# Draft Determination of Adequacy of Section 112 Authorities And Draft Determination of Need for Additional Standards

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## Record

- **Collection:** Federal Register
- **Document type:** Notice
- **Published:** July 7, 1997
- **Citation:** 62 FR 36436

## Text

ENVIRONMENTAL PROTECTION AGENCY

[FRL-58536-3; Docket No. A-97-21]
RIN 2060-AH49

Draft Determination of Adequacy of Section 112 Authorities And
Draft Determination of Need for Additional Standards

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice of draft determinations.

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SUMMARY: Today's notice provides, for public comment, the EPA's draft
determinations that the legal authorities and mandates provided by
section 112 of the Clean Air Act (CAA) are adequate to prevent serious,
adverse, public health effects and serious or widespread environmental
effects associated with atmospheric deposition of hazardous air
pollutants to the Great Waters. Today's notice also provides EPA's
draft determination that, at this time, further emission standards or
control measures under section 112, beyond those otherwise authorized
by section 112, are not necessary and appropriate to prevent such
effects. These actions are being taken pursuant to section 112(m)(6) of
the CAA, as amended in 1990, and a consent decree entered in Sierra
Club v. Browner, Civ. No. 96-1680. Final determinations are required
under the consent decree to be made by March 15, 1998.

DATES: Written comments must be submitted by August 6, 1997.

ADDRESSES: Commenters must send an original and two copies of their
comments, referencing docket number A-97-21, to the Air Docket, U.S.
Environmental Protection Agency, 401 M Street, SW, Washington, DC
20460.
Comments and data may also be submitted electronically by following
the instructions under SUPPLEMENTARY INFORMATION of this document. No
Confidential Business Information (CBI) should be submitted through e-
mail.

FOR FURTHER INFORMATION CONTACT: Dianne Byrne, Office of Air Quality
Planning and Standards (MD-15), U.S. Environmental Protection Agency,
Research Triangle Park, North Carolina 27711, telephone number (919)
541-5342.

SUPPLEMENTARY INFORMATION:

Electronic Availability

The official record for this notice, as well as the public version,
has been established for this notice under docket number A-97-21
(including comments and data submitted electronically as described
below). A public version of this record, including printed, paper
versions of electronic comments, which do not include any information
claimed as CBI, is available for inspection from 8 a.m. to 4 p.m.,
Monday through Friday, excluding legal holidays. The official record is
located at the address in ADDRESSES at the beginning of this document.
Electronic comments can be sent directly to EPA at A-and-R-
D[email protected]. Electronic comments must be submitted as an
ASCII file avoiding the use of special characters and any form of
encryption. Comments and data will also be accepted on disks in Word
Perfect in 5.1 file format or ASCII file format. All comments and data
in electronic form must be identified by the docket number (A-97-21).
Electronic comments on this draft notice may be filed online at many
Federal Depository Libraries.
The information in this notice is organized as follows:

I. Background
II. Introduction
A. Statutory Requirements for Great Waters Program
B. Scope of Analysis
III. Statutory Analysis--Other Provisions Relative to section 112(m)
Mandate
A. Definition of Major Source
B. Definition of Adverse Environmental Effect
C. Listing of Pollutants
D. Listing of Sources
E. Regulations to Control Emissions of Pollutants
1. MACT and GACT Standards
2. Residual Risk Standards
F. Urban Area Source Program
G. Studies and Reports to Congress
1. Mercury
2. Electric Utilities
H. Solid Waste Incineration Units
IV. Determination of Adequacy and No Need for Further Regulations

I. Background

Pursuant to section 112(m)(6) of the CAA, EPA is submitting for
public comment a draft determination that the legal authorities and
mandates provided by section 112 of the CAA are adequate to prevent
serious, adverse, public health effects and serious or widespread
environmental effects associated with atmospheric deposition of
hazardous air pollutants (HAP) to the Great Waters. The EPA is also
submitting for public comment its draft determination that further
emissions standards or control measures under section 112(m)(6), beyond
those otherwise authorized or required by section 112, are not at this
time necessary or appropriate to prevent such effects. The bases for
these draft determinations are discussed in today's notice and are
briefly summarized below.
Section 112(m)(6) of the CAA requires that EPA determine whether
adequate authority exists within the provisions of section 112, other
than subsection (m)(6) to prevent serious, adverse, effects to public
health and serious or widespread environmental effects associated with
atmospheric deposition of HAP to the Great Waters. In conducting this
assessment, EPA reviewed the authorities granted by section 112, as
they may function to reduce adverse effects caused by deposition of HAP
to the Great Waters. It should be emphasized that this determination
pertains to the authority within the CAA to take actions as appropriate
to address the enumerated effects; it does not pertain to the efficacy
of prior or future actions. In addition, the scope of this
determination is focused on the authority within section 112 to address
those pollutants and sources that can be regulated under that section's
authority. As such, pollutants that are not listed as HAP, pursuant to
section 112(b), and source categories that could not be listed pursuant
to section 112(b) are not included within the scope of this
determination. While not part of this determination, it may be useful
to note that some unlisted pollutants that are pollutants of concern to
the Great Waters are regulated by other sections of the CAA (such as
nitrogen oxides which are regulated pursuant to sections 108, 109, 202,
and section 407). Similarly, source categories that are outside the
scope of section 112 can be regulated under other provisions of the CAA
(such as mobile sources regulated pursuant to section 202). Emissions
of the Great Waters' pollutants of concern that are addressed by other
statutes (e.g., wastewater discharges addressed by the Clean Water Act)
are also not within the scope of this adequacy determination.
Section 112 establishes a statutory scheme by which EPA is to
identify HAP which may cause or contribute to adverse effects to public
health or the environment, develop performance standards for the
control of emissions from stationary sources of such HAP (in addition
to the HAP listed by Congress in the CAA), and adjust these control
requirements as needed to address any remaining unacceptable risk that
may be present after sources have complied with the emission standards.
The types of adverse environmental effects to be prevented are defined
in the CAA and are broad in scope. An adverse environmental effect is
defined by section 112(a)(7) as ``any significant and widespread
adverse effect, which may reasonably be anticipated, to wildlife,

[[Page 36437]]

aquatic life, or other natural resources, including adverse impacts on
populations of endangered or threatened species or significant
degradation of environmental quality over broad areas.''
Authorities provided by other provisions of section 112 that may be
particularly relevant to the Great Waters' pollutants and sources are
briefly summarized below. Section 112 authorizes EPA to:

--Identify and list any air pollutant that may cause adverse effects
due to atmospheric deposition (section 112(b)).
--Identify and list any stationary source category that emits
pollutants with the potential to cause adverse effects (section
112(c)).
--Establish a lesser quantity (e.g., below 10 tons per year for a
single pollutant) emission rate based on several factors, including
persistence and potential to bioaccumulate. Such emission rate, once
established, would replace the 10 ton per year rate, per pollutant,
that is otherwise used to define a major source (section 112(a)(1)).
--Establish test methods and analytic procedures for monitoring and
measuring emissions, ambient concentrations, deposition, and
bioaccumulation of HAP (section 112(b)(5)).
--List sources of 7 specific HAP to assure at least 90 percent of
emissions of each pollutant are subject to national emission standards
(section 112(c)(6)). These pollutants are of particular concern for the
Great Waters.
--Promulgate performance standards (section 112(d)) for major sources
and listed area sources. These standards are to reflect the maximum
degree of emission reduction that is achievable, taking into
consideration the cost of achieving such reduction, non-air quality
health and environmental impacts, and energy requirements. In addition,
these standards are to apply pollution prevention measures, processes,
methods, systems or techniques which reduce the volume of or eliminate
emissions through process changes, substitution of materials, enclosure
of systems or processes, and other measures.
--Require additional controls, as necessary to provide an ample margin
of safety to protect public health or to prevent an adverse
environmental effect. Authority to take action, as needed, to help
prevent the effects identified under section 112(m)(6) is provided by
the ``residual risk'' provision (section 112(f)).
--Complete and transmit to Congress two studies that are especially
relevant to the Great Waters program. The first is a study of mercury
emissions from electric utilities, municipal waste combustors, and
other sources, including smaller (i.e., area) sources. When the study
becomes final, the results will be helpful in prioritizing mercury
reduction strategies. The second study addresses the hazards to public
health expected to occur as a result of HAP emissions from electric
utilities. Section 112(n)(1)(A) further requires that EPA determine,
based on the results its study, whether regulations to reduce utility
emissions are warranted. This regulatory determination has not yet been
made (section 112(n)(1)).

