
alternative to $5,549 ton for the 6,000 kg/year MC-equivalent
alternative.
3. What regulatory options is EPA proposing?
    We are proposing two options that achieve an ample margin of
safety. The co-proposed options set facility-wide emission limits that
are specific to reducing MC, TCE, and PCE emissions from halogenated
solvent cleaning facilities and provide an ample margin of safety.
Option 1 limits facility-wide emissions of PCE, TCE and MC to 40,000
kg/yr MC-equivalent. Option 2 limits facility-wide emissions of PCE,
TCE and MC to 25,000 kg/yr MC-equivalent. Our review of the data shows
that these limits can be achieved if facilities improve emission
control through solvent switching (switching from a high risk solvent
to one of lower health risks), reducing solvent use, and investigating
traditionally available options to further reduce emissions. Increased
diligence in controlling lids, installing freeboard chillers,
increasing drying times, installing closed loop systems, and increasing
the freeboard ratio would allow the higher emitting higher risk
facilities to achieve compliance with the proposed standard. The
available information indicates that solvent switching, vapor capture,
maintenance, reduced solvent use, and limiting cleaning runs would be
the primary components of any credits that would offset costs due to
reduced solvent use.
    In selecting these two options, we first determined that adding a
MC-equivalent based emission limit would provide an opportunity for
additional risk reduction. We also determined that these two options
were preferred over the 100,000 and 60,000 kg/yr options because they
reduce the cancer incidence by over one half, they reduce the
population exposed to cancer risks greater than one-in-a-million by
over 5 million people, and both result in net annual cost savings to
the industry.
    We also examined the impacts to small businesses associated with
the alternative emissions limits. Our analysis showed that an emission
limit of 15,000 kg/yr or lower could have an impact on a significant
number of small businesses. To avoid adverse impacts to small
businesses, we concluded that we would not propose an emission limit
option of 15,000 kg/yr or lower.
    Option 1 capital costs are $51 million and total annualized cost
savings of about $6 million. The net annualized cost per unit of
emission reduction is a cost savings of $1,000 per ton of HAP solvent
emissions avoided. Option 2 capital costs are nearly $80 million and
considering solvent savings result in total annualized cost savings of
nearly $5 million. As shown in the cost analysis summarized in Table 6
of this preamble, the net annualized cost of per unit of emission
reduction is a savings of $724 per ton of HAP solvent emissions
avoided.
    In the final rule, we expect to select one of these options, with
appropriate modifications in response to public comments. The emissions
limit would subject the highest emitting facilities to control
requirements that may require switching to a HAP solvent that has a
lower URE, switching to a non-HAP solvent cleaning process, retrofit of
freeboards, addition of vacuum-to-vacuum machines or use of emission
control technology. A description of the two options we are proposing
follows. When estimating the impacts for each of these options, the
CalEPA URE for PCE was used, except where noted. Use of the OPPTS URE
for PCE will change the estimated impacts.
4. Rationale for Option 1
    Under the authority of Section 112(f), we are co-proposing an
emission limit of 40,000 kg/yr (88,000 lbs/yr) MC-equivalent to be
applicable to facilities whose emission of MC, TCE and PCE exceed this
emission cap. Under CalEPA, Option 1 would reduce total HAP emissions
by as much as 5,800 tons/year. Thirty-two percent of those HAP
emissions, about 1,860 tons/year would be PCE, 54 percent, about 3,130
tons/year would be TCE and the remaining 14 percent, about 810 tons/
year would be MC.
    Under this proposed option, we estimate that approximately 90
percent of the people living within 20 km of the halogenated solvent
cleaning facility, about 5.4 million people of the original 6 million
people, would no longer be exposed at risk levels higher than 1-in-a-
million, and the MIR would be reduced from the baseline of between 90
and 200-in-a-million (depending on URE for PCE) to about 20-in-a-
million, representing an 80 to 90 percent reduction in the MIR. The
cancer incidence would be reduced from the baseline of between 0.20 and
0.40 cases per year (depending on URE for PCE) down between 0.08 to
0.17 cases per year, a reduction of about 60 percent.
    We anticipate that as many as 25 percent of the halogenated solvent
cleaning facilities will be affected by a 40,000 kg/year MC-equivalent
emission limit. These facilities emit approximately 87 percent of the
total MC-equivalent source category carcinogenic emissions.
    We estimate that nearly 380 halogenated solvent cleaning machines
may become subject to this option. Facilities would reduce their
emissions by selecting a suitable control option that might include one
or more of the following: (1) Solvent switching from

