[Federal Register: July 6, 2005 (Volume 70, Number 128)]
[Rules and Regulations]
[Page 39103-39172]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr06jy05-22]
[[Page 39103]]
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Part III
Environmental Protection Agency
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40 CFR Part 51
Regional Haze Regulations and Guidelines for Best Available Retrofit
Technology (BART) Determinations; Final Rule
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 51
[FRL-7925-9]
RIN 2060-AJ31
Regional Haze Regulations and Guidelines for Best Available
Retrofit Technology (BART) Determinations
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: On July 1, 1999, EPA promulgated regulations to address
regional haze (64 FR 35714). These regulations were challenged, and on
May 24, 2002, the U.S. Court of Appeals for the District of Columbia
Circuit issued a ruling vacating the regional haze rule in part and
sustaining it in part. American Corn Growers Ass'n v. EPA, 291 F.3d 1
(D.C. Cir. 2002). Today's rule addresses the court's ruling in that
case.
In addition, prior to the court's decision, EPA had proposed
guidelines for implementation of the Best Available Retrofit Technology
(BART) requirements under the regional haze rule, (66 FR 38108, July
20, 2001). The proposed guidelines were intended to clarify the
requirements of the regional haze rule's BART provisions. We proposed
to add the guidelines and also proposed to add regulatory text
requiring that these guidelines be used for addressing BART
determinations under the regional haze rule. In addition, we proposed
one revision to guidelines issued in 1980 for facilities contributing
to ``reasonably attributable'' visibility impairment.
In the American Corn Growers case, the court vacated and remanded
the BART provisions of the regional haze rule. In response to the
court's ruling, on May 5, 2004 we proposed new BART provisions and
reproposed the BART guidelines. The American Corn Growers court also
remanded to the Agency its decision to extend the deadline for the
submittal of regional haze plans. Subsequently, Congress amended the
deadlines for regional haze plans (Consolidated Appropriations Act for
Fiscal Year 2004, Public Law 108-199, January 23, 2004). The May 5,
2004 proposed rule also contained an amendment to the regional haze
rule to conform to the new statutory deadlines.
We received numerous comments on both the July 20, 2001 proposal
and the May 5, 2004 reproposal. Today's final rule reflects our review
of the public comments.
DATES: The regulatory amendments announced herein take effect on
September 6, 2005.
ADDRESSES: Docket. All documents in the docket are listed in the
EDOCKET index at http://www.epa.gov/edocket. Although listed in the
index, some information is not publicly available, i.e., CBI or other
information whose disclosure is restricted by statute. Certain other
material, such as copyrighted material, is not placed on the Internet
and will be publicly available only in hard copy form. Publicly
available docket materials are available either electronically in
EDOCKET or in hard copy at the OAR Docket, EPA/DC, EPA West, Room B102,
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
(202) 566-1744, and the telephone number for the OAR Docket is (202)
566-1742.
FOR FURTHER INFORMATION CONTACT: Kathy Kaufman at (919) 541-0102 or by
e-mail at Kaufman.Kathy@epa.gov or Todd Hawes at 919-541-5591 or by e-
mail Hawes.Todd@epa.gov.
SUPPLEMENTARY INFORMATION:
Regulated Entities. This final rule will affect the following:
State and local permitting authorities and Indian Tribes containing
major stationary sources of pollution affecting visibility in federally
protected scenic areas.
This list is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be regulated by this
action. This list gives examples of the types of entities EPA is now
aware could potentially be regulated by this action. Other types of
entities not listed could also be affected. To determine whether your
facility, company, business, organization, etc., is regulated by this
action, you should examine the applicability criteria in Part II of
this preamble. If you have any questions regarding the applicability of
this action to a particular entity, consult the people listed in the
preceding section.
Outline. The contents of today's preamble are listed in the
following outline.
I. Overview of Today's Proposed Actions
II. Background
A. Regional Haze Rule
B. Partial Remand of the Regional Haze Rule in American Corn
Growers
C. Changes in Response to American Corn Growers
D. Center for Energy and Economic Development v. EPA
E. Relationship Between BART and the Clean Air Interstate Rule
(CAIR)
F. Overview of the BART Process
III. Detailed Discussion of the BART Guidelines
A. Introduction
B. Scope of the Rule--Whether to Require States to Follow the
Guidelines for All BART Sources
C. How to Identify BART-Eligible Sources
D. How to Determine Which BART-Eligible Sources are Subject to
BART
E. The BART Determination Process
IV. Effect of This Rule on State Options for Using Alternative
Strategies In Lieu of Source-by-Source BART
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 Risks and Safety Risks
H. Executive Order 13211: Actions That Significantly Affect
Energy Supply, Distribution, or Use.
I. National Technology Transfer Advancement Act
J. Executive Order 12898: Federal Actions to Address
Environmental Justice in Minority Populations and Low-Income
Populations
I. Overview of Today's Actions
Today's rulemaking provides the following changes to the regional
haze regulations:
(1) Revised regulatory text in response to the American Corn
Growers court's remand, to require that the BART determination include
an analysis of the degree of visibility improvement resulting from the
use of control technology at each source subject to BART,
(2) Revised regulatory text in 40 CFR 51.308(b) and deletion of 40
CFR 51.308(c) Options for regional planning in response to
Congressional legislation amending the deadlines for submittal of
regional haze implementation plans. This provision had provided for an
alternative process for States to submit regional haze implementation
plans in attainment areas,
(3) BART guidelines, contained in a new Appendix Y to 40 CFR part
51,
(4) New and revised regulatory text, to be added to 40 CFR
51.308(e), regarding the use of Appendix Y in establishing BART
emission limits, and
(5) Revised regulatory language at 40 CFR 51.302 to clarify the
relationship between New Source Performance Standards (NSPS) and BART
for reasonably attributable visibility impairment.
How This Preamble Is Structured. Section II provides background on
the
[[Page 39105]]
Clean Air Act (CAA) BART requirements as codified in the regional haze
rule, on the D.C. Circuit Court decision which remanded parts of the
rule, and on the April 2004 reproposal responding to the remand.
Section III discusses specific issues in the BART guidelines in more
detail, including background on each issue, major comments we received
on the July 2001 proposal and May 2004 reproposal, and our responses to
those comments. Section IV provides a discussion of how this rulemaking
complies with the requirements of Statutory and Executive Order
Reviews.
II. Background
A. The Regional Haze Rule
In 1999, we published a final rule to address a type of visibility
impairment known as regional haze (64 FR 35714, July 1, 1999). The
regional haze rule requires States to submit implementation plans
(SIPs) to address regional haze visibility impairment in 156 Federally-
protected parks and wilderness areas. These 156 scenic areas are called
``mandatory Class I Federal areas'' in the Clean Air Act (CAA)\1\ but
are referred to simply as ``Class I areas'' in today's rulemaking. The
1999 rule was issued to fulfill a long-standing EPA commitment to
address regional haze under the authority and requirements of sections
169A and 169B of the CAA.
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\1\ See, e.g. CAA Section 169A(a)(1).
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As required by the CAA, we included in the final regional haze rule
a requirement for BART for certain large stationary sources that were
put in place between 1962 and 1977. We discussed these requirements in
detail in the preamble to the final rule (64 FR at 35737-35743). The
regulatory requirements for BART were codified at 40 CFR 51.308(e) and
in definitions that appear in 40 CFR 51.301.
The CAA, in sections 169A(b)(2)(A) and in 169A(g)(7), uses the term
``major stationary source'' to describe those sources that are the
focus of the BART requirement. To avoid confusion with other CAA
requirements which also use the term ``major stationary source'' to
refer to a somewhat different population of sources, the regional haze
rule uses the term ``BART-eligible source'' to describe these sources.
The BART-eligible sources are those sources which have the potential to
emit 250 tons or more of a visibility-impairing air pollutant, were put
in place between August 7, 1962 and August 7, 1977, and whose
operations fall within one or more of 26 specifically listed source
categories. Under the CAA, BART is required for any BART-eligible
source which a State determines ``emits any air pollutant which may
reasonably be anticipated to cause or contribute to any impairment of
visibility in any such area.'' Accordingly, for stationary sources
meeting these criteria, States must address the BART requirement when
they develop their regional haze SIPs.
Section 169A(g)(7) of the CAA requires that States must consider
the following factors in making BART determinations:
(1) The costs of compliance,
(2) The energy and nonair quality environmental impacts of
compliance,
(3) Any existing pollution control technology in use at the source,
(4) The remaining useful life of the source, and
(5) The degree of improvement in visibility which may reasonably be
anticipated to result from the use of such technology.
These statutory factors for BART were codified at 40 CFR
51.308(e)(1)(ii).