Based on its analysis of these section 112 provisions, and on
current knowledge of emission sources, atmospheric transport and
deposition, and bioaccumulation, EPA believes that section 112
authority is adequate to prevent serious adverse effects to public
health and serious or widespread environmental effects associated with
the deposition of HAP to Great Waters. If the other authorities of
section 112 are found inadequate, section 112(m)(6) of the CAA provides
additional authority to EPA to adopt further emission standards or
other control measures not otherwise mandated or authorized by section
112, if necessary and appropriate, to fully comply with the protective
mandate of the Great Waters provisions. Since EPA believes that the
authorities in section 112 are adequate to prevent the enumerated
effects, EPA believes that it would not be appropriate, at this time,
to promulgate further emission standards or other control measures
under section 112(m)(6) to prevent such effects beyond those already
authorized or required by section 112. In making these draft
determinations, EPA is not determining that air deposition of HAP does
not currently cause or contribute to adverse effects to the public
health or the environment.

II. Introduction

There are three important prerequisites to EPA's ability to
identify the need for, and to develop, appropriate actions to address
adverse health and environmental effects associated with atmospheric
deposition of HAP. First, EPA must have adequate data and methods
(e.g., air emissions inventories, ambient and deposition sampling and
analysis techniques, and atmospheric fate and transport models) with
which to collect and analyze relevant information. Additionally, there
must be scientific support for the establishment of appropriate health
thresholds, dose-response relationships and effects mechanisms.
This information must be sufficient to support scientific and
policy judgments about those effects that should be considered
``serious adverse,'' in the case of human health, and ``serious or
widespread,'' in the case of environmental effects. Finally, the Agency
must have adequate legal authority to adopt regulations which can
effectively reduce the emissions of the pollutants of concern in order
to prevent such effects.
Much of the effort to evaluate the extent to which the first two
prerequisites (technical and science) have been met is summarized in
the first and second Reports to Congress, and EPA expects to continue
significant efforts to develop and improve our understanding of the
scientific and technical issues. Today's notice discusses the third
prerequisite to effective actions, that is, the adequacy of legal
authorities provided by section 112 to prevent the effects specified in
section 112(m)(6), and announces EPA's draft adequacy determination
under that subsection. In addition, today's notice announces EPA's
draft determination regarding whether additional emissions standards or
control measures under section 112, beyond those otherwise authorized
or required by section 112, are at this time necessary and appropriate
to prevent such effects.

A. Statutory Requirements for Great Waters Program

Section 112(m) of the CAA, as amended in 1990, 42 U.S.C. 7401 et
seq. establishes the Great Waters program under which EPA has ongoing
responsibilities to identify and assess the extent of atmospheric
deposition of HAP to the Great Lakes, Chesapeake Bay, Lake Champlain,
and coastal waters (Great Waters, (42 U.S.C. 7412(m)). As part of this
program, EPA is to monitor for atmospheric deposition of HAP in the
Great Waters, investigate the sources of HAP deposition, research the
relative contribution of atmospheric pollutants to total loadings in
the Great Waters, evaluate adverse effects to public health or the
environment caused by HAP deposition, assess the contribution of HAP
deposition to violations of water quality or drinking water standards,
and sample for HAP in

[[Page 36438]]

biota, fish, and wildlife of the Great Waters, (42 U.S.C. 7412(m)(1)
(A)-(E)).1
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\1\ 42 U.S.C. 7412(m)(1) provides:
The Administrator, in cooperation with the Under Secretary of
Commerce for Oceans and Atmosphere, shall conduct a program to
identify and assess the extent of atmospheric deposition of
hazardous air pollutants (and in the discretion of the
Administrator, other air pollutants) to the Great Lakes, the
Chesapeake Bay, Lake Champlain and coastal waters. As part of such
program, the Administrator shall--
(A) monitor the Great Lakes, the Chesapeake Bay, Lake Champlain
and coastal waters, including monitoring of the Great Lakes through
the monitoring network established pursuant to paragraph (2) of this
subsection and designing and deploying an atmospheric monitoring
network for coastal waters pursuant to paragraph (4);
(B) investigate the sources and deposition rates of atmospheric
deposition of air pollutants (and their atmospheric transformation
precursors);
(C) conduct research to develop and improve monitoring methods
and to determine the relative contribution of atmospheric pollutants
to total pollution loadings to the Great Lakes, the Chesapeake Bay,
Lake Champlain, and coastal waters;
(D) evaluate any adverse effects to public health or the
environment caused by such deposition (including effects resulting
from indirect exposure pathways) and assess the contribution of such
deposition to violations of water quality standards established
pursuant to the Federal Water Pollution Control Act [33 U.S.C.A.
1251 et seq.] and drinking water standards established pursuant to
the Safe Drinking Water Act [42 U.S.C.A. 300f et seq.]; and
(E) sample for such pollutants in biota, fish, and wildlife of
the Great Lakes, the Chesapeake Bay, Lake Champlain and coastal
waters and characterize the sources of such pollutants.
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In addition, EPA is to provide periodic Reports to Congress
describing the results of any monitoring, studies, and investigations
conducted under the Great Waters program, addressing the same issues as
mentioned above, and describing any revisions to the requirements,
standards and limitations under the CAA or other Federal laws that are
necessary to protect the public health and environment from atmospheric
deposition (42 U.S.C. 7412(m)(5)).2 The Agency's
implementation of the Great Waters program to date is discussed in the
first two Reports to Congress issued under section 112(m)(5):
``Deposition of Air Pollutants to the Great Waters: First Report to
Congress'', EPA-453/R-93-055 (May 1994); and ``Deposition of Air
Pollutants to the Great Waters: Second Report to Congress'', EPA-453/R-
97-011 (June 1997). Copies of these reports can be obtained, as
supplies permit, from the Library Services Offices (MD-35), U.S.
Environmental Protection Agency, Research Triangle Park, North Carolina
27711, or, for a nominal fee, from the National Technical Information
Service, 5285 Port Royal Road, Springfield, Virginia 22161, phone: 1-
800-553-NTIS or 703-487-4650.
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\2\ 42 U.S.C. 7412(m)(5) provides:
Within 3 years of November 15, 1990, and biennially thereafter,
the Administrator, in cooperation with the Under Secretary of
Commerce for Oceans and Atmosphere, shall submit to the Congress a
report on the results of any monitoring, studies, and investigations
conducted pursuant to this subsection. Such report shall include, at
a minimum, an assessment of--
(A) the contribution of atmospheric deposition to pollution
loadings in the Great Lakes, the Chesapeake Bay, Lake Champlain and
coastal waters;
(B) the environmental and public health effects of any pollution
which is attributable to atmospheric deposition to the Great Lakes,
the Chesapeake Bay, Lake Champlain and coastal waters;
(C) the source or sources of any pollution to the Great lakes,
the Chesapeake Bay, Lake Champlain and costal waters which is
attributable to atmospheric deposition;
(D) whether pollution loadings in the Great lakes, the
Chesapeake Bay, Lake Champlain or coastal waters cause or contribute
to exceedances of drinking water standards pursuant to the Safe
Drinking Water Act [42 U.S.C.A. 300f et seq.] or water quality
standards pursuant to the Federal Water Pollution Control Act [33
U.S.C. 1251 et seq.] or, with respect to the Great lakes,
exceedances of the specific objectives of the Great Lakes Water
Quality Agreement; and
(E) a description of any revisions of the requirements,
standards, and limitations pursuant to this chapter and other
applicable Federal laws as necessary to assure protection of human
health and the environment.
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Finally, section 112(m)(6) requires that the Administrator
determine whether the other provisions of section 112 are adequate to
prevent serious, adverse effects to public health and serious or
widespread environmental effects, including such effects resulting from
indirect exposure pathways, associated with atmospheric deposition to
the Great Waters of HAP (and their atmospheric transformation products,
(42 U.S.C. 7412(m)(6)).3 In making this determination, EPA
is to take into consideration the tendency of HAP to bioaccumulate. If
EPA determines that the other provisions of section 112 are not
adequate, section 112(m)(6) provides that EPA must then promulgate, in
accordance with section 112, such further emission standards or control
measures as may be necessary and appropriate to prevent such effects,
including effects due to bioaccumulation and indirect exposure
pathways. Id. As an initial matter, EPA interprets this latter mandate
to be a requirement to determine, in the first instance, whether
additional controls are necessary and appropriate, rather than as an
absolute requirement to promulgate some additional controls. (See,
e.g., Environmental Defense Fund v. Thomas, 870 F.2d 892, 898-900 (2nd
Cir. 1989) (While district court did not have jurisdiction to compel
the Administrator to revise the national ambient air quality standards
(NAAQS), it did have jurisdiction to compel EPA to take some formal
action either revising the NAAQS or declining to revise them)).
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\3\ 42 U.S.C. 7412(m)(6) provides:
As part of the report to Congress, the Administrator shall
determine whether the other provisions of this section are adequate
to prevent serious adverse effects to public health and serious or
widespread environmental effects, including such effects resulting
from indirect exposure pathways, associated with atmospheric
deposition to the Great Lakes, the Chesapeake Bay, Lake Champlain
and coastal waters of hazardous air pollutants (and their
transformation products). The Administrator shall take into
consideration the tendency of such pollutants to bioaccumulate.
Within 5 years after November 15, 1990, the Administrator shall,
based on such report and determination, promulgate, in accordance
with this section, such further emission standards or control
measures as may be necessary and appropriate to prevent such
effects, including effects due to bioaccumulation and indirect
exposure pathways. Any requirements promulgated pursuant to this
paragraph with respect to coastal waters shall only apply to the
coastal waters of the States which are subject to section 7627(a) of
this title.
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B. Scope of Analysis