PCE to MC, PCE to TCE or TCE to MC; (2) installation of vacuum to
vacuum cleaning machines; (3) retrofitting a 1.5 freeboard ratio (FBR);
or, (4) retrofitting of 1.5 FBR, working mode cover (WC), and freeboard
refrigeration device (FRD) control combination. To achieve the emission
limit of 40,000 kg/yr MC-equivalent, nearly 31 percent of the affected
facilities may need to select vacuum to vacuum cleaning machines to
achieve necessary emission reductions. We estimate the annualized
capital costs plus the operation and maintenance (O&M) costs at nearly
$4.4 million for these machines, yet with a solvent savings of nearly
$8.9 million, the total annualized control costs would ultimately save
the industry nearly $4.5 million for this emission control.
    Nearly thirty-eight percent of the affected facilities may select
either of the two retrofitting options for their cleaning machines. We
estimate the annualized capital cost plus the O&M cost at nearly $520
thousand for retrofitting, yet with solvent savings of nearly $1.16
million, the total annualized control costs would ultimately save the
industry nearly $640 thousand for this emission control.
    The remaining 30 percent may select a solvent switching option,
however, it is expected that only 6 percent of facilities may be able
to switch from using PCE to using MC, yet, 17 percent of the facilities
can switch from TCE to MC. We estimate the annualized capital cost plus
O&M costs for solvent switching at nearly $320 thousand for solvent
switching, yet with solvent savings of nearly $1.02 million, the total
annualized control costs would ultimately save the industry nearly $700
thousand for this emission control.
5. Rationale for Option 2
    Under the authority of Section 112(f), we are co-proposing an
emission limit of 25,000 kg/yr (55,000 lbs/yr) MC-equivalent to be
applicable to facilities whose emission of MC, TCE and PCE exceed this
emission cap. Under Option 2, total HAP emissions would be reduced by
6,700 tons/year. Thirty percent, 2,010 tons/year of the HAP emissions
reduced would be PCE, 56 percent, 3,750 tons/year TCE and the remaining
14 percent 940 tons/year would be MC.
    Under this proposed option, we estimate that approximately 97
percent of the people living within 20 km of the halogenated solvent
cleaning facility, about 5.8 million of the original 6 million people,
would no longer be exposed at risk levels higher than 1-in-a-million,
and the MIR would be reduced from the baseline of between 90 and 200-
in-a-million (depending on URE for PCE) to about 10-in-a-million,
representing a 90 to 95 percent reduction in the MIR. The cancer
incidence would be reduced from the baseline of between 0.20 and 0.40
cases per year (depending on URE for PCE) down to between 0.06 and 0.13
cases per year, a reduction of 70 percent.
    We anticipate that as many as 30 percent of the halogenated solvent
cleaning facilities will be affected by a 25,000 kg/year MC-equivalent
emission limit. These facilities emit approximately 92 percent of the
total MC-equivalent source category carcinogenic emissions.
    We estimate that nearly 500 halogenated solvent cleaning machines
may become subject to this option. Facilities would reduce their
emissions by selecting a suitable control option that might include one
or more of the following: (1) Solvent switching from PCE to MC, PCE to
TCE or TCE to MC; (2) installation of vacuum to vacuum cleaning
machines; (3) retrofitting a 1.5 FBR; or, (4) retrofitting of 1.5 FBR,
WC and FRD control combination.
    To achieve the emission limit of 25,000 kg/yr MC-equivalent, nearly
39 percent of the affected facilities may need to select vacuum to
vacuum cleaning machines to achieve necessary emission reductions. We
estimate the annualized capital costs plus O&M costs at nearly $7.1
million for these machines, yet with a solvent savings of nearly $10.6
million, the total annualized control costs would ultimately save the
industry nearly $34.5 million for using the vacuum cleaning machines.
    Nearly 31 percent of the affected facilities may select either of
the two retrofitting options for their cleaning machines. We estimate
the annualized capital cost plus O&M costs at nearly $520 thousand for
retrofitting, yet with solvent savings of nearly $960 thousand, the
total annualized control costs would ultimately save the industry
nearly $430 thousand for this emission control.
    The remaining 31 percent may select a solvent switching options,
however, it is expected that only 6 percent of facilities may be able
to switch from using PCE to using MC and 7 percent may switch from
using PCE to TCE, yet, 17 percent of the facilities can switch from TCE
to MC. We estimate the annualized capital cost plus O&M costs at nearly
$320 thousand for solvent switching, yet with solvent savings of nearly
$1.3 million, the total annualized control costs would ultimately save
the industry nearly $980 thousand for this emission control.
6. Comparison of Option 1 and 2
    The Agency would conclude under this proposal that Option 1 would
be the most effective in reducing risk and maximizing the cost savings
associated with reducing emissions from these operations. This option
would achieve an ample margin of safety by reducing MIR to 20-in-a-
million and reducing cancer incidence to between 0.08 and 0.17 cases
per year. Proposed Option 2 would reduce MIR to 10-in-a-million and
reduce incremental cancer incidence by between 0.02 and 0.04 cancer
cases per year (or 1 to 2 cancer cases every 50 years) at an additional
cost of roughly one million dollars per year and also requires higher
capital investment of almost $29 million dollars over Option 1. Given
the uncertainties associated with these risk estimates and the
relatively small incremental changes in the distribution of risk under
Option 2, we are proposing under Option 1 that it is not necessary to
impose the additional control required by Option 2 to provide an ample
margin of safety to protect public health. The agency seeks comment on
whether to base the final rule on Option 1 or Option 2.