In the preamble to the regional haze rule, we committed to issuing
further guidelines to clarify the requirements of the BART provision.
The purpose of this rulemaking is to fulfill this commitment by
providing guidelines to assist States as they identify which of their
BART-eligible sources should undergo a BART analysis (i.e., which are
``sources subject to BART'') and select controls in light of the
statutory factors listed above (``the BART determination'').
B. Partial Remand of the Regional Haze Rule in American Corn Growers v.
EPA
In response to challenges to the regional haze rule by various
petitioners, the D.C. Circuit in American Corn Growers \2\ issued a
ruling striking down the regional haze rule in part and upholding it in
part. This section discusses the court's opinion in that case as
background for the discussion of specific changes to the regional haze
rule and the BART guidelines presented in the next two sections,
respectively.
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\2\ American Corn Growers et al. v. EPA, 291 F.3d 1 (2002).
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We explained in the preamble to the 1999 regional haze rule that
the BART requirements in section 169A(b)(2)(A) of the CAA demonstrate
Congress' intent to focus attention directly on the problem of
pollution from a specific set of existing sources (64 FR 35737). The
CAA requires that any of these existing sources ``which, as determined
by the State, emits any air pollutant which may reasonably be
anticipated to cause or contribute to any impairment of visibility [in
a Class I area],'' shall install the best available retrofit technology
for controlling emissions.\3\ In determining BART, the CAA requires the
State to consider several factors that are set forth in section
169(g)(2) of the CAA, including the degree of improvement in visibility
which may reasonably result from the use of such technology.
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\3\ CAA sections 169A(b)(2) and (g)(7).
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The regional haze rule addresses visibility impairment resulting
from emissions from a multitude of sources located across a wide
geographic area. Because the problem of regional haze is caused in
large part by the long-range transport of emissions from multiple
sources, and for certain technical and other reasons explained in that
rulemaking, we had adopted an approach that required States to look at
the contribution of all BART sources to the problem of regional haze in
determining both applicability and the appropriate level of control.
Specifically, we had concluded that if a source potentially subject to
BART is located within an upwind area from which pollutants may be
transported downwind to a Class I area, that source ``may reasonably be
anticipated to cause or contribute'' to visibility impairment in the
Class I area. Similarly, we had also concluded that in weighing the
factors set forth in the statute for determining BART, the States
should consider the collective impact of BART sources on visibility. In
particular, in considering the degree of visibility improvement that
could reasonably be anticipated to result from the use of such
technology, we stated that the State should consider the degree of
improvement in visibility that would result from the cumulative impact
of applying controls to all sources subject to BART. We had concluded
that the States should use this analysis to determine the appropriate
BART emission limitations for specific sources.\4\
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\4\ See 66 FR at 35737-35743 for a discussion of the rationale
for the BART requirements in the 1999 regional haze rule.
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In American Corn Growers v. EPA, industry petitioners challenged
EPA's interpretation of both these aspects of the BART determination
process and raised other challenges to the rule. The court in American
Corn Growers concluded that the BART provisions in the 1999 regional
haze rule were inconsistent with the provisions in the CAA ``giving the
states broad authority over BART determinations.'' 291 F.3d at 8.
Specifically, with respect to the test for determining whether a source
is subject to BART, the court held that the
[[Page 39106]]
method that EPA had prescribed for determining which eligible sources
are subject to BART illegally constrained the authority Congress had
conferred on the States. Id. The court did not decide whether the
general collective contribution approach to determining BART
applicability was necessarily inconsistent with the CAA. Id. at 9.
Rather, the court stated that ``[i]f the [regional haze rule] contained
some kind of a mechanism by which a state could exempt a BART-eligible
source on the basis of an individualized contribution determination,
then perhaps the plain meaning of the Act would not be violated. But
the [regional haze rule] contains no such mechanism.'' Id. at 12.
The court in American Corn Growers also found that our
interpretation of the CAA requiring the States to consider the degree
of improvement in visibility that would result from the cumulative
impact of applying controls in determining BART was inconsistent with
the language of the Act. 291 F.3d at 8. Based on its review of the
statute, the court concluded that the five statutory factors in section
169A(g)(2) ``were meant to be considered together by the states.'' Id.
at 6.
C. Changes in Response to American Corn Growers
Today's rule responds to the American Corn Growers court's decision
on the BART provisions by including changes to the regional haze rule
at 40 CFR 51.308, and by finalizing changes to the BART guidelines.
This section outlines the changes to the regional haze rule due to the
court's remand. It also explains the minor change we are making to the
section of the regulation governing the use of the 1980 BART guidelines
when conducting BART analyses for certain power plants for reasonably
attributable (i.e., localized) visibility impairment.
1. Determination of Which Sources Are Subject to BART
Today's action addresses the American Corn Growers court's vacature
of the requirement in the regional haze rule requiring States to assess
visibility impacts on a cumulative basis in determining which sources
are subject to BART. Because this requirement was found only in the
preamble to the 1999 regional haze rule (see 291 F.3d at 6, citing 64
FR 35741), no changes to the regulations are required. Instead, this
issue is addressed in the BART guidelines, which provide States with
appropriate techniques and methods for determining which BART-eligible
sources ``may reasonably be anticipated to cause or contribute to any
impairment of visibility in any mandatory Class I Federal area.'' These
processes, to address the holding of American Corn Growers by
eliminating the previous constraint on State discretion, are explained
in further detail in sections II.D. and III below.
2. Consideration of Anticipated Visibility Improvements in BART
Determinations
Pursuant to the remand in American Corn Growers, we are amending
the regional haze rule to require the States to consider the degree of
visibility improvement resulting from a source's installation and
operation of retrofit technology, along with the other statutory
factors set out in CAA section 169A(g)(2), when making a BART
determination. This has been accomplished by listing the visibility
improvement factor with the other statutory BART determination factors
in 40 CFR 51.308(e)(1)(A), so that States will be required to consider
all five factors, including visibility impacts, on an individual source
basis when making each individual source BART determination.
D. Center for Energy and Economic Development v. EPA
After the May 2004 reproposal of the BART guidelines, the D.C.
Circuit decided another case where BART provisions were at issue,
Center for Energy and Economic Development v. EPA, 398 F.3d 653, 2005
(``CEED''). In this case, the court granted a petition challenging
provisions of the regional haze rule governing the optional emissions
trading program for certain western States and Tribes (the ``WRAP Annex
Rule'').
The court in CEED affirmed our interpretation of CAA section
169A(b)(2) as allowing for non-BART alternatives where those
alternatives are demonstrated to make greater progress than BART.
(CEED, slip. op. at 13). The court, however, took issue with provisions
of the regional haze rule governing the methodology of that
demonstration. Specifically, 40 CFR 51.308(e)(2) requires that
visibility improvements under source-specific BART--the benchmark for
comparison to the alternative program--be estimated based on the
application of BART controls to all sources subject to BART. (This
section was incorporated into the WRAP Annex rule by reference at 40
CFR 51.309(f)). The court held that we could not require this type of
group BART approach--vacated in American Corn Growers in a source-
specific BART context--even in a program in which State participation
was wholly optional.
The BART guidelines as proposed in May 2004 contained a section
offering guidance to States choosing to address their BART-eligible
sources under the alternative strategy provided for in 40 CFR
51.308(e)(2). This guidance included criteria for demonstrating that
the alternative program achieves greater progress towards eliminating
visibility impairment than would BART.
In light of the D.C. Circuit's decision in CEED, we have not
included the portion of the proposed BART guidelines addressing
alternative programs in today's rulemaking. We remain committed to
providing States with the flexibility to address BART through
alternative means, and we note again that our authority to do so was
upheld in CEED. Therefore, we intend to revise the provisions of the
regional haze rule governing such alternatives and provide any
additional guidance needed in a subsequent rulemaking conducted as
expeditiously as practicable.
E. Relationship Between BART and the Clean Air Interstate Rule (CAIR)
On March 10, 2005, EPA issued the Clean Air Interstate Rule (CAIR),
requiring reductions in emissions of sulfur dioxide (SO2)
and nitrogen oxides (NOX) in 28 eastern States and the
District of Columbia. When fully implemented, CAIR will reduce
SO2 emissions in these states by over 70 percent and
NOX emissions by over 60 percent from 2003 levels. The CAIR
imposes specified emissions reduction requirements on each affected
State, and establishes an EPA-administered cap and trade program for
EGUs in which States may participate as a means to meet these
requirements. The relationship between BART and the Clean Air
Interstate Rule (CAIR) is discussed in section IV. below.