In reviewing the language of section 112(m)(6), it is significant
to note the CAA's specific reference to the ``other provisions'' of
section 112 in describing EPA's duty to assess its ability to prevent
the specified effects. This reference to the statutory authorities is
in contrast to a consideration of particular regulatory actions that
might be taken or have already been taken under those provisions, or of
their individual effectiveness. The EPA views this language as calling
for an analysis of the adequacy of the regulatory authorities and
mandates provided by section 112, rather than of specific actions which
might be taken pursuant to this section. In other words, EPA must
determine whether the authorities provided by these provisions can
adequately prevent the enumerated health and environmental effects. In
the event that EPA determines that they cannot, the CAA further
provides limited authority to adopt additional rules not specifically
mandated or authorized by the other provisions of section 112 as needed
to fully comply with section 112(m)(6)'s protective mandate. This
authority is limited by its terms to developing rules ``in accordance
with'' section 112; EPA may not act, pursuant to section 112(m)(6),
inconsistently with the requirements of, or outside the scope of,
section 112. This means that any additional regulations promulgated
pursuant to section 112(m)(6) could apply only to stationary sources of
HAP.
As noted above, EPA does not interpret this language as calling for
an analysis of the adequacy of specific rules or actions which have
been, or will be, taken pursuant to the provisions of section 112. That
is, based on the statutory language itself, for the

[[Page 36439]]

purposes of conducting the required analysis, EPA must presume that the
provisions will be implemented in ways which fully comply with the
substantive requirements of the appropriate subsections of section 112
and not speculate about what actual degree of emissions control results
from a specific rule adopted in accordance with section 112. The EPA's
interpretation of the scope of this analysis is supported by the dates
by which Congress anticipated that this determination and any further
regulations would be adopted, compared to the deadlines imposed under
the Act for full implementation of section 112. Section 112(m)(6)
provides that EPA was to make the determination in the Report to
Congress required by section 112(m)(5). The first Report to Congress
was due on November 15, 1993. The EPA was then required to promulgate
additional regulations, if any, based on the report and determination
by November 15, 1995. However, many of the deadlines for other actions
under section 112 do not fall until much later. By requiring that EPA
complete the process of making this determination and adopting further
standards or control measures within 5 years after November 15, 1990,
EPA presumes Congress knew that a large number of mandated emission
standards, programs, and regulations under section 112 would either not
yet be commenced, or would still be in the early stages of development.
Moreover, even those section 112 controls that had already been
promulgated would not yet have demonstrated either success or failure
at preventing adverse effects to the public health and environment.
Consequently, Congress could not have expected that EPA, at the time
this determination was due, would have sufficient information with
which to judge the actual scientific or technical adequacy of those
recently adopted or future actions or regulations to achieve specific
degrees of protection. Indeed, section 112(c)(6), which requires that
EPA identify the sources of seven specific pollutants which are of
primary concern for the Great Waters, requires only an identification
and listing of sources of those pollutants as of November 15, 1995, the
same date by which EPA must determine whether additional regulations
are necessary and appropriate. Standards to subject these sources to
regulations are not required under section 112(c)(6) to be established
until 5 years thereafter.
While on the surface there might appear to be some conflict between
the section 112(c)(6) and 112(m)(6) deadlines for regulatory action,
EPA believes this tension is reconciled by the Agency's interpretation
of its section 112(m)(6) duty to be to determine adequacy based solely
on an a priori statutory analysis; if after review of the section 112
authorities, EPA concludes that they are inadequate to prevent the
enumerated public health or environmental effects, EPA is required to
establish further regulations based partly on the conclusion that those
other authorities, when eventually implemented, cannot possibly prevent
those effects. In other words, EPA is required under section 112(m)(6)
to plug any gaps it identifies early. But, if the Agency concludes that
section 112 is adequate, the section 112(m)(6) ``duty'' to establish
further regulations is not triggered, and the ``conflict'' with other
provisions' deadlines for regulatory actions becomes moot.
One question that EPA must resolve in making its determination
under section 112(m)(6) concerns the sources of pollutants which are
transported through the atmosphere and the extent to which EPA's
determination must encompass all such sources. This issue is
potentially significant because available information indicates that,
in addition to domestic stationary sources of HAP emissions which may
be subjected to regulation under section 112, atmospheric deposition of
some HAP partially results from mobile source emissions, as well as
transport of emissions from foreign sources. Also, some HAP, which were
historically introduced to the environment by human activities, are
continually being recycled in the environment. That is, pollutants such
as PCBs, certain pesticides, and, to some extent, mercury, can
revolatilize from soils and waterbodies into the air, where they can be
transported downwind to new locations and redeposited, revolatilizing
again back into the air from these new locations and transporting
further downwind.
Nothing in the language of section 112(m)(6) suggests that the
Agency must consider these other sources in determining whether the
provisions of section 112 are adequate to prevent the adverse health or
environmental effects. That is, the statutory language does not extend
the scope of EPA's analysis to encompass impacts from HAP emissions
from sources that could not conceivably be subjected to section 112
regulation. Section 112(m)(6) goes on to provide that if EPA has
determined the other provisions of section 112 are inadequate, EPA must
promulgate additional necessary and appropriate emission standards or
other control measures ``in accordance with this section,'' i.e., in
accordance with section 112 (42 U.S.C. 7412(m)(6)). Section 112 does
not confer authority on the Agency to regulate mobile sources,
nondomestic sources of HAP emission, or contaminated sediments.
Instead, section 112, and the potential remedy to address an
``inadequacy'' determination under section 112(m)(6), is restricted in
application to stationary sources of HAP within the possible regulatory
reach of section 112. Moreover, EPA believes that Congress, in enacting
the section 112(m)(6) duty to evaluate the adequacy of section 112,
clearly understood that section 112, and the section 112 remedy
contained in section 112(m)(6), could only extend to stationary sources
already within the scope of the section. This is because it would have
been unnecessary to ask whether section 112 is adequate to control
sources that are clearly beyond its scope, such as mobile sources. For
these reasons, it is EPA's view that the scope of the section 112(m)(6)
determination should be limited to consideration of the adequacy of
section 112 provisions to prevent the enumerated adverse effects
associated with HAP emissions from sources which are within the scope
of EPA's authority to regulate under section 112. It is important to
note that it does not follow from this interpretation that in order to
determine that there are, or to address, adverse effects to public
health or serious or widespread effects to the environment under
section 112, EPA must consider only the contributions from domestic
stationary sources subject to regulation under section 112.

III. Statutory Analysis--Other Provisions Relative to Section 112(m)
Mandate

Among other things, section 112 establishes a statutory scheme
through which EPA is to identify HAP which present or may present a
threat of adverse human health effects or adverse environmental
effects, develop standards for the control of emissions from major
stationary and area sources of such HAP (and the HAP listed by Congress
in the CAA), and adjust these emission control requirements to address
any remaining unacceptable risk which may be present once sources have
complied with the emission standards. The following sections discuss
these provisions in further detail, describing the extent to which they
authorize or enable actions to prevent serious adverse public health
effects and serious or widespread environmental effects associated with
atmospheric HAP deposition to the Great Waters, as described in section
112(m)(6).