F. What is EPA proposing pursuant to CAA section 112(d)(6)?

    CAA section 112(d)(6) requires EPA to review and revise, as
necessary (taking into account developments in practices, processes,
and control technologies), emission standards promulgated under CAA
section 112 no less often than 8 years. We reviewed available
information about the industry and talked with industry representatives
to investigate available emission control technologies and the
potential for additional emission reductions. Based on our review, we
believe that it is not necessary to revise the GACT standards for cold
batch area sources in this rulemaking. 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). Vacuum-to-vacuum machines, which were undemonstrated at the
time of the development of the NESHAP, are now offered by several
equipment vendors. The use of vacuum-to-vacuum cleaners has increased
as the costs for them have declined. However, due to their batch
design, relatively high cost, and typically small cleaning capacity,
vacuum-to-vacuum cleaning machines are not appropriate for all
applications. Therefore, our investigation did not identify any
significant developments in practices,

processes, or control technologies for halogenated solvent cleaning
since promulgation of the original standards in 1994. Under both
options, we are proposing that these changes to the current halogenated
solvent cleaning NESHAP also satisfy the requirements under our CAA
section 112(d)(6) authority.

G. What is the rationale for the proposed compliance schedule?

    We are also proposing compliance dates for sources subject to the
proposed revised standards pursuant to section 112(i) of the CAA. When
Congress amended the CAA in 1990, it established a new, comprehensive
set of provisions regarding compliance deadlines for sources subject to
emissions standards and work practice requirements that EPA promulgates
under CAA section 112. However, as discussed later in this section of
this preamble, Congress also left in place other provisions in CAA
section 112(f))4) that in certain respects are redundant or conflict
with the new compliance deadline provisions. These provisions also fail
to accommodate the new State-administered air operating permit program
added in Title V of the amended CAA.
    For new sources, CAA section 112(i)(1) requires that after the
effective date of ``any emission standard, limitation, or regulation
under subsection (d), (f) or (h), no person may construct any new major
source or reconstruct any existing major source subject to such
emission standard, regulation or limitation unless the Administrator
(or State with a permit program approved under Title V) determines that
such source, if properly constructed, reconstructed and operated, will
comply with the standard, regulation or limitation.'' CAA section
112(a)(4) defines a ``new source'' as ``a stationary source the
construction or reconstruction of which is commenced after the
Administrator first proposes regulations under this section
establishing an emission standard applicable to such sources.'' Under
CAA sections 112(e)(10) and 112(f)(3), any CAA section 112(d)(6)
emission standards and any residual risk emission standards shall
become effective upon promulgation. This means generally that a new
source that is constructed or reconstructed after this proposed rule is
published must comply with the final standard, when promulgated,
immediately upon the rule's effective date or upon the source's start-
up date, whichever is later.
    There are some exceptions to this general rule. First, CAA section
112(i)(7) provides that a source for which construction or
reconstruction is commenced after the date an emission standard is
proposed pursuant to subsection (d) but before the date a revised
emission standard is proposed under subsection (f) shall not be
required to comply with the revised standard until 10 years after the
date construction or reconstruction commenced. This provision ensures
that new sources that are built in compliance with MACT will not be
forced to undergo modifications to comply with a residual risk rule
unreasonably early.
    In addition, CAA sections 112(i)(2)(A) and (B) provide that a new
source which commences construction or reconstruction after a standard