F. Overview of the BART Process
The process of establishing BART emission limitations can be
logically broken down into three steps: First, States identify those
sources which meet the definition of ``BART-eligible source'' set forth
in 40 CFR 51.301. Second, States determine whether such sources
``emit[] any air pollutant which may reasonably be anticipated to cause
or contribute to any impairment of visibility [in a Class I area.]'' A
source which fits this description is ``subject to BART.'' Third, for
each source subject to BART, States then identify the appropriate type
and the level of control for reducing emissions.
[[Page 39107]]
Identifying BART-eligible sources. The CAA defines BART-eligible
sources as those sources which fall within one of 26 specific source
categories, were built during the 15-year window of time from 1962 to
1977, and have potential emissions greater than 250 tons per year. The
remand did not address the step of identifying BART-eligible sources,
which is conceptually the simplest of the three steps.
Sources reasonably anticipated to cause or contribute to visibility
impairment (sources subject to BART). As we noted in the preamble to
the 1999 regional haze rule, defining the individual contributions of
specific sources of the problem of regional haze can be time-consuming
and expensive. Moreover, Congress established a very low threshold in
the CAA for determining whether a source is subject to BART. We are
accordingly finalizing several approaches for States for making the
determination of whether a source ``emits any pollutants which may
reasonably be anticipated to cause or contribute to any visibility
impairment.'' Certain of these approaches would allow States to avoid
undertaking unnecessary and costly studies of an individual source's
contribution to haze by allowing States to adopt more streamlined
processes for determining whether, or which, BART-eligible sources are
subject to BART.
In 1999, we adopted an applicability test that looked to the
collective contribution of emissions from an area. In particular, we
stated that if ``a State should find that a BART-eligible source is
`reasonably anticipated to cause or contribute' to regional haze if it
can be shown that the source emits pollutants within a geographic area
from which pollutants can be emitted and transported downwind to a
Class I area.'' \5\ States certainly have the discretion to consider
that all BART-eligible sources within the State are ``reasonably
anticipated to cause or contribute'' to some degree of visibility
impairment in a Class I area.
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\5\ 64 FR 335740, July 1, 1999. The regional haze rule discusses
at length why we believe that States should draw this conclusion. 64
FR at 35739-35740.
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This is consistent with the American Corn Growers court's decision.
As previously noted, the court's concern with our original approach
governing BART applicability determinations was that it would have
``tie[d] the states' hands and force[d] them to require BART controls
at sources without any empirical evidence of the particular source's
contribution to visibility impairment.'' 291 F.3d at 8. By the same
rationale, we believe it would be an impermissible constraint of State
authority for the EPA to force States to conduct individualized
analyses in order to determine that a BART-eligible source ``emits any
air pollutant which may reasonably be anticipated to cause or
contribute to any impairment of visibility in any [Class I] area.'' \6\
American Corn Growers did not decide whether consideration of
visibility impact on a cumulative basis would be invalid in all
circumstances. 291 F.3d at 9. Given the court's emphasis on the
importance of the role of the States in making BART determinations, we
believe that a State's decision to use a cumulative analysis at the
eligibility stage is consistent with the CAA and the findings of the
D.C. Circuit.
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\6\ CAA section 169A(b)(2)(A).
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We believe a State may conclude that all BART-eligible sources
within the State are subject to BART.\7\ Any potential for inequity
towards sources could be addressed at the BART determination stage,
which contains an individualized consideration of a source's
contribution in establishing BART emission limits.
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\7\ See 64 FR at 35714, 35721; see also Supporting Information
for Proposed Applicability of Regional Haze Regulations, Memorandum
by Rich Damberg to Docket A-95-38, U.S. Environmental Protection
Agency, Office of Air Quality Planning and Standards, July 29, 1997.
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States also have the option of performing an analysis to show that
the full group of BART-eligible sources in a State cumulatively may not
be reasonably anticipated to cause or contribute to any visibility
impairment in Class I areas. We anticipate that in most, if not all
States, the BART-eligible sources are likely to cause or contribute to
some visibility impairment in Class I areas. However, it is possible
that using a cumulative approach, a State could show that its BART
sources do not pose a problem.
Finally, States may consider the individualized contribution of a
BART-eligible source to determine whether a specific source is subject
to BART. Specifically, States may choose to undertake an analysis of
each BART-eligible source in the State in considering whether each such
source meets the test set forth in the CAA of ``emit[ting] any air
pollutant which may reasonably be anticipated to cause or contribute to
any impairment of visibility in any [Class I] area.'' Alternatively,
States may choose to presume that all BART-eligible sources within the
State meet this applicability test, but provide sources with the
ability to demonstrate on a case by case basis that this is not the
case. Either approach appears consistent with the D.C. Circuit's
statement that a collective contribution approach may be appropriate so
long as the States are allowed to exempt sources on the basis of an
individualized contribution determination. 291 F.3d at 8.
Today's guidelines include different options States can use to
assess whether source should be subject to BART. States need to
determine whether to make BART determinations for all of their BART-
eligible sources, or to consider exempting some of them from BART
because they may not reasonably be anticipated to cause or contribute
to any visibility impairment in a Class I area. For assessing the
impact of BART-eligible sources on nearby Class I areas, we are
including a process whereby the States would use an air quality model
able to estimate a single source's contribution to visibility
impairment and a different process whereby States could exempt groups
of sources with common characteristics based on representative model
plant analyses. Finally, States may use cumulative modeling to show
that no sources in a State are subject to BART.
The BART determination. The State must determine the appropriate
level of BART control for each source subject to BART. Section
169A(g)(7) of the CAA requires States to consider the following factors
in making BART determinations: (1) The costs of compliance, (2) the
energy and nonair quality environmental impacts of compliance, (3) any
existing pollution control technology in use at the source, (4) the
remaining useful life of the source, and (5) the degree of improvement
in visibility which may reasonably be anticipated to result from the
use of such technology. The remand did not address the first four steps
of the BART determination. The remand did address the final step,
mandating that we must permit States to take into account the degree of
improvement in visibility that would result from imposition of BART on
each individual source when deciding on particular controls.
The first four factors are somewhat similar to the engineering
analysis in the original BART guidelines proposed in 2001 and
reproposed in 2004. The BART guidelines also contains a detailed
discussion of available and cost-effective controls for reducing
SO2 and NOX emissions from large coal-fired
electric generating units (EGUs).
For assessing the fifth factor, the degree of improvement in
visibility from various BART control options, the States may run
CALPUFF or another appropriate dispersion model to predict visibility
impacts. Scenarios would be
[[Page 39108]]
run for the pre-controlled and post-controlled emission rates for each
of the BART control options under review. The maximum 24-hour emission
rates would be modeled for a period of three or five years of
meteorological data. States have the flexibility to develop their own
methods to evaluate model results.
III. Detailed Discussion of the Final BART Guidelines
A. Introduction
In this section of the preamble, we discuss changes or
clarifications to the reproposed BART guidelines. Where relevant, we
also respond to comments received during the comment period on the 2001
proposal. For each provision of the guidelines that we are changing or
clarifying, we provide discussion of, as appropriate:
--Background information,
--How the provision was addressed in the May 2004 reproposal (and in
the 2001 proposal, if different from the reproposal),
--A summary of comments received on the provision, either from the May
2004 reproposal, from the July 2001 proposal, or from both, and
--The changes or clarifications that we are finalizing and the reasons
for these changes or clarifications.
B. Scope of the Rule--Whether To Require States To Follow the
Guidelines for All BART Sources
Background. Section 169A(b)(1) of the CAA requires EPA to issue
regulations to provide guidelines to States on the implementation of
the visibility program. In addition, the last sentence of section
169A(b) states:
In the case of a fossil-fuel fired generating powerplant having
a capacity in excess of 750 megawatts, the emission limitations
required under this paragraph shall be determined pursuant to
guidelines, promulgated by the Administrator under paragraph (1).
This statutory requirement clearly requires us to promulgate BART
guidelines that the States must follow in establishing BART emission
limitations for power plants with a total capacity exceeding the 750
megawatt cutoff. The statute is less clear regarding the import of the
guidelines for sources other than 750 megawatt power plants.
Proposed rules. Both the 2001 proposal and the 2004 reproposal
included a requirement for States to follow the procedures set out in
the guidelines in determining BART for sources in all of the 26 listed
BART categories. The 2001 proposal requested comment on whether the
regional haze rule should: (1) Require the use of the guidelines only
for 750 megawatt utilities, with the guidelines applying as guidance
for the remaining categories, or (2) require the use of the guidelines
for all of the affected source categories.
Comments. We received comments on this issue in both 2001 and 2004.
Comments varied widely on whether we can or should require the use of
the guidelines for all of the affected source categories.