[[Page 36440]]

A. Definition of Major Source

Section 112(a) sets forth several definitions that partly define
the scope of EPA's regulatory authority under section 112. The
definition of ``major source'' at section 112(a)(1), for example,
functions in part to establish which types of stationary sources must
be subjected to the most stringent controls. In addition, however, it
provides authority to include more sources within the definition, and
thus allows EPA to subject additional sources to more stringent
controls than is otherwise required under section 112 (42 U.S.C.
7412(a)(1)).\4\ While a major source is initially defined to mean any
stationary source or group of stationary sources located within a
contiguous area and under common control that emits or has the
potential to emit, considering controls, in the aggregate, 10 tons per
year of any HAP or 25 tons per year of any combination of HAP, EPA may
establish a lesser quantity for a major source based on the potency of
the air pollutant, persistence, potential for bioaccumulation, other
characteristics of the air pollutant, or other relevant factors.
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\4\ 42 U.S.C. 7412(a)(1) provides:
The term ``major source'' means any stationary source or group
stationary sources located within a contiguous area and under common
control that emits or has the potential to emit considering
controls, in the aggregate, 10 tons per year or more of any
hazardous air pollutant or 25 tons per year or more of any
combination of hazardous air pollutants. The Administrator may
establish a lesser quantity, or in the case of radionuclides
different criteria, for a major source than that specified in the
previous sentence, on the basis of the potency of the air pollutant,
persistence, potential for bioaccumulation, other characteristics of
the air pollutant, or other relevant factors.
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Section 112(m)(6) requires EPA to consider the tendency of HAP to
bioaccumulate when making its determination as to the adequacy of
section 112 (42 U.S.C. 7412(m)(6)). Since section 112(a)(1) allows EPA
to base lesser quantity emission rates for defining major sources on
bioaccumulation and other relevant factors, the authority in section
112(a)(1) can be used, in concert with other provisions of section 112
as discussed below, to impose controls that could help prevent the
enumerated effects associated with atmospheric deposition of HAP to the
Great Waters.

B. Definition of Adverse Environmental Effect

Section 112(a)(7) defines ``adverse environmental effect'' to mean
``any significant and widespread adverse effect, which may be
reasonably anticipated, to wildlife, aquatic life, or other natural
resources, including adverse impacts on populations of endangered or
threatened species or significant degradation of environmental quality
over broad areas'' (42 U.S.C. 7412(a)(7)). The EPA interprets the scope
of this term to apply as broadly as the language included in section
112(m)(6) requiring EPA to prevent serious or widespread environmental
effects associated with atmospheric deposition to the Great Waters of
HAP and their transformation products. The EPA notes that the language
of section 112(a)(7) and 112(m)(6) is different: where the former
refers to ``significant and widespread adverse effect,'' the latter
refers to ``serious or widespread environmental effects.''
The legislative history does not provide further clarification of
the reasons for the differences in the terminology used in these two
provisions or otherwise suggest that Congress intended for the two
phrases to have different meanings. Rather, references to the House
Amendments that became section 112(m)(6) indicate that the sponsors
understood the language in the Amendments to have the same meaning as
that used elsewhere in section 112 to describe ``adverse''
environmental effects. (See, e.g., remarks of Mr. Levine, House Debate
5-21-90, reprinted in A Legislative History of the Clean Air Act
Amendments of 1990, at 2633; Remarks of Mr. Bilirakis, House Debate 5-
23-90, id., at 2941; Remarks of Mr. Lagomarsino, House Debate 5-23-90,
id., at 2946; Remarks of Mr. Levine, House Debate 5-23-90, id., at
2938.) The EPA believes that these differences do not impose materially
different standards, and that for purposes of the section 112(m)(6)
determination, the standard imposed under section 112(a)(7) is
substantially the same as that in section 112(m)(6). This is because
EPA interprets section 112(m)(6) as directing EPA to assure that only
``adverse'' environmental effects from HAP deposition are prevented,
rather than effects that are not ``adverse,'' if any exist. In this
context, EPA believes that the differing language in the two
subsections functions interchangeably. (See, e.g., De Sylva v.
Ballentine, 351 U.S. 570 (1956) (``the word `or' is often used as a
careless substitute for the word `and,' that is, it is often used in
phrases where `and' would express greater clarity''); See also, U.S. v.
Moore, 613 F.2d 1029 (D.C. Cir. 1979); U.S. v. 1973 One Rol ls Royce,
43 F.3d 794 (3rd Cir. 1994); Kelly v. Wauconda Park Dist., 801 F.2d 269
(7th Cir. 1986); U.S. v. Smeathers, 884 F.2d 363 (8th Cir. 1989). While
the use of different terminology in ections 112(a)(7) and 112(m)(6)
does raise some ambiguity regarding Congress' intent, EPA believes that
the most reasonable way to resolve this ambiguity is to read the
slightly different language in section 112(m)(6) consistently with how
Congress defined environmental effects of concern for 11 other purposes
under section 112. (See Chevron U.S.A., Inc. v. NRDC, 467 U.S. 837
(1984).) Otherwise, under a literal reading, Congress might be viewed
as having charged EPA with the duty to prevent environmental effects
which by definition under section 112 are not ``adverse.'' The EPA does
not believe such a reading would make sense, either as a matter of
statutory interpretation or as a matter of environmental policy.
Moreover, other language in section 112(m) suggests that Congress
intended for the different terminology in section 112(a)(7) and
112(m)(6) to have the same meaning. In section 112(m)(1), the initial
subsection directing EPA to establish the Great Waters program,
Congress required EPA to evaluate ``any adverse effects to public
health or the environment caused by [HAP] deposition (including effects
resulting from indirect exposure pathways'' (42 U.S.C. 7412(m)(1)(D)).
This provision's use of the section 112(a)(7) defined the term
``adverse environmental effect,'' as inclusive of the same ``effects
resulting from indirect exposure pathways'' as defined in section
112(m)(6), indicates that Congress assumed the scope of environmental
impacts to be covered by section 112(a)(7) and 112(m)(6) would be the
same. Indeed, if Congress had thought otherwise, it would have been
unnecessary for it to have asked EPA to assess whether the other
substantive provisions of section 112 are adequate to prevent the
effects identified in section 112(m)(6). If the environmental effects
in section 112(m)(6) are by definition broader in scope than those
included in the definition of ``adverse environmental effects'' in
section 112(a)(7), the other provisions of section 112 would
necessarily be inadequate to prevent them, and no administrative
expertise on EPA's part would be needed in order to assess this.
While section 112(a)(7) provides as one example of an ``adverse
environmental effect,'' ``significant degradation of environmental
quality over broad areas,'' the use of the term ``widespread'' should
not be viewed as requiring in all cases an environmental effect to
occur in multiple geographic areas. For example, in other contexts, EPA
has interpreted ``widespread'' economic impacts as being those that

[[Page 36441]]

apply to a single affected community. (See EPA final rule, Water
Quality Standards Regulation, 48 FR 51400, 51401 (November 8, 1983); 40
CFR 131.10(g)(6).) In addition, section 112(a)(7) provides as another
example of ``adverse environmental effects'' impacts on populations of
endangered or threatened species; such populations are especially
likely to occur in limited geographic areas. EPA believes Congress did
not intend the ``widespread'' criterion to exclude impacts that might
occur within a limited geographic range that might include, for
example, one of the Great Lakes, the Chesapeake Bay, another Great
Waters waterbody, or a significant portion of such a waterbody. Thus,
to the extent that specific provisions in section 112, such as the
residual risk provisions in section 112(f), allow or require EPA to
prevent ``adverse environmental effects,'' this authority is adequate
to prevent the effects enumerated in section 112(m)(6).