is proposed, and before the standard is promulgated, shall not be
required to comply with the promulgated standard until 3 years after
the rule's effective date, if the promulgated standard is more
stringent than the proposed standard and the source complies with the
proposed standard during the three-year period immediately after
promulgation. This provision essentially treats such new sources as if
they are existing sources in giving them a consistent amount of time to
convert their operations to comply with the more stringent final rule
after having already been designed and built according to the proposed
rule.
    For existing sources, CAA section 112(i)(3)(A) provides that after
the effective date of ``any emission standard, limitation or regulation
promulgated under this section and applicable to a source, no person
may operate such source in violation of such standard, limitation or
regulation except, in the case of an existing source, the Administrator
shall establish a compliance date or dates which shall provide for
compliance as expeditiously as practicable, but in no event later than
3 years after the effective date of such standard.'' This potential
three year compliance period for existing sources under CAA section
112(i)(3) matches the 3-year compliance period provided for new sources
subject to CAA section 112(d), (f), or (h) standards that are
promulgated to be more stringent than they were proposed, as provided
in CAA sections 112(i)(1) and (2).
    As for new sources, there are exceptions to the general rule for
existing sources under CAA section 112(i)(3), the most relevant being
CAA section 112(i)(3)(B) allowance that EPA or a State Title V
permitting authority may issue a permit granting a source an additional
one year to comply with standards ``under subsection (d)'' if such
additional period is necessary for the installation of controls. As
explained below, EPA now believes that this reference to only
subsection 112(d), rather than to CAA section 112 in general, was
accidental on Congress' part and presents a conflict with the rest of
the statutory scheme Congress enacted in 1990 to govern compliance
deadlines under the amended CAA section 112.
    Even though, in 1990, Congress amended CAA section 112 to include
the comprehensive provisions in subsection 112(i) regarding compliance
deadlines, the enacted CAA also included provisions in CAA section
112(f), leftover from the previous version of the Act, that apply
compliance deadlines for sources subject to residual risk rules. These
deadlines differ in some ways from the provisions of CAA section
112(i). First, CAA section 112(f)(4) provides that no air pollutant to
which a standard ``under this subsection applies may be emitted from
any stationary source in violation of such standard * * *'' For new
sources, this is a redundant provision, since the new provisions added
by Congress in CAA sections 112(i)(1), (2), (3), and (7)--which
explicitly reach standards established under CAA section 112(f)--
already impose this prohibition with respect to new sources and provide
for the allowable exceptions to it. In contrast, for new sources, the
prohibition in CAA section 112(f)(4) provides for no exception for a
new source built shortly before a residual risk standard is proposed,
makes no reference to the new Title V program as an implementation
mechanism, and, where promulgated standards are more stringent than
their proposed versions, makes no effort to align compliance deadlines
for new sources with those that apply for existing sources. From the
plain language of CAA section 112(i), it is clear that Congress
intended in the 1990 amendments to comprehensively address the
compliance deadlines for new sources subject to any standard under
either subsections 112(d), (f), or (h), and to do so in a way that
accommodates both the new Title V program added in 1990 and the fact
that where circumstances justify treating a new source as if it were an
existing source, a substantially longer compliance period than would
otherwise apply is necessary and appropriate. It is equally clear that
the language in CAA section 112(f)(4) fails on all these fronts for new
sources.
    In addition, for existing sources, CAA section 112(f)(4)(A)
provides that a residual risk standard and the prohibition against
emitting HAP in