Comments from State, local and tribal air quality agencies
generally supported our proposal to require the use of the guidelines
for all of the source categories. These comments cited a need for
national consistency in the application of the BART requirement across
the source categories, and from State to State. One State agency
commenter questioned our legal authority to require the use of the
guidelines for all source categories; and several State agency
commenters, while supporting the proposal, requested that we provide
clarification of the legal authority for requiring the States to use
the guidelines in establishing BART emission limitations for all
categories.
Comments from the utility industry, from various manufacturing
trade groups, and from individual companies were critical of the
proposal to require States to follow the guidelines generally. Many
commenters also argued that EPA lacked the authority to issue
guidelines for any industrial category other than 750 megawatt
powerplants, whether the use of such guidelines were mandatory or not.
Other commenters stated that the language in the CAA clearly restricts
the scope of mandatory guidelines to larger powerplants. The commenters
cited the legislative history of the 1977 Clean Air Act amendments in
support of this position, and frequently claimed that requiring the
guidelines for all 26 categories of sources would deprive States of
flexibility in implementing the program.
Comments from environmental organizations and the general public
supported the approach in the proposed rule and stated that EPA is
obligated to establish regional haze BART guidelines by rulemaking for
all 26 categories of stationary sources. Environmental organization
comments noted that while Congress expressed a particular concern for
750 MW powerplants, this added emphasis on one sector does not change
requirements in the Act for all BART-eligible sources. Accordingly,
these commenters believed that we should not construe a special
emphasis on powerplants as a restriction on our authority to require
use of the guidelines for all categories.
Final rule. The CAA and the relevant legislative history make clear
that EPA has the authority and obligation to publish mandatory
guidelines for powerplants exceeding 750 megawatts. As previously
noted, Congress in section 169A(b) of the CAA expressly provided that
emission limitations for powerplants larger than 750 megawatts ``shall
be determined pursuant to guidelines promulgated by the
Administrator.'' (Emphasis added). This unambiguous language leaves
little room to dispute that the guidelines EPA is required to
promulgate must be used by States when making BART determinations for
this class of sources.
Having carefully considered the comments and further reviewed the
CAA and the legislative history, we have concluded that it would not be
appropriate for EPA to require States to use the guidelines in making
BART determinations for other categories of sources. The better reading
of the Act indicates that Congress intended the guidelines to be
mandatory only with respect to 750 megawatt powerplants. Thus, while we
acknowledge the State agency comments and the policy reasons support
consistency across States, we are not requiring States to use the BART
guideline for these other categories. In response to State concerns
about equitable application of the BART requirement to source owners
with similar sources in different States, we do encourage States to
follow the guidelines for all source categories but are not requiring
States to do so. States should view the guidelines as helpful guidance
for these other categories.
We disagree with comments that the CAA and the legislative history
prohibit us from issuing guidance for other source categories. As the
guidelines make clear, States are not required to follow the approach
in the guidelines for sources other than 750 megawatt powerplants. As
such, although we believe that the guidelines provide useful advice in
implementing the BART provisions of the regional haze rule, we do not
believe that they hamper State discretion in making BART
determinations.
C. How To Identify BART-Eligible Sources
Section II of the BART guidelines contains a step-by-step process
for identifying stiationary sources that are ``BART-eligible'' under
the definitions in the regional haze rule. The four basic steps are:
Step 1: Identify the emission units in the BART categories.
Step 2: Identify the start-up dates of those emission units.
[[Page 39109]]
Step 3: Compare the potential emissions from units identified in
Steps 1 and 2 to the 250 ton/year cutoff.
Step 4: Identify the emission units and pollutants that constitute
the BART-eligible source.
In this section of the preamble, we discuss some of the comments we
received on the steps in this process, and any changes we are making in
light of those comments.
Step 1: Identify the Emission Units in the BART Categories
The BART guidelines list the 26 source categories that the CAA uses
to describe the types of stationary sources that are BART-eligible.
Both proposals clarified the descriptions of particular source
categories.
Comments. The final rule addresses comments on the following source
categories. Some comments discussed below were submitted in response to
the 2001 propoosal and were not addressed in the reproposal; other
comments were submitted in response to the reproposal in 2004.
(1) ``Charcoal production facilities.'' We received comments in
2001 from two industry trade groups requesting that the final
guidelines explicitly exclude ``low-emission'' charcoal production
facilities from BART. These comments cited a 1975 study considered by
Congress in development of the BART category list in the 1977 CAA
amendments. This 1975 study noted that some charcoal production
facilities have much higher emissions factors (i.e., 352 pounds of PM
per ton of charcoal produced versus 20 to 25 pounds of PM per ton of
charcoal produced). Accordingly, the comments asserted that the intent
of Congress in the 1977 CAA amendments was to provide incentives for
higher-emitting facilities to reduce their emissions, rather than to
make the entire category BART-eligible.
(2) ``Chemical process plants.'' In 2001 a trade group representing
the pharmaceutical industry requested that we determine in the
guidelines that the term ``chemical process plants'' does not include
pharmaceutical plants.
(3) ``Primary aluminum ore reduction.'' Comments from the aluminum
industry in 2001 noted that not all emissions units at these facilities
are necessarily involved in ``primary ore reduction.'' Thus, the
comments recommended that we clarify that contiguous sources that are
not related to primary aluminum ore reduction, such as fabricating
facilities and ingot operations, are not BART-eligible. Further, the
comments recommended that we use definitions in the NSPS for primary
aluminum plants to describe the BART-eligible emissions units.
(4) ``Fossil-fuel fired steam electric plants of more than 250
million Btu/hour heat input.'' The 2004 reproposal contained the
clarification, requested by commenters, that this source category
refers only to those fossil-fuel fired steam electric plants that
generate electricity for sale. One commenter objected to this
clarification on the basis that emissions from co-generators would be
excluded; many other commenters supported the clarification. Another
commenter requested that we also clarify that this category includes
only those steam electric plants that burn greater than 50 percent
fossil fuel, in order to be consistent with the definition of fossil-
fuel boilers proposed in the guidelines. Other commenters requested
that we clarify whether the definition includes units which are located
at a steam electric plant, but which themselves are not in any of the
26 BART source categories, such as simple cycle turbines, emergency
diesel engines, and reciprocating internal combustion engines (RICE).
Several commenters opined that the category should exclude combined
cycle units with heat recovery steam generators that lack auxiliary
firing, arguing that these units should count as simple cycle turbines.
These commenters pointed to other EPA regulatory programs that treat
combined cycle units with supplemental firing differently from combined
cycle units without supplemental firing. They argued that we should
only consider a combined cycle unit to be a ``steam electric plant'' if
it has supplemental firing.
(5) ``Fossil-fuel boilers of more than 250 million Btu/hour heat
input.'' The 2004 reproposal clarified that this category should be
read as including only those boilers individually greater than 250
million Btu/hour heat input. We received many comments on this
interpretation, both in favor and opposed. Those favoring this
interpretation (generally industry commenters) cited the implementation
burden that including smaller boilers would pose, the high cost-
effectiveness of controlling smaller boilers, and the relatively
smaller impact on regional haze that smaller boilers would pose. They
also noted that this interpretation is most consistent with definitions
in the NOX SIP call and new source performance standards
(NSPS).
Commenters opposing this interpretation (environmental groups, one
state, and one regional planning organization) noted that regarding all
boilers, irrespective of size, as BART-eligible so long as the
aggregate heat input exceeds 250 million Btu/hour is more consistent
with the definition of stationary source under the Prevention of
Significant Deterioration (PSD) program. These commenters noted that
under the CAA, BART and PSD are complementary programs aimed at
regulating the same source categories; either one or the other applies
depending upon when the source was constructed.
The 2004 reproposal also clarified that if a boiler smaller than
250 million Btu/hour heat input is an integral part of an industrial
process in a BART source category other than electric utilities, then
the boiler should be considered part of the BART-eligible source in
that category. Under these circumstances, the boiler, as part of the
BART-eligible source, should be considered for emission control. Some
commenters opposed this interpretation, asserting that it would result
in an ``arbitrary and capricious'' inconsistency, in that some smaller
boilers would be BART-eligible, and others would not. These commenters
also noted that these boilers could be included in regional haze SIPs
as necessary for making ``reasonable progress'' toward CAA visibility
goals, even if they are not considered to be BART-eligible.