C. Listing of Pollutants

Before EPA may adopt standards or other measures to prevent or
control emissions of a given pollutant under section 112, the pollutant
must first be formally listed as a HAP pursuant to section 112(b).
Section 112(b)(1) provides an initial list of 189 chemicals which
Congress concluded are HAP.\5\ Section 112(b)(2) also provides in part
that the Administrator shall periodically review the list and publish
the results thereof and, where appropriate, revise the list by rule,
adding pollutants which present, or may present, through inhalation or
other routes of exposure, a threat of adverse human health effects or
adverse environmental effects whether through ambient concentrations,
bioaccumulation, deposition, or otherwise (42 U.S.C. 7412(b)(2)).\6\
Section 112(b)(3)(B) further provides that EPA shall add substances to
the list, upon a showing by outside petitioners or on the Agency's own
determination, that ``the substance is an air pollutant and that
emissions, ambient concentrations, bioaccumulation or deposition of the
substance are known to cause or may reasonably be anticipated to cause
adverse effects to human health or adverse environmental effects'' (42
U.S.C. 7412(b)(3)). To assist the Agency in its efforts, section
112(b)(4) provides that, where information on the health or
environmental effects of a substance is not sufficient to make a
determination required by section 112(b), ``the Administrator may use
any authority available to the Administrator to acquire such
information'' (42 U.S.C. 7412(b)(4)). Moreover, section 112(b)(5)
allows EPA to establish, by rulemaking test measures and other analytic
procedures for monitoring and measuring emissions, ambient
concentrations, deposition, and bioaccumulation of hazardous air
pollutants (42 U.S.C. 7312(b)(5)).
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\5\ This list now contains 188 HAP, as a result of EPA's final
decision to remove the compound caprolactam from the section
112(b)(1) list. See 61 FR 30816 (June 18, 1996), codified at 40 CFR
63.60.
\6\ 42 U.S.C. 7412(b)(2) provides:
The Administrator shall periodically review the list established
by this subsection and publish the results thereof and, where
appropriate, revise such list by rule, adding pollutants which
present, or may present, through inhalation or other routes of
exposure, a threat of adverse human health effects (including, but
not limited to, substances which are known to be, or may reasonably
be anticipated to be, carcinogenic, mutagenic, teratogenic,
neurotoxic, which cause reproductive dysfunction, or which are
acutely or chronically toxic) or adverse environmental effects
whether through ambient concentrations, bioaccumulation, deposition,
or otherwise, but not including releases subject to regulation under
subsection (r) of this section as a result of emissions to the air.
No air pollutant which is listed under section 7408(a) of this title
may be added to the list under this section, except that the
prohibition of this sentence shall not apply to any pollutant which
independently meets the listing criteria of this paragraph and is a
precursor to a pollutant which is listed under section 7408(a) of
this title or to any pollutant which is in a class of pollutants
listed under such section. No substance, practice, process or
activity regulated under subchapter VI of this chapter shall be
subject to regulation under this section solely due to its adverse
effects on the environment.
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The EPA believes that, taken together, the provisions of section
112(b) discussed above provide adequate authority to identify and
formally list any HAP which has the potential for causing adverse
public health or environmental effects due to atmospheric deposition.
Of the 15 chemicals or chemical classes that have been identified as
pollutants of concern in the Great Waters program, 13 are already
listed as HAP. The two unlisted pollutants (or pollutant classes) are
nitrogen compounds and the pesticide, Dieldrin. The EPA has authority
to regulate emissions of nitrogen oxides under other sections of the
CAA (e.g., sections 108, 109, 129, 202, and 407). There are currently
no known air emission sources of Dieldrin in the United States. This
substance is a pollutant of concern because it continues to be measured
in the Great Waters at levels considered to be potentially harmful.
However, these levels are the result of prior use of the pesticide and
its recycling in the environment. Thus, there is currently no basis for
adding Dieldrin to the HAP list in section 112.

D. Listing of Sources

Once a pollutant has been listed as a HAP pursuant to section
112(b), EPA is required by section 112(c)(1) to publish and to
periodically review and revise a list of all categories and
subcategories of major sources and area sources of these pollutants (42
U.S.C. 7412(c)(1)).7 Section 112(c)(2) then requires EPA to
establish emissions standards under section 112(d) for the listed
categories and subcategories (42 U.S.C. 7412(c)(2)). Additionally,
section 112(c) imposes requirements to list categories or subcategories
of sources, including area sources, meeting certain specified criteria.
Significant to section 112(m) are the requirements of section
112(c)(6)--EPA is required to identify and to list categories and
subcategories of sources to assure that at least 90 percent of the
aggregate emissions of each of seven specific pollutants are subject to
emission standards under section 112 (d)(2) or (d)(4) and 42 U.S.C.
7412(c)(6)).8 These seven pollutants, alkylated lead
compounds, polycyclic organic matter, hexachlorobenzene, mercury,
polychlorinated biphenyls, 2,3,7,8-tetrachlorodibenzofurans and
2,3,7,8-tetrachlorobenzo-p-dioxin--are identified as pollutants of
concern to the Great Waters, and standards for them must be promulgated
by November 15, 2000.
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\7\ 42 U.S.C. 7412(c)(1) provides:
Not later than 12 months after November 15, 1990, the
Administrator shall publish, and shall from time to time, but no
less often than every 8 years, revise, if appropriate, in response
to public comment or new information, a list of all categories and
subcategories of major sources and area sources (listed under
paragraph (3)) of the air pollutants listed pursuant to subsection
(b) of this section. To the extent practicable, the categories and
subcategories listed under this subsection shall be consistent with
the list of source categories established pursuant to section 7411
of this title and part C of this subchapter. Nothing in the
preceding sentence limits the Administrator's authority to establish
subcategories under this section, as appropriate.
\8\ 42 U.S.C. 7412(c)(6) provides:
With respect to alkylated lead compounds, polycyclic organic
matter, hexachlorobenzene, mercury, polychlorinated biphenyls,
2,3,7,8-tetrachlorodibenzofurans and 2,3,7,8-tetrachlorodibenzo-p-
dioxin, the Administrator shall, not later than 5 years after
November 15, 1990, list categories and subcategories of sources
assuring that sources accounting for not less than 90 per centum of
the aggregate emissions of each such pollutant are subject to
standards under subsection (d)(2) or (d)(4) of this section. Such
standards shall be promulgated not later than 10 years after
November 15, 1990. This paragraph shall not be construed to require
the Administrator to promulgate standards for such pollutants
emitted by electric utility steam generating units.
---------------------------------------------------------------------------

Moreover, section 112(c)(5) provides EPA with broad discretion to
list additional categories and subcategories of area sources of HAP any
time the Agency finds they present a threat of

[[Page 36442]]

adverse effects to human health or the environment, either in the
aggregate or individually (42 U.S.C. 7412(c)(5)).9 Finally,
section 112(c)(3) imposes two additional requirements on EPA. First,
EPA must list each category or subcategory of area sources (i.e.,
nonmajor stationary sources of HAP) which EPA finds presents a threat
of adverse effects to human health or the environment (by such sources
individually or in the aggregate) warranting regulation under section
112; and second, EPA must list, based on actual or estimated aggregate
emissions of a listed pollutant or pollutants, sufficient categories or
subcategories of area sources to ensure that area sources representing
90 percent of the area source emissions of the 30 HAP that present the
greatest threat to public health in the largest number of urban areas
are subject to regulation under section 112 (42 U.S.C.
7412(c)(3).10 These regulations must be promulgated by
November 15, 2000.
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\9\ 42 U.S.C. 7412(c)(5) provides:
In addition to those categories and subcategories of sources
listed pursuant to paragraphs (1) and (3), the Administrator may at
any time list additional categories and subcategories of sources of
hazardous air pollutants according to the same criteria for listing
applicable under such paragraphs. In the case of source categories
and subcategories listed after publication of the initial list
required under paragraph (1) or (3), emission standards under
subsection (d) of this section for the category or subcategory shall
be promulgated within 10 years after November 15, 1990, or within 2
years after the date on which such category or subcategory is
listed, whichever is later.
\10\ 42 U.S.C. 7412(c)(3) provides:
The Administrator shall list under this subsection each category
or subcategory of area sources which the Administrator finds
presents a threat of adverse effects to human health or the
environment (by such sources individually or in the aggregate)
warranting regulation under this section. The Administrator shall,
not later than 5 years after November 15, 1990, and pursuant to
subsection (k)(3)(B) of this section, list, based on actual or
estimated aggregate emissions of a listed pollutant or pollutants,
sufficient categories or subcategories of area sources to ensure
that area sources representing 90 percent of the area source
emissions of the 30 hazardous air pollutants that present the
greatest threat to public health in the largest number of urban
areas are subject to regulation under this section. Such standards
shall be promulgated not later than 10 years after November 15,
1990.
---------------------------------------------------------------------------

In its use of the terms ``category'' and ``subcategory'' of
sources, the CAA does not provide definitive guidance and, thus, EPA's
discretion in how to apply those terms is broad. The CAA does provide
definitions of ``major,'' ``stationary'' and ``area'' sources, the
latter meaning any stationary source of HAP that is not a major source
and excluding motor vehicles or nonroad vehicles subject to title II of
the CAA (42 U.S.C. 7412(a)(2).) 11 Thus, section 112(c)
provides for the listing of stationary sources only and does not reach
such sources as motor vehicles, aircraft, nonroad engines or vehicles
such as locomotives.
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\11\ 42 U.S.C. 7412(a)(2) provides:
The term ``area source'' means any stationary source of
hazardous air pollutants that is not a major source. For purposes of
this section, the term ``area source'' shall not include motor
vehicles or nonroad vehicles subject to regulation under subchapter
II of this chapter.
---------------------------------------------------------------------------

While this might appear to be a deficiency in the scope of section
112, to the extent that emissions from such sources can cause or
contribute to significant and harmful atmospheric deposition of HAP,
they can be regulated under other provisions of the CAA such that
section 112 is not necessarily rendered ``inadequate'' due to its focus
on stationary sources. For example, in the case of emissions from motor
vehicles, section 202(a)(1) requires EPA to promulgate emissions
standards for any air pollutants from new motor vehicles or their
engines which in the Administrator's judgment cause or contribute to
air pollution which may reasonably be anticipated to endanger public
health or welfare (42 U.S.C. 7521(a)(1)). In addition, section
211(k)(1) requires EPA to promulgate requirements for the reformulation
of gasoline to control toxic air pollutants from motor vehicles which
reflect the greatest degree of emission reduction achievable through
the reformulation of gasoline, taking into consideration cost and
various factors. ``Toxic air pollutants'' are defined to include
polcyclic organic matter (POM), a pollutant of concern for the Great
Waters (42 U.S.C. 7545(k)(1), (10)(C)). Finally, section 213(a)(4)
allows EPA to promulgate regulations applicable to emissions from
nonroad engines or vehicles, in addition to those covering ozone and
carbon monoxide, whenever the Administrator determines that those
emissions may reasonably be anticipated to endanger public health or
welfare (42 U.S.C. 7547(a)(4)).
Based on this analysis, EPA believes that its authority to list
stationary sources of the listed HAP is sufficiently comprehensive for
domestic stationary sources, including small stationary sources. The
EPA is not aware of any basis by which a category or subcategory of
stationary sources of a listed HAP that is of concern under the Great
Waters program could evade listing for regulation under section 112.
While this authority is limited to stationary sources and thus does not
authorize regulation of mobile sources under section 112, EPA's other
CAA authority provides sufficient authority to address HAP emissions
from nonstationary sources subject to the CAA such that the listing
provisions of section 112(c) are adequate for purposes of section
112(m)(6).