violation thereof ``shall not apply until 90 days after its effective
date.'' However, CAA section 112(f)(4)(B) states that EPA ``may grant a
waiver permitting such source a period up to 2 years after the
effective date of a standard to comply with the standard if the
Administrator finds that such period is necessary for the installation
of controls and that steps will be taken during the period of the
waiver to assure that the health of persons will be protected from
imminent endangerment.'' These provisions are at odds with the rest of
the statutory scheme governing compliance deadlines for CAA section 112
rules in several respects. First, the 90-day compliance deadline for
existing sources in CAA section 112(f)(4)(A) directly conflicts with
the up-to-3-year deadline in CAA section 112(i)(3)(A) allowed for
existing sources subject to ``any'' rule under CAA section 112. Second,
the CAA section 112(f)(4)(A) deadline results in providing a shorter
deadline for ordinary existing sources to comply with residual risk
standards than would apply under CAA section 112(i)(2) to new sources
that are built after a residual risk standard is proposed but a more
stringent version is promulgated. Third, while both CAA section
112(i)(1), for new sources subject to any CAA section 112(d), (f), or
(h) standard, and CAA section 112(i)(3), for existing sources subject
to any CAA section 112(d) standard, refer to and rely upon the new
Title V permit program added in 1990 and explicitly provide for State
permitting authorities to make relevant decisions regarding compliance
and the need for any compliance extensions, CAA section 112(f)(4)(B)
still reflects the pre-1990 statutory scheme in which only the
Administrator is referred to as a decision-making entity,
notwithstanding the fact that even residual risk standards under CAA
section 112(f) are likely to be delegated to States for their
implementation, and will be reflected in sources' Title V permits and
need to rely upon the Title V permit process for memorializing any
compliance extensions for those standards.
    While we appreciate the fact that CAA section 112(i)(3)(B) refers
specifically only to standards under subsection 112(d), which some
might argue means that subsection 112(i)(3), in general, applies only
to existing sources subject to CAA section 112(d) standards, we believe
that Congress inadvertently limited its scope and created a statutory
conflict in need of our resolution. Notwithstanding the language of
subparagraph (B), CAA section 112(i)(3)(A) by its terms applies to
``any'' standard promulgated under CAA section 112, which includes
those under CAA section 112(f), in allowing up to a three year
compliance period for existing sources. Moreover, Congress clearly
intended that the CAA section 112(i) provisions, applicable to new
sources to govern compliance deadlines under CAA section 112(f) rules,
notwithstanding the language of CAA section 112(f)(4). This is because
CAA sections 112(i)(1) and (2) explicitly reaches the standards under
CAA section 112(f). To read CAA section 112(i)(3)(B) literally as
reaching only CAA section 112(d) standards, with CAA section
112(f)(4)(B) reaching CAA section 112(f) standards, leaves the question
as to whether there can be compliance extensions for CAA section 112(h)
standards completely unaddressed by the statute, even though it may in
fact be necessary in complying with a CAA section 112(h) work practice
standard to install equipment or controls. A narrow reading of the
scope of CAA section 112(i)(3) also ignores the fact that in many
cases, including that of this proposed rule, the governing statutory
authority will be both CAA section 112(f)(2) and CAA section
112(d)(6)--the only reasonable way to avoid a conflict in provisions
controlling compliance deadlines for existing sources in these
situations is to read the more specific and comprehensive set of
provisions, those of CAA section 112(i), as governing both aspects of
the regulation.
    Nothing in the legislative history suggests that Congress knowingly
intended to enact separate schemes for compliance deadlines for
residual risk standards and all other standards adopted under CAA
section 112. Rather, comparing the competing Senate and House Bills
shows that each bill contained its own general and/or specific versions
of compliance deadline provisions, and that when the bills were
reconciled in conference the two schemes were both accidentally
enacted, without fully modifying the various compliance deadline
provisions in accord with the modifications otherwise made to the CAA
section 112 amendments in conference.
    Nevertheless, we are proposing a compliance deadline of 2 years for
existing sources of halogenated emissions from halogenated solvent
cleaning machines. We believe this proposed compliance deadline is both
reasonable and realistic for any affected facility that has to plan
their control strategy, purchase and install the control device(s), and
bring the control device online.