Final rule. After considering the comments, we have made the
following determinations on the definitions of the following source
categories:
(1) ``Charcoal production facilities.'' We believe that in using
the term ``charcoal production facilities'' Congress intended to
encompass all types of charcoal production facilities. We do not agree
with comments that any inferences can necessarily be made regarding the
presence of different PM emission factors for different types of
charcoal production facilities in the 1975 report. For example, if
Congress only intended to regulate a subset of the charcoal production
industry, then we believe Congress could have easily indicated this in
the source category title, as was done for ``kraft pulp mills'' and for
``coal cleaning plants (thermal dryers).'' We also note that it is more
likely that plants in the charcoal production industry with lower
emission factors have emissions that are less than the 250 tons per
year cutoff for BART eligibility.
(2) ``Chemical process plants.'' We believe that there is a clear
precedent to include pharmaceutical manufacturing operations as
``chemical process plants.'' In the standard industrial classification
(SIC) system, pharmaceutical operations are generally
[[Page 39110]]
in SIC codes 2833 and 2834, which are a subset of 2-digit category 28
``Chemical and Allied products.'' Similarly, in the new North American
Industrial Classification Codes (NAICS), pharmaceutical manufacturing
is codes 32541 and 32542, which is a subset of the ``chemical
manufacturing subsector'' which is code 325. Accordingly, in the PSD
program, pharmaceutical plants have been treated as ``chemical process
plants.'' The commenter is correct in noting that EPA has consistently
distinguished between chemical manufacturing and pharmaceutical
manufacturing. Examples where different standards or guidelines are
established included control technique guideline (CTG) documents, NSPS
standards under section 111 of the CAA, and, most recently, maximum
achievable control technology (MACT) standards under section 112 of the
CAA. We do not agree that these differentiations for emissions
standards necessarily require differentiation for purposes of
determining BART eligibility. Therefore we believe pharmaceuticals
should not be excluded from BART. However, we expect that because of
the MACT standards, there is a very low probability that BART
determinations will lead to further control requirements from chemical
production processes at pharmaceutical plants.
(3) ``Primary aluminum ore reduction.'' We agree with commenters
that BART-eligible units in this source category should be defined
consistently with the NSPS definition for primary aluminum ore
reduction. Therefore we have added a clarification to that effect in
the final BART guidelines. We note that this definition is also
consistent with the definition at 40 CFR 63.840, which establishes
applicability for this source category for the MACT program.
(4) ``Fossil-fuel fired steam electric plants of more than 250
million Btu/hour heat input.'' We have retained the clarification that
this source category refers only to those fossil-fuel fired steam
electric plants that generate electricity for sale. We believe that
this clarification helps to distinguish those plants that are electric
utilities from plants in other industrial categories. We also believe
that while large co-generators would be excluded from the fossil-fuel
fired steam electric plant source category, most large co-generators
will be BART-eligible under the fossil-fuel fired boilers source
category.
We do not believe it makes sense for this category to include only
those steam electric plants that burn greater than 50 percent fossil
fuel. We do not believe that a boiler should be excluded from BART
review simply because it is located at a plant which burns less than 50
percent fossil fuel. Emissions from any such boiler could be a
significant contributor to regional haze, and as such, we believe that
each fossil-fuel fired boiler merits a BART review.
We do wish to clarify that units which are located at a steam
electric plant, but which themselves are not in any of the 26 BART
source categories, should not be considered to be BART-eligible units.
We believe that Congress intended that BART review be focused on units
in the source categories it delineated. This interepretation is most
consistent with the definition of BART-eligible source as we have
explained it elsewhere in this preamble in reference to whether entire
plants are included if only some units at the plant meet the statutory
criteria.
Finally, we believe that all combined cycle units are included in
the definition of fossil fuel fired steam electric plant, regardless of
whether the combined cycle unit's heat recovery steam generator lacks
auxilliary firing. Commenters are correct that some EPA programs have
treated combined cycle units with supplemental firing differently from
combined cycle units without supplemental firing. However, while some
EPA programs do not consider a unit to be a combined cycle unit unless
it contains supplemental firing, the definition at issue here is the
definition of fossil-fuel fired steam electric plant, not fossil-fuel
fired unit. The CAA defines both ``stationary source'' (for visibility
purposes) and ``major emitting facility'' (for PSD purposes) to include
``fossil fuel fired steam electric plants.'' In previous guidance for
PSD, we have explained that combined cycle gas turbines do fall within
the category of ``fossil-fuel fired steam electric plants.'' \8\
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\8\ See http://www.epa.gov/Region7/programs/artrd/air/nsr/nsrmemos/turbines.pdf
.
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(5) ``Fossil-fuel boilers of more than 250 million Btu/hour heat
input.'' We have decided to retain the interpretation that this
category should be read as including only those boilers individually
greater than 250 million Btu/hour heat input. We agree with commenters
who noted that including smaller boilers would pose considerable
implementation burden. As noted in the 2004 reproposal notice, we do
not believe that this interpretation is likely to have a substantial
impact. Because smaller boilers are generally less cost-effective to
control, we believe that BART review would be unlikely to result in a
significant amount of control on these boilers.
We are also retaining the clarification that if a boiler smaller
than 250 million Btu/hour heat input is an integral part of an
industrial process in a BART source category other than electric
utilities, then the boiler should be considered part of the BART-
eligible source in that category. (By ``integral to the process'', we
mean that the process uses any by-product of the boiler, or vice-versa.
We have added this clarification to the definition in the BART
guidelines.) We believe that if a State is already considering a BART-
eligible industrial process for control, and a boiler is integrated
into that process, it makes common sense not to prematurely rule out
control options any of the emissions from that process as a whole.
(Note that a boiler which is not integral, but is simply attached to a
plant, should not be included.) For example, Kraft pulp mills may have
boilers that are not serving the energy infrastructure of the plant but
typically are serving a process directly by using the waste liquor from
the process. Including such a boiler in consideration of control
options for the process adds minimal additional burden while leaving
maximum discretion to the State in determining BART for the process as
a whole.
We are also clarifying today that we have determined that this
category should include all individual boilers of greater than 250
million Btu/hour heat input burning any amount of fossil fuel, as
opposed to only those boilers that burn greater than 50 percent fossil
fuel. We believe that it is quite possible that boilers of this size
could contribute to regional haze in a Class I area even if they burn
less than 50 percent fossil fuel. Therefore we believe that each fossil
fuel-fired boiler merits a BART review.
Step 2: Identify the Start-up Dates of Those Emission Units
Background. BART applies only to a major stationary source which
``was in existence on August 7, 1977 but which has not been in
operation for more than fifteen years as of such date.'' The visibility
regulations define ``in existence'' and ``in operation'' in 40 CFR
51.301. Under these regulations, promulgated in 1980, ``in existence''
means
that the owner or operator has obtained all necessary
preconstruction approvals or permits * * * and either has (1) begun,
or caused to begin, a continuous program of physical on-site
construction of the facility or (2) entered into binding agreements
or contractual obligations.
[[Page 39111]]
The term ``in operation'' means engaged in activity related to the
primary design function of the source.
Step 2 also addresses the treatment of ``reconstructions'' and
``modifications.'' Under the definition of BART-eligible facility,
sources which were in operation before 1962 but reconstructed during
the 1962 to 1977 time period are treated as new sources as of the time
of reconstruction.\9\ The same policies and procedures for identifying
reconstructed ``affected facilities'' under the NSPS are used to
determine whether a source has been reconstructed for purposes of the
BART requirements. ``Modifications'' under the CAA refers to physical
change or change in the method of operation at a source which has led
to an increase in emissions. In the proposed BART guidelines, we stated
that the best interpretation of the visibility provisions is that a
modification to a source does not change an emission's unit
construction date for purposes of BART applicability. We requested
comment on an alternative interpretation that we believed would be more
difficult to implement. Under this approach, sources built before 1962
but modified during the 1962 to 1977 time frame would be considered
``new'' at the time of modification.
---------------------------------------------------------------------------
\9\ However, sources reconstructed after 1977, which
reconstruction had gone through NSR/PSD permitting, are not BART-
eligible.
---------------------------------------------------------------------------
Comments. We received comments in 2001 and 2004 on the discussion
in the guideline of the term ``in existence.'' These comments were
critical of our statement in the guidelines that sources which had
``commenced construction,'' that is, those which had entered into
binding contracts, would be considered to be in existence, even if
actual operations did not begin until after the August 7, 1977 cutoff
date. These commenters asserted that Congress did not intend to treat a
source as ``existing'' in 1977 if it was not yet built.