E. Regulations to Control Emissions of Pollutants

1. Maximum Achievable Control Technology and Generally Available
Control Technology Standards
Once a pollutant is formally listed under section 112(b), and EPA
has also listed the stationary source categories or subcategories of
that pollutant, the Agency is required by section 112(d)(2) to
promulgate regulations to establish emission standards requiring the
maximum degree of reduction in emissions of the HAP, including a
prohibition on such emissions where achievable, that the Administrator,
taking into consideration the cost of achieving these emission
reductions and any non-air quality health and environmental impacts and
energy requirements, determines is achievable for new or existing
sources in the category or subcategory to which the emission standard
applies (42 U.S.C. 7412(d)(2)).12 These standards are
referred to as MACT standards, and they must require application of
measures, processes, methods, systems or techniques which reduce the
volume of, or eliminate, emissions of HAP. Such reduction or
elimination of HAP may occur through process changes,

[[Page 36443]]

substitution of materials or other modifications, enclosing systems or
processes to eliminate emissions, and taking other specified measures.
Id.
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\12\ 42 U.S.C. Sec. 7412(d)(2) provides:
Emissions standards promulgated under this subsection and
applicable to new or existing sources of hazardous air pollutants
shall require the maximum degree of reduction in emissions of the
hazardous air pollutants subject to this section (including a
prohibition on such emissions, where achievable) that the
Administrator, taking into consideration the cost of achieving such
emission reduction, and any non-air quality health and environmental
impacts and energy requirements, determines is achievable for new or
existing sources in the category or subcategory to which such
emission standard applies, through application of measures,
processes, methods, systems or techniques including, but not limited
to, measures which--
(A) reduce the volume of, or eliminate emissions of, such
pollutants through process changes, substitution of materials or
other modifications,
(B) enclose systems or processes to eliminate emissions,
(C) collect, capture or treat such pollutants when released from
a process, stack, storage or fugitive emissions point,
(D) are design, equipment, work practice, or operational
standards (including requirements for operator training or
certification) as provided in subsection (h) of this section, or
(E) are a combination of the above.
None of the measures described in subparagraphs (A) through (D)
shall, consistent with the provisions of section 7414 of
this title, in any way compromise any United States patent or United
States trademark right, or any confidential business information, or
any trade secret or any other intellectual property right.
---------------------------------------------------------------------------

Subsection 112(d)(3) goes on to establish that these emission
standards may not be less stringent than the emission control that is
achieved in practice by the best controlled similar source, in the case
of new sources; by the average emission limitation achieved by the best
performing 12 percent of the existing sources; or by the average
emission limitation achieved by the best performing five existing
sources, where there are fewer than 30 sources in the category or
subcategory, whichever is applicable (42 U.S.C. 7412(d)(3)).
13 Moreover, for source categories or subcategories of area
sources listed under section 112(c), section 112(d)(5) allows EPA, in
lieu of requiring MACT for such sources, to promulgate standards which
provide for the use of GACT) or management practices to reduce
emissions of HAP (42 U.S.C. 7412(d)(5)). Additional provisions are made
for emission standards for coke ovens, and an exclusion from regulation
is provided for radionuclides and their sources licensed by the Nuclear
Regulatory Commission if certain findings are made. Finally, section
112(d)(7) provides that any more stringent requirements or emissions
limitations established under provisions of the Act other than section
112 or under State authority are preserved (42 U.S.C. 7412(d)(7)).
---------------------------------------------------------------------------

\13\ 42 U.S.C. Sec. 7412(d)(3) provides:
The maximum degree of reduction in emissions that is deemed
achievable for new sources in a category or subcategory shall not be
less stringent than the emission control that is achieved in
practice by the best controlled similar source, as determined by the
Administrator. Emissions standards promulgated under this subsection
for existing sources in a category or subcategory may be less
stringent than standards for new sources in the same category or
subcategory but shall not be less stringent, and may be more
stringent than--
(A) the average emission limitation achieved by the best
performing 12 percent of the existing sources (for which the
Administrator has emissions information), excluding those sources
that have, within 18 months before the emission standard is proposed
or within 30 months before such standard is promulgated, whichever
is later, first achieved a level of emission rate or emission
reduction which complies, or would comply if the source is not
subject to such standard, with the lowest achievable emission rate
(as defined by section 7501 of this title) applicable to the source
category and prevailing at the time, in the category or subcategory
for categories and subcategories with 30 or more sources, or
(B) the average emission limitation achieved by the best
performing 5 sources (for which the Administrator has or could
reasonably obtain emissions information) in the category or
subcategory for categories or subcategories with fewer than 30
sources.
---------------------------------------------------------------------------

While section 112(d)(5) of the CAA allows EPA to restrict
application of MACT standards to major sources and to promulgate less
stringent GACT standards for area sources, the Agency is not required
to do so. As discussed earlier in this notice, although major sources
are defined as those which emit 10 tons per year or more of any HAP or
25 tons per year of any combination of HAP, EPA is granted discretion
under section 112(a)(1) to establish a lesser quantity emissions rate
(LQER) for a major source on the basis of the potency of the air
pollutant, persistence, potential for bioaccumulation, other
characteristics of the air pollutant, or other relevant factors (42
U.S.C. 7412(a)(1)). In addition, EPA interprets section 112(d)(5) as
authorizing the Administrator to establish GACT standards for area
sources when the imposition of MACT is determined to be unreasonable
(See 60 FR 4948, 4953, January 25, 1995). Thus, while EPA is permitted
by section 112(d)(5) to establish standards or requirements which
provide for the use of GACT or management practices to reduce emissions
of HAP, EPA retains discretion to subject area source categories or
subcategories to MACT where appropriate.
While the provisions of section 112(d) require EPA to focus the
potentially more stringent performance standards and control efforts on
major sources, they also allow EPA the discretion to apply these
requirements to smaller sources.
Section 112(e) establishes an aggressive schedule for establishing
section 112(d) standards. In addition to requiring all emission
standards for all categories and subcategories to be promulgated no
later than November 15, 2000, section 112(e)(2) requires EPA to
consider the known or anticipated adverse effects of HAP on public
health and the environment and other factors when determining
priorities for promulgating section 112(d) standards (42 U.S.C.
7412(e)(2)).
2. Residual Risk Standards
The Agency expects to achieve the vast majority of HAP emissions
reductions under section 112 through application of the section 112(d)
MACT and GACT programs. It must be stressed, however, that MACT and
GACT standards are not required to achieve a specified health-based
result or prevent specified environmental effects. Consequently,
section 112 provides another mechanism to address situations where
additional reductions are necessary to protect the public health or
prevent an adverse environmental effect, even after imposition of
controls such as MACT or GACT. The EPA is required by section
112(f)(2)(A) to promulgate more stringent standards within 8 years
after the adoption of the initial MACT standards, if such action is
necessary to provide an ample margin of safety to protect public health
or to prevent, taking into consideration costs, energy, safety, and
other relevant factors, an adverse environmental effect (42 U.S.C.
7412(f)(2)(A)).14 Whenever MACT standards under section
112(d) applicable to a source category or subcategory emitting a
pollutant 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 one in one million, standards are required under section
112(f). If providing an ample margin of safety to protect public health
is not adequate to prevent an adverse environmental effect, a more
stringent standard must be promulgated. In addition, while section 112
does not require EPA to conduct residual risk analyses for GACT
standards, the Agency retains the discretion to establish residual risk
standards in appropriate cases after application of GACT. The EPA views
this provision as providing the Agency the authority to prevent any
remaining adverse environmental effect, as defined in section
112(a)(7), presented by HAP emissions from stationary sources after