IV. Solicitation of Public Comments

A. Introduction and General Solicitation

    We request comments on all aspects of the proposed amendments. All
significant comments received during the public comment period will be
considered in the development and selection of the final rulemaking.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review

    Under Executive Order (EO) 12866 (58 FR 51735, October 4, 1993),
this action is a ``significant regulatory action.'' An economic impact
analysis was performed to estimate changes in price and output for
affected halogenated solvent cleaning sources using the annual
compliance costs estimated for proposed Options 1 and 2. Analysis for
options 1 and 2 indicate an annual cost savings due to the reduction in
solvent demand. Option 2 would result in higher cost savings of the
options presented. For more information, refer to the economic impact
analysis report that is in the public docket for this rule.
    Pursuant to the terms of EO 12866, this proposed rule has been
determined to be a ``significant regulatory action'' because it raises
novel legal and policy issues. Accordingly, EPA has submitted this
action to OMB for review under EO 12866 and any changes made in
response to OMB recommendations have been documented in the docket for
this action.

B. Paperwork Reduction Act

    This action does not impose any new information collection burden.
We are proposing no additional requirements in this action to direct
owners and operators to generate, maintain, or disclose or provide
information to or for a Federal agency. However, the Office of
Management and Budget (OMB) has previously approved the information
collection requirements contained in the existing regulations 40 CFR
Part 63, Subpart T (1994 national emission standards for Halogenated
Solvent Cleaning) under the provisions of the Paperwork Reduction Act,
44 U.S.C. 3501 et seq. and has assigned OMB control number (2060-0273),
EPA ICR number 1652.05. A copy of the OMB approved Information
Collection Request (ICR) may be obtained from Susan Auby, Collection
Strategies Division; U. S. Environmental Protection Agency (2822T);
1200 Pennsylvania Ave., NW., Washington, DC 20460 or by calling (202)
566-1672.

    Burden means the total time, effort, or financial resources
expended by persons to generate, maintain, retain, or disclose or
provide information to or for a Federal Agency. This includes the time
needed to review instructions; develop, acquire, install, and utilize
technology and systems for the purposes of collecting, validating, and
verifying information, processing and maintaining information, and
disclosing and providing information; adjust the existing ways to
comply with any previously applicable instructions and requirements;
train personnel to be able to respond to a collection of information;
search data sources; complete and review the collection of information;
and transmit or otherwise disclose the information.
    An agency may not conduct or sponsor, and a person is not required
to respond to, a collection of information unless it displays a
currently valid OMB control number. The OMB control numbers for EPA's
regulations in 40 CFR part 63 are listed in 40 CFR part 9.

C. Regulatory Flexibility Act

    The Regulatory Flexibility Act (RFA) generally requires an agency
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the agency certifies that the
rule will not have a significant economic impact on a substantial