Other commenters interpreted the proposed guidelines as expanding
the definition of BART-eligible sources by requiring States to find
that all emission units at a facility are BART-eligible if one part of
the facility was built within the 1962-1977 time period. Other comments
did not suggest that we had already expanded the definition in the
proposed guidelines, but did suggest that we should expand the
definition in that way in the final guidelines. Some commenters noted
that there was a degree of confusion in the regulated community on
whether the proposed guidelines were requiring BART for all units at a
power plant, including those that were in operation before August 7,
1962, if these units are co-located with one or more units that were
put in place within the 1962-1977 time period. These commenters
requested that we clarify that such pre-1962 units would not be BART-
eligible.
Some commenters asserted that our proposed approach is unworkable,
because the approach requires States to identify all emissions units
put in place between the 1962 and 1977. Some of these commenters
asserted that Congress intended that BART would apply only if entire
plants satisfy the statutory criteria. These comments suggested that
BART should apply only if an entire plant that is one of the 26 listed
source category types had been placed in operation at a discrete point
within the 15 year time period for BART eligibility. These commenters
asserted that our proposed guidelines, which involved the
identification and aggregation of individual emission units within the
1962-1977 time period, were inconsistent with Congress' intent. Other
comments suggested that EPA could improve implementation of the program
by covering discrete projects rather than individual emissions units. A
few commenters suggested that for purposes of identifying such discrete
projects, we consider using the term ``process or production unit''
that we used in hazardous air pollutant regulations under CAA section
112(g).
One commenter requested that the guidelines clarify that emissions
from ``linked'' emission units should not be considered in determining
BART eligibility. That is, even if changes in emissions from one unit
could affect the emissions from a ``linked'' unit that was not put in
place within the 1962-1977 time period, that would not affect whether
the ``linked'' unit was BART-eligible. Another commenter suggested that
the approach set forth in the guidelines for identifying BART-eligible
sources is inappropriate because the particular set of units identified
as BART-eligible will not necessarily ``provide a reasonable and
logical platform for the installation of controls.''
Other commenters stated that facilities that had been modified
after 1977 should not be included in the pool of sources subject to
BART. Such facilities, it was argued, already meet the BART
requirements because of the controls installed to meet the requirements
of PSD, NSR, or the NSPS.
Final rule. We disagree with the comments recommending that we
interpret the term ``in existence'' to refer to sources that are in
actual operation. The discussion of this term in Step 2 is based on the
regulatory definition which has been in place since 1980. The
guidelines reiterate this definition and provide examples of its
application. Interpreting the term ``in existence'' as suggested by
commenters would not be consistent with the plain language of the
regulations.
In the 2001 and 2004 proposed guidelines, we noted that ``the term
`in existence' means the same thing as the term `commence construction'
as that term is used in the PSD regulations.'' Commenters were critical
of this statement, claiming that EPA was unlawfully reinterpreting
section 169A in the guidelines. The statement in Step 2 of guidelines,
however, is not a reinterpretation of the term ``in existence,'' but
merely a statement noting that the definitions used in the visibility
regulations and the PSD regulations are essentially identical.
To the extent that commenters are claiming that the existing
regulatory definition of ``in existence'' is unlawful, EPA's
interpretation of this term in promulgating the 1980 regulations was a
reasonable one. First, it is worth noting that the regulations adopting
this interpretation of the term ``in existence'' were in effect in 1990
and implicitly endorsed by Congress in its 1990 amendments to the
CAA.\10\ Moreover, the definition at issue accurately reflects
Congress' intent that the BART provision apply to sources which had
been ``grandfathered'' from the new source review permit requirements
in parts C and D of title I of the CAA. For all the above reasons, we
are neither revising the regional haze regulations to change the
definition of ``in existence,'' nor adopting a strained interpretation
of the regulation in the guidelines.
---------------------------------------------------------------------------
\10\ See CAA section 193.
---------------------------------------------------------------------------
We agree with commenters that the definition of ``BART-eligible
source'' does not require States to find that all emission units at a
facility are subject to the requirement of the BART provisions if only
one part of the facility was built within the 1962-1977 time period. We
received comments on this issue in 2001 and clarified in 2004 that the
BART guidelines do not direct States to find that all boilers at a
facility are BART-eligible if one or more boilers at the facility were
put in place during the relevant time period. Under Step 2 of the
process for identifying BART-eligible sources set out in the
guidelines, States are required to identify only those boilers that
were put in place between 1962 and 1977. As explained in the preamble
to the 2004 reproposed guidelines, only these boilers are potentially
subject to BART.
[[Page 39112]]
We do not agree with those commenters claiming that Congress
clearly intended to apply BART only if an ``entire plant'' was put into
place between 1962 and 1977. Most of the BART source categories are
broad descriptions types of industrial facilities such as ``kraft pulp
mills,'' ``petroleum refineries'' or ``primary copper smelters.'' For
such source categories, the implication of commenters' argument would
that if any portion of the plant was in operation before August 7,
1962, then Congress intended to exempt the entire plant from BART. Such
an interpretation is problematic and inequitable. For example, under
this approach BART would not apply if a company chose to expand its
production by building a second production line at an existing line in
1965, but would apply if the same company chose to build the same
equipment at a greenfield site. Under the approach set forth in the
guidelines, such a production line would be treated similarly under
either set of facts. We do not believe that either the plain language
of the statute or the relevant legislative history indicate that
Congress intended for major-emitting sources of visibility-impairing
pollutants to be exempted from the BART requirements because a plant
contains some emission units that began operation before 1962.
Also, we disagree with the comment that modifications after 1977
should change an emissions' unit date of construction for purposes of
BART applicability. The commenter's suggestion that such sources
already meet BART requirements may be accurate, but does not provide a
basis for exempting the source from review. As we note in the
guideline, the review process will take into account the controls
already in place and the State may find that these controls are
consistent with BART.
We agree with the comments related to ``linked'' emission units.
The comment appears to address whether emissions from the ``linked''
units are considered in determining BART eligibility. In the
guidelines, we are focusing on only the emissions units that were put
in place during the 1962 to 1977 dates and the emissions from those
units. We agree that even if changes in emissions from one unit could
affect the emissions from a ``linked'' unit that was not put in place
within the 1962-1977 time period, this would not affect whether the
``linked'' unit was BART-eligible.
We disagree with commenters that the approach set forth in the
guidelines for identifying BART-eligible sources is inappropriate
because the particular set of units identified as BART-eligible will
not necessarily ``provide a reasonable and logical platform for the
installation of controls.'' We do not agree that this factor is
relevant to the identification of those emissions units which meet the
definition of BART-eligible source. Such factors are important in the
States' consideration of control strategies and options but do not
clearly relate to the first step of identifying those sources which
fall within one of 26 source categories, were built during the 15 year
window of time from 1962 to 1977, and have potential emissions of
greater than 250 tons per year. We do thus agree generally with the
commenter's recommendation of allowing States to consider the
particular history and control potential of units in determining BART,
but do not agree that it is relevant to the predicate question of
identifying the BART-eligible source.
Finally, the approach to identifying a ``BART-eligible source'' in
the guidelines is based on the definitions in the regional haze rule of
the relevant terms. For 750 MW power plants, States are required to
apply the definitions as set forth in the guidelines; for other
sources, States may adopt a different approach to the task of
identifying BART-eligible sources, so long as that approach is
consistent with the Act and the implementing regulations. In other
words, while the guidelines adopt an approach for large power plants
which involves the aggregation of all emissions units put into place
between 1962 and 1977, States have the flexibility to consider other
reasonable approaches to the question of identifying BART-eligible
sources for other source categories.
For 750 MW power plants, many of the issues identified by
commenters with the approach of looking at a facility on an emission
unit by emission unit basis do not exist. Unlike many types of
industrial processes, power plants consist generally of a discrete
number of very large emission units. For other types of facilities such
as kraft pulp mills or chemical process plants which may have many
small emission units that have undergone numerous changes, the
guidelines do not limit the ability of the States to approach the
question of identifying BART-eligible sources in ways which make sense
for the particular sources given their design and history.
Step 3: Compare the Potential Emissions to the 250 Ton/Yr Cutoff.
Background. Step 3 of the guidelines addresses the question of
whether the units identified in Steps 1 and 2 have emissions in excess
of the threshold for major sources set forth in section 169A(g)(7) of
the CAA. The guidelines pose the following questions to help the States
in determining whether the relevant emissions units have the potential
to emit in excess of the 250 tons per year threshold of any single
visibility-impairing pollutant:
(1) What pollutants should I address?
The 2001 proposed guidelines included the following list of
visibility-impairing pollutants: SO2, NOX,
particulate matter, volatile organic compounds (VOCs), and ammonia. We
proposed in 2001 and again in 2004 that States use PM10 as
the indicator for particulate matter. As explained in the guidelines,
there is no need to have separate 250 ton thresholds for
PM10 and PM2.5 because emissions of
PM10 include the components of PM2.5 as a subset.