[[Page 36444]]

imposition of controls under section 112(d).
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\14\ 42 U.S.C. Sec. 7412(f)(2)(A) provides:
If Congress does not act on any recommendation submitted under
paragraph (1), the Administrator shall, within 8 years after
promulgation of standards for each category or subcategory of
sources pursuant to subsection (d) of this section, promulgate
standards for such category or subcategory if promulgation of such
standards is required in order to provide an ample margin of safety
to protect public health in accordance with this section (as in
effect before November 15, 1990) or to prevent, taking into
consideration costs, energy, safety, and other relevant factors, an
adverse environmental effect. Emission standards promulgated under
this subsection shall provide an ample margin of safety to protect
public health in accordance with this section (as in effect before
November 15, 1990), unless the Administrator determines that a more
stringent standard is necessary to prevent, taking into
consideration costs, energy, safety, and other relevant factors, an
adverse environmental effect. If standards promulgated pursuant to
subsection (d) of this section and applicable to a category or
subcategory of sources emitting a pollutant (or pollutants)
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 one in one million, the Administrator shall promulgate
standards under this subsection for such source category.
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As discussed earlier in today's notice, for purposes of section 112
in general, the term ``adverse environmental effect'' is defined by
section 112(a)(7) to include ``any significant and widespread adverse
effect, which may reasonably be anticipated, to wildlife, aquatic life,
or other natural resources, including adverse impacts on populations of
endangered or threatened species or significant degradation of
environmental quality over broad areas'' (42 U.S.C. 7412(a)(7)). Again,
EPA interprets the scope of this defined term to apply as broadly as
the effects discussed in section 112(m)(6). Moreover, section
112(f)(2)(A) allows the Agency to promulgate appropriate further
emissions standards for a source category or subcategory as necessary
to provide an ample margin of safety to protect public health or to
prevent any adverse environmental effect. Where the risk of harm to
public health or the risk of an adverse environmental effect is
presented by only certain sources within a source category or
subcategory, EPA believes it may appropriately tailor the section
112(f)(2) regulations applicable to the source category or subcategory
such that the requirement to achieve additional emissions reductions or
undertake other control efforts is imposed only on those sources within
the category or subcategory that present the risk. This approach would
avoid possible unnecessary imposition of these risk-based requirements
on any sources in the category or subcategory whose emissions do not
present such risk, and allow EPA to most effectively craft the section
112(f)(2)(A) requirements applicable to the category or subcategory to
specifically address the risks at issue. This interpretation is
supported by section 112(f)(2)(A)'s provision that EPA is authorized to
promulgate additional standards to prevent ``an'' adverse environmental
effect. The reference to ``adverse environmental effect'' in the
singular contemplates a situation where, for example, an adverse
environmental effect is presented by a limited number of sources within
a source category or subcategory, over a limited geographic or
situational range. Moreover, while EPA recognizes that section
112(f)(2)(A) requires the Agency to consider cost, energy, safety and
other relevant factors when establishing a more stringent limit than is
necessary to protect the public health with an ample margin of safety,
EPA has substantial discretion in determining how to evaluate those
factors and what weight to give them. (See, New York v. Reilly, 969
F.2d 1147, 1150 (D.C. Cir. 1992) (citing Center for Auto Safety v.
Peck, 751 F.2d 1336, 1342 (D.C, Cir. 1985), Weyerhaeuser Co. v. Costle,
590 F.2d 1011, 1045 (D.C. Cir. 1978)(Congress ``left EPA with
discretion to decide how to account for the consideration of factors,
and how much weight to give each factor'').) The presence of these
factors further supports EPA's view that it has substantial discretion
in developing the most appropriate approaches to addressing residual
risks presented by source categories or subcategories. For example, EPA
could use its section 112(f) residual risk authority to address adverse
environmental effects to Great Waters waterbodies that are associated
with the atmospheric deposition of HAP emitted by particular sources
within source categories.
In developing additional standards to address residual risk
following adoption of MACT standards, section 112(f) states that the
Administrator shall not be required to conduct any residual risk review
or promulgate additional emission limitations for any category or
subcategory of area sources that is listed under section 112(c)(3) for
which a GACT emission standard is promulgated pursuant to section
112(d)(5) (42 U.S.C. 7412(f)(5)).15 In effect, this
provision grants discretionary authority to EPA to provide an exemption
for area sources from the more stringent residual risk standards. It is
important to emphasize, however, that this exemption is wholly within
EPA's discretion so that, should the Agency determine that emissions of
one or more HAP from area sources within a source category or
subcategory pose unacceptable remaining risks to human health or the
environment, even after application of section 112(d) emission
controls, it has authority under section 112(f) to adopt more stringent
standards governing these sources as well. This is in addition to EPA's
discretionary authority to apply more stringent MACT standards to area
sources in the first instance. Thus, the CAA provides authority in
section 112(f)(2)(A) to take action with respect to stationary source
categories or subcategories as needed to prevent the same sorts of
effects identified under section 112(m)(6), and to focus such action so
that the duty to undertake measures in compliance with the residual
risk standard is triggered by sources within the subject category or
subcategory that present the risk of causing these effects.
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\15\ 42 U.S.C. 7412(f)(5) provides:
The Administrator shall not be required to conduct any review
under this subsection or promulgate emission limitations under this
subsection for any category or subcategory of area sources that is
listed pursuant to subsection (c)(3) of this section and for which
an emission standard is promulgated pursuant to section (d)(5) of
this section.
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F. Urban Area Source Program

Section 112(k) requires EPA to implement the urban area source
program. After conducting research to monitor, analyze and consider HAP
emissions from area sources in urban areas and their public health
risks, EPA is required under section 112(k)(3)(B)(I) to identify the 30
HAP emitted from area sources that present the greatest threat to
public health in the largest number of urban areas (42 U.S.C.
7412(k)(3)(B)(I)). The EPA must then identify the source categories for
listing under section 112(c), assuring that sources accounting for at
least 90 percent of the aggregate emissions of each of the 30
identified HAP will be subject to standards pursuant to section 112(d)
(42 U.S.C. 7412(k)(3)(B)(ii)).
Section 112(k)(3)(C) then requires EPA to prepare a strategy
including a schedule of specific actions to reduce public health risks
posed by emissions of HAP by area sources, which would be implemented
by EPA or the States under several Federal and State environmental
statutes. This strategy must achieve at least a 75 percent reduction in
the incidence of cancer attributable to exposure to HAP emitted by
stationary sources (42 U.S.C. 7412(k)(3)(C)). In addition to this
national urban area source strategy, EPA shall also encourage and
support areawide strategies developed by State and local agencies
intended to reduce risks from emissions by area sources in particular
urban areas, and prepare guidelines for control technologies or
management practices which may be applicable to various source
categories (42 U.S.C. 7412(k)(4)).
To the extent that the urban area source program identifies and
achieves reductions in HAP that are also pollutants of concern in the
Great Waters, section 112(k) provides an additional tool for reducing
HAP emissions that present serious adverse effects to the public health
or environment through atmospheric deposition. For example, this
program could result in significant reductions in emissions of POM,
with incidental benefits for the specific environmental values required
to be protected under the Great Waters provisions, if POM is identified
as one of the 30 most hazardous air pollutants emitted by area sources.

[[Page 36445]]

G. Studies and Reports to Congress

1. Mercury
Section 112(n)(1)(B) requires EPA to study and report to Congress
on mercury emissions from electric utility steam generating units,
municipal waste combustion units, and other sources, including area
sources (42 U.S.C. 7412(n)(1)(B)). 16 This study must
consider the rate and mass of such mercury emissions, the health and
environmental effects of the emissions, available technologies to
control these emissions, and the costs of applying such technology.
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\16\ 42 U.S.C. 7412(n)(1)(B) provides:
The Administrator shall conduct, and transmit to the Congress
not later than 4 years after November 15, 1990, a study of mercury
emissions from electric utility steam generating units, municipal
waste combustion units, and other sources, including area sources.
Such study shall consider the rate and mass of such emissions, the
health and environmental effects of such emissions, technologies
which are available to control such emissions, and the costs of such
technologies.
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When the report becomes final, the results of the study will be
helpful in prioritizing mercury reduction strategies.
2. Electric Utilities
Under section 112(n)(1)(A), EPA must also study and report to
Congress on the hazards to public health reasonably anticipated to
occur as a result of emissions of HAP by electric utility steam
generating units after imposition of the CAA requirements (42 U.S.C.
7412(n)(1)(A)).17 This report must develop and describe
alternative control strategies for emissions which may warrant
regulation under section 112, and EPA is required by section
112(n)(1)(A) to regulate electric utility steam generating units under
section 112 if EPA finds such regulation is necessary and appropriate
after considering the study.
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\17\ 42 U.S.C. 7412(n)(1)(A) provides:
The Administrator shall perform a study of the hazards to public
health reasonably anticipated to occur as a result of emissions by
electric utility steam generating units of pollutants listed under
subsection (b) of this section after imposition of the requirements
of this chapter. The Administrator shall report the results of this
study to the Congress within 3 years after November 15, 1990. The
Administrator shall develop and describe in the Administrator's
report to Congress alternative control strategies for emissions
which may warrant regulation under this section. The Administrator
shall regulate electric utility steam generating units under this
section, if the Administrator finds such regulation is appropriate
and necessary after considering the results of the study required by
this subparagraph.
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These provisions provide EPA the authority to achieve reductions in
HAP emissions from electric utilities as necessary and appropriate to
prevent reasonably anticipated hazards to public health and the
environment, which would have benefits for the Great Waters. For
example, if EPA determines that regulation of mercury emissions from
electric utilities is necessary and appropriate, EPA would have the
full set of regulatory tools available under section 112 to address
those emissions, including section 112(f), as well as any additional
alternative control strategies the Agency has identified in its Report
to Congress.

H. Solid Waste Incineration Units

Solid waste incineration units such as those that combust municipal
waste, medical waste, and industrial and commercial waste, are
regulated under sections 111 and 129 of the CAA. While this is not
literally a section 112 program, the types of standards to be applied
under section 129(a)(2) are MACT standards, and shall be based on
methods and technologies for removal or destruction of pollutants
before, during or after combustion. For new units, they must
incorporate siting requirements that minimize, on a site-specific
basis, to the maximum extent practicable, potential risks to public
health or the environment (42 U.S.C. 7429(a)(2), (3)).18
These standards are required for certain HAP (as well as specified
criteria pollutants) identified in section 129: solid waste
incineration units must be subjected to numerical emission limitations
for lead, cadmium, mercury, dioxins and dibenzofurans (42 U.S.C.
7429(a)(4)).19 Moreover, section 129(h)(3) requires EPA to
promulgate residual risk standards under section 112(f)(2) for
emissions of these pollutants from solid waste incineration units, if
such standards are required in order to provide an ample margin of
safety to protect the public health or to prevent an adverse
environmental effect as set forth in section 112(f)(2)(A) (42 U.S.C.
7429(h)(3)).20 Finally, State and local government agencies
are authorized under section 129(h)(1) to adopt and enforce
regulations, requirements, limitations or standards relating to solid
waste incineration units that are more stringent than those promulgated
by EPA (42 U.S.C. 7429(h)(1); (b)(2)).
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\18\ 42 U.S.C. 7429(a)(2) and (3) provide:
(2) Standards applicable to solid waste incineration units
promulgated under section 7411 of this title and this section shall
reflect the maximum degree of reduction in emissions of air
pollutants listed under section (a)(4) that the Administrator,
taking into consideration the cost of achieving such emission
reduction, and any non-air quality health and environmental impacts
and energy requirements, determines is achievable for new or
existing units in each category. The Administrator may distinguish
among classes, types (including mass-burn, refuse-derived fuel,
modular and other types of units), and sizes of units within a
category in establishing such standards. The degree of reduction in
emissions that is deemed achievable for new units in a category
shall not be less stringent than the emissions control that is
achieved in practice by the best controlled similar unit, as
determined by the Administrator. Emissions standards for existing
units in a category may be less stringent than standards for new
units in the same category but shall not be less stringent than the
average emissions limitation achieved by the best performing 12
percent of units in the category (excluding units which first met
the lowest achievable emissions rates 18 months before the date such
standards are proposed or 30 months before the date such standards
are promulgated, whichever is later).
(3) Standards under section 7411 of this title and this section
applicable to solid waste incineration units shall be based on
methods and technologies for removal or destruction of pollutants
before, during, or after combustion, and shall incorporate for new
units siting requirements that minimize, on a site specific basis,
to the maximum extent practicable, potential risks to public health
or the environment.
\19\ 42 U.S.C. 7429(a)(4) provides:
The performance standards promulgated under section 7411 of this
title and this section and applicable to solid waste incineration
units shall specify numerical emission limitations for the following
substances or mixtures: particulate matter (total and fine), opacity
(as appropriate), sulfur dioxide, hydrogen chloride, oxides of
nitrogen, carbon monoxide, lead, cadmium, mercury, and dioxins and
dibenzofurans. The Administrator may promulgate numerical emissions
limitations or provide for the monitoring of postcombustion
concentrations of surrogate substances, parameters or periods of
residence time in excess of stated temperatures with respect to
pollutants other than those listed in this paragraph.
\20\ 42 U.S.C. 7429(h)(3) provides:
The Administrator shall promulgate standards under section
7412(f) of this title for a category of solid waste incineration
units, if promulgation of such standards is required under section
7412(f) of this title. For purposes of this preceding sentence
only--
(A) the performance standards under subsection (a) of this
section and section 7411 of this title applicable to a category of
solid waste incineration units shall be deemed standards under
section 7412(d)(2) of this title, and
(B) the Administrator shall consider and regulate, if required,
the pollutants listed under subsection (a)(4) of this section and no
others.
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This program will result in significant reductions in emissions of
pollutants of concern for the Great Waters from solid waste
incineration units. Especially in light of the authority to subject
these units to residual risk standards under section 112(f)(2) and
EPA's substantial discretion afforded under that subsection, EPA
believes that it has adequate authority to prevent solid waste
incineration unit emissions of the specified HAP in section 129(a)(4)
from causing serious adverse public health and environmental effects
associated with deposition to the Great Waters.

IV. Determinations of Adequacy and No Need for Further Regulations

Based on available information and on the foregoing analysis,
guided by EPA's interpretation of the statutory

[[Page 36446]]

requirements of section 112(m), EPA believes that the other provisions
of section 112 are adequate to prevent serious, adverse effects to
public health and serious or widespread environmental effects
associated with the deposition of HAP which are emitted by stationary
sources for which EPA has authority and jurisdiction under section 112
to regulate. As a result, the Agency also believes that no further
emissions standards or control measures under section 112(m)(6), beyond
those authorized or required by the other provisions of section 112,
are necessary and appropriate at this time. The EPA further believes
that even if section 112 were found to be inadequate under section
112(m)(6), because much scientific information is still lacking
concerning such things as the relative contribution of air emissions of
pollutants of concern to adverse effects, it would not be possible at
this time for the Agency to conclude confidently that further
regulatory actions beyond those authorized or required to be taken
under section 112 are necessary and appropriate. The EPA solicits
comments on the draft determination, and on the analysis contained in
today's notice. The Agency reserves its right to reconsider these draft
determinations if the public comments on the draft determinations
convince EPA that it is incorrect in its analysis, or if future events
or additional information indicate EPA's determinations are not
accurate. In addition, when EPA finalizes these determinations, EPA
reserves its right to promulgate any necessary and appropriate further
regulations pursuant to section 112(m)(6), in the event that EPA in the
future, based on new information, revisits and reverses these
determinations.
The EPA is committed to continuing its analyses, research and
assessments of all aspects of atmospheric transport, deposition, fate
and effects of hazardous air pollutants emitted by section 112 sources.
The EPA is further committed to faithfully implementing the mandates
and authorities under section 112 of the CAA, and to pursuing other
available authorities, as appropriate, to minimize unreasonable threats
to humans and to the environment as a result of exposure to toxic
pollutants, whether such exposures result directly from emissions into
the air, through introduction to watersheds or waterbodies, or through
other pathways. The EPA will continue to work cooperatively with the
National Oceanic and Atmospheric Administration and the scientific
community to refine methods for measuring or estimating atmospheric
transport and deposition of HAP in order to more reliably characterize
and quantify the significance of atmospheric deposition to
environmental quality.
It is important to distinguish between EPA's draft determinations
in this notice and the Agency's judgments about the extent to which
adverse effects may be occurring due to atmospheric deposition of HAP
from all sources, or about the extent to which additional actions
within the scope of its other authorities under section 112 may be
warranted. In today's notice, EPA is announcing only that it believes
it has adequate authority under section 112 to prevent the section
112(m)(6) enumerated adverse health or environmental effects associated
with emissions of HAP from sources which section 112 was intended to
regulate, and that, at this time, EPA does not believe that further
emissions standards or control measures under section 112(m)(6) to
prevent such effects, beyond those that are authorized or required by
the other provisions of section 112, are necessary or appropriate for
stationary sources of HAP. These draft determinations in no way
represent a conclusion on EPA's part that air deposition of HAP does
not currently cause or contribute to adverse effects to the public
health or the environment.

Dated: June 30, 1997.
Carol Browner,
Administrator.
[FR Doc. 97-17597 Filed 7-3-97; 8:45 am]
BILLING CODE 6560-50-P

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A97-17597. Public record. Not legal advice.