In addition, because of various uncertainties associated with
regulating VOCs and ammonia, we requested comment in 2004 on the level
of discretion States should exercise in making BART determinations for
VOCs and took ammonia off the list of visibility-impairing pollutants.
In both proposals, we clarified that the 250 tons per year cutoff
applies to emissions on a pollutant by pollutant basis. In other words,
a source is subject to BART only if it emits at least 250 tons per year
of an individual visibility-impairing pollutant.
(2) What does the term ``potential'' emissions mean?
The proposed guidelines in 2001 and the reproposed guidelines in
2004 excerpt the definition of ``potential to emit'' from the
regulations at 40 CFR 51.301. As the definition makes clear, the
potential to emit of a source is calculated based on its capacity to
emit a pollutant taking into account its physical and operational
design. Under this definition, federally enforceable emission limits
may be taken into account in calculating a source's potential
emissions; however, emission limitations which are enforceable only by
State and local agencies, but not by EPA and citizens in Federal court,
cannot be used to limit a source's potential to emit for purposes of
the regional haze program.
(3) What is a ``stationary source?'
As explained above, States are required to make a BART
determination only for ``stationary sources'' of a certain size that
fall within one of 26 types of industrial categories listed in the
statute and that were built within a certain time frame. The regional
haze rule contains definitions that are relevant to the determination
of the emissions units that comprise a ``stationary source.'' First,
the regulations at 40 CFR 51.301
[[Page 39113]]
define ``stationary source'' as ``any building, structure, facility, or
installation which emits or may emit any air pollutant.'' Second, the
terms ``building, structure, or facility'' are defined in part based on
grouping pollutant-emitting activities by industrial category:
Building, structure, or facility means all of the pollutant-
emitting activities which belong to the same industrial grouping,
are located on one or more contiguous or adjacent properties, and
are under the control of the same person (or persons under common
control). Pollutant-emitting activities must be considered as part
of the same industrial grouping if they belong to the same Major
Group (i.e., which have the same two-digit code) as described in the
Standard Industrial Classification Manual, 1972 as amended by the
1977 Supplement (U.S. Government Printing Office stock numbers 4101-
0066 and 003-005-00176-0 respectively).
In the 2001 proposed guideline, we noted that support facilities,
i.e. facilities used to convey, store, or otherwise assist in the
production of the principal product, are considered to fall within the
same industrial grouping as the primary facility. To clarify this, in
2004 we proposed to add language to the guideline noting that emission
units at a plant, even if they are a ``support facility'' for purposes
of other programs, would not be subject to BART unless they were within
one of the 26 listed source categories and were built within the 1962
to 1977 time frame.
Discussion of ``What Pollutants Should I Address?''
Comments. PM10 as an indicator. Some comments questioned
the use of PM10 (which includes both coarse and fine
particulate matter) as the indicator for particulate matter. Commenters
noted that the coarse fraction, that is particulate matter between 10
and 2.5 micrograms in diameter, fundamentally differs compared to the
fine mass in how it interacts with light. Commenters suggested that
only the fine mass (PM2.5) component of particulate matter
is likely to contribute to visibility impairment. Accordingly, these
commenters recommended that the 250 ton cutoff for particulate matter
should be based upon emissions of PM2.5.
Ammonia. Many commenters addressed the exclusion of ammonia from
the list of visibility-impairing pollutants. A number of commenters,
primarily from industry but also from one state and one regional
planning organization, supported the exclusion of ammonia. These
commenters generally cited the complexity and variability of ammonia's
role in the formation of PM2.5 in the atmosphere, the
relative greater benefits of controlling NOX and
SO2, the uncertainties in the inventory of ammonia
emissions, and the inherent complexities of gauging the contribution of
potential ammonia reductions to improving visibility in Class I areas.
In addition, commenters noted that few, if any, point sources emit
ammonia in amounts that exceed the 250 ton per year threshold.
Other commenters, including a number of environmental groups and
several states, regional planning organizations, and industry
commenters, argued that ammonia should be included in the list of
visibility-impairing pollutants in the guidelines. In support of this
view, commenters cited evidence that ammonia is a known precursor to
PM2.5. One commenter noted that improvements are being made
to ammonia inventories and to the understanding of ammonia's role in
the formation of haze. Other commenters pointed to a National Park
Service (NPS) analysis of monitoring data that indicates that
visibility-impairment due to nitrate aerosol formation (to which
ammonia contributes) is of significant concern \11\ and to a 2003
direction to policy-makers from the North American Research Strategy
for Tropospheric Ozone (NARSTO) \12\ indicating that consideration of
control strategies needs to include ammonia in combination with other
precursors to particle formation. Many commenters also argued that EPA
should encourage or allow the States to consider ammonia in their
visibility protection plans, and noted that ammonia reductions could be
a cost-effective way to improve visibility under certain conditions.
---------------------------------------------------------------------------
\11\ See http://wrapair.org/forums/ioc/meetings/030728/index.html
(specifically presentation by John Vimont, National Park
Service).
\12\ NARSTO, Particulate Matter Assessment for Policy Makers: A
NARSTO Assessment. P. McMurry, M. Shepherd, and J. Vickery, eds.
Cambridge University Press, Cambridge, England (2004).
---------------------------------------------------------------------------
Volatile Organic Compounds (VOCs). Several commenters responded to
our request for comments on whether States should treat VOCs in urban
areas differently from VOCs in rural areas. Environmental groups and a
few States argued that the current state of scientific knowledge does
not support a differentiation between urban and rural sources of VOCs.
One environmental commenter cited evidence that organic aerosols are a
major constituent of visibility-reducing aerosols and that VOCs are
important precursors to the formation of secondary organic aerosols.
One commenter also stated that VOCs may play a particularly significant
role in particle formation in those rural areas with significant nearby
sources of NOX. Commenters also cited evidence that the
contribution of VOC to particle formation likely varies widely in
different areas of the country, and argued that States should retain
flexibility to address local VOC sources if they determine that those
sources are contributors of concern.
Several industry commenters stated that more focus should be placed
on controlling VOCs in urban rather than rural areas. A few commenters
from industry argued that VOCs in rural areas have not been shown to be
a significant contributor to particle formation, and should be excluded
from the list of pollutants to be addressed in the BART process. One
argued that VOCs should be excluded from BART entirely based upon
uncertainties in the current state of knowledge, and a few argued that
VOCs from both power plants and rural sources should be excluded from
BART, based on low emissions and the cost of controls. One regional
planning organization requested that EPA clarify the definitions of
``urban'' and ``rural'' areas.
Final rule. PM10 as an indicator. While it is always
necessary to assess PM2.5 impacts, we agree with commenters
who stated that the coarse fraction is less efficient at light
scattering than fine particles, there is ample evidence that the coarse
fraction does contribute to visibility impairment.\13\ For example,
standard methods for calculating reconstructed light extinction
routinely include a calculation for the contribution to light
extinction from the coarse fraction, an implicit recognition that these
particles contribute measurably to visibility impairment.\14\ We do
recognize that coarse PM is likely to contribute more to regional haze
in arid areas than humid areas. We believe that, as the Grand Canyon
Visibility Transport Commission (GCTVC) recognized,\15\ States in the
arid West in particular should take the coarse fraction of particulate
matter into account in determining whether a source meets the threshold
for BART applicability.
---------------------------------------------------------------------------
\13\ See Fine particles: Overview of Atmospheric Chemistry,
Sources of Emissions, and Ambient Monitoring Data, Memorandum to
Docket OAR 2002-0076, April 1, 2005.
\14\ These methods are described at the following Web site:
http://vista.cira.colostate.edu/improve/Tools/ReconBext/reconBext.htm
.
\15\ Grand Canyon Visibility Transport Commission,
Recommendations for Improving Western Vistas, Report to the U.S.
EPA, June 10, 1996.
---------------------------------------------------------------------------
Because long-range transport of fine particles is of particular
concern in the formation of regional haze, we also
[[Page 39114]]
believe that it is very important to estimate the PM2.5
fraction of direct particulate emissions as correctly as possible. In
addition, we believe that air quality modeling results will be more
meaningful provide a more accurate prediction of a source's impact on
visibility if the inputs account for the relative particle size of
directly emitted particulate matter (e.g. PM10 vs.
PM2.5).
States should consider whether their current test methods for
measuring particulate matter emissions from stationary sources account
for the condensible fraction of particulate matter and consider
revising any such stationary source test methods to account for the
condensible fraction of particulate emissions. See the source testing
technical support document (TSD) in the docket for this rule, which
discusses test methods for particulate matter in more detail.\16\
---------------------------------------------------------------------------
\16\ Fine particles: Overview of Source Testing Approaches,
Memorandum to Docket OAR 2002-0076, April 1, 2005.
---------------------------------------------------------------------------
Ammonia. In regard to ammonia, we believe there is sufficient
uncertainty about emission inventories and about the potential efficacy
of control measures from location to location such that the most
appropriate approach for States to take is a case-by-case approach.
There are scientific data illustrating that ammonia in the atmosphere
can be a precursor to the formation of particles such as ammonium
sulfate and ammonium nitrate; \17\ however, it is less clear whether a
reduction in ammonia emissions in a given location would result in a
reduction in particles in the atmosphere and a concomitant improvement
in visibility. In other words, the question of whether ammonia
contribute to visibility impairment in a specific instance can be a
difficult one.
---------------------------------------------------------------------------
\17\ See Fine particles: Overview of Atmospheric Chemistry,
Sources of Emissions, and Ambient Monitoring Data, Memorandum to
Docket OAR 2002-0076, April 1, 2005.
---------------------------------------------------------------------------
It may be that States will not be faced often with the question of
addressing ammonia in making BART determinations. As noted above,
States are required to make BART determinations only for stationary
sources that fall within certain industrial categories. The types of
sources subject to the BART provisions are not typically significant
emitters of ammonia. Because of this, it is unlikely that including
ammonia on the list of visibility-impairing pollutants in the BART
guidelines would have much impact on the States' determinations of
whether a source is BART-eligible. Thus, while ammonia can contribute
to visibility impairment, we believe the decision whether to consider
ammonia as a visibility-impairing pollutant in a specific case where a
potential BART source actually emits more than 250 tons per year of
ammonia is best left to the State.
VOCs. Organic compounds can be categorized according to their
varying degrees of volatility: highly reactive, volatile compounds with
six or fewer carbon atoms which indirectly contribute to PM formation
through the formation of oxidizing compounds such as the hydroxyl
radical and ozone; semivolatile compounds with between seven and 24
carbon atoms which can exist in particle form and can readily be
oxidized to form other low volatility compounds; and high molecular
weight organic compounds--those with 25 carbon atoms or more and low
vapor pressure--which are emitted directly as primary organic particles
and exist primarily in the condensed phase at ambient temperatures. The
latter organic compounds are considered to be primary PM2.5
emissions and not VOCs for BART purposes.
Current scientific and technical information shows that
carbonaceous material is a significant fraction of total
PM2.5 mass in most areas and that certain aromatic VOC
emissions such as toluene, xylene, and trimethyl-benzene are precursors
to the formation of secondary organic aerosol.\18\ However, while
progress has been made in understanding the role of VOCs in the
formation of organic PM, this relationship remains complex, and issues
such as the relative importance of biogenic versus anthropogenic
emissions remain unresolved.
---------------------------------------------------------------------------
\18\ Ibid.
---------------------------------------------------------------------------
Therefore we believe that the best approach for States to follow in
considering whether VOC emissions are precursors to PM2.5
formation is a case-by-case approach. States should consider, in
particular, whether a source's VOC emissions are those higher-carbon
VOCs that are more likely to form secondary organic aerosols. In
addition, given the variable contribution of a given amount of VOC
emissions to PM2.5 formation, States may also wish to
exercise discretion in considering only relatively larger VOC sources
to be BART-eligible.
After careful consideration of the comments, we agree with
commenters who assert that EPA should not suggest a general distinction
between the relative contributions of urban and rural VOC emissions to
particle formation. The state of knowledge in this area is complex and
rapidly evolving. Monitoring data in the East \19\ suggest that there
may be a greater contribution to particle formation in urban areas from
VOCs as compared to rural areas, but we recognize that further research
is needed to better determine the extent of the contribution of
specific VOC compounds to organic PM mass. We do not agree, however,
with commenters who make the blanket assertion that rural VOCs are not
a significant contributor to particle formation, as it is possible that
in specific areas, such as where NOX emissions are high,
rural anthropogenic VOCs could potentially play a significant role.
---------------------------------------------------------------------------
\19\ Ibid.
---------------------------------------------------------------------------
Discussion of the Term ``Potential'' Emissions
Comments. A number of commenters were critical of the restriction
in the regional haze rule that allows States to credit federally
enforceable limitations on emissions but not limitations that are
enforceable only by States and local agencies. These commenters
believed that this restriction had been rejected by the D.C. Circuit
for a number of other EPA regulations and noted that EPA has developed
policies that currently credit state-enforceable limits. The comments
recommended that EPA issue guidance consistent with what commenters
claimed were current policies for other regulations. In addition, we
received comments arguing that in determining whether a source is a
major stationary source, the States should consider a source's actual--
rather than potential--emissions. These commenters stated that using a
source's potential emissions overstates a source's actual emissions and
impacts on visibility.
Final rule. CAA section 169A(g)(7) defines a ``major stationary
source'' as a source with the potential to emit 250 tons or more any
pollutant. Based inter alia on that statutory definition, EPA's
implementing regulations define BART-eligible sources as those with the
potential to emit 250 tons or more of any air pollutant. As these
definitions clearly require consideration of a source's potential
emissions, the guidelines state that a State should determine whether a
source's potential emissions exceed the 250 ton threshold in
determining whether the source is BART-eligible.
As explained in the 2001 and 2004 proposed guidelines, the regional
haze regulations define ``potential to emit.'' The guidelines repeat
that regulatory definition and provide an example illustrating its
application. EPA did not propose to change the definition in 2001 or
2004, but merely highlighted the
[[Page 39115]]
current definition in 40 CFR 51.301. Although we noted in the 2001
proposed guidelines that we expected to undertake a rulemaking to
determine whether only federally enforceable limitations should be
taken into account in the regional haze program definition, we have not
yet begun the process for such a rulemaking. However, we consider the
comments criticizing EPA's definition of ``potential to emit'' as a
request for reconsideration of the visibility regulations and will take
these requests into account in determining any future rulemaking
efforts to address the general definition of ``potential to emit.'' For
the time being, we believe that States may consider federally
enforceable limits or emissions limitations in State permits, which are
enforceable under State law, in determining a source's ``potential to
emit.''
Discussion of What Emissions Units Should Be Considered Part of a
``Stationary Source''
Comments. A number of comments in 2001 expressed concern with our
statement that a ``support facility'' should be grouped with a primary
facility in determining which emissions units belong to the same
industrial grouping. These comments generally coincided with comments
discussed above that EPA should determine BART on a plantwide basis,
rather than by aggregating emissions units. Commenters on the 2004
reproposal noted with approval the clarification that ``support
facilities'' should only be considered BART-eligible if these units
themselves were both constructed within the 1962-1977 time frame and
fell within one of the listed source categories.
Two commenters felt that we should more clearly define the BART-
eligible source, either by identifying emission units within source
categories, or by somehow accounting for the specific set of emission
units, within the fenceline, to which controls would logically apply.
Final rule. The guidelines continue to note that the definition of
``building, structure or facility'' in the regional haze rule is based
upon aggregating emissions units within the same industrial grouping.
This discussion in the guidelines is consistent with the language in
the definition of ``building, structure or facility'' in the regional
haze rule which contains a specific reference to the 2-digit SIC
classifications. The BART guidelines refer to this definition and
explain how 2-digit SIC codes are used in determining the scope of BART
for a given plantsite. (In the rare situation where industrial
groupings in separate 2-digit SIC codes exist at a single plant site,
then there would be more than one separate ``stationary source''
present. In that situation, each ``stationary source'' should be looked
at individually for purposes of determining BART-eligibility.)
We agree that more clarity is needed to account for situations
where a specific set of units constitute the logical set to which BART
controls would apply. The CAA requires BART at certain major stationary
sources. Accordingly we believe it could be appropriate, at the BART
determination step, for States to allow sources to ``average''
emissions across a set of BART-eligible emission units within a
fenceline, so long as the amount of emission reductions from each
pollutant being controlled for BART would be at least equal to those
reductions that would be obtained by simply controlling each unit. We
have added language to the guidelines to this effect.
Step 4: Identify the Emission Units and Pollutants That Constitute the
BART-Eligible Source
Background. The final step in identifying a ``BART-eligible
source'' is to use the information from the previous three steps to
identify the universe of equipment that makes up the BART-eligible
source. The 2001 and 2004 proposed BART guidelines stated that if the
emissions from the list of emissions units at a stationary source
exceed a potential to emit of 250 tons per year for any individual
visibility-impairing pollutant, then that collection of emissions units
is a BART-eligible source. The guidelines also stated that a BART
analysis would be required for each visibility-impairing pollutant
emitted from this collection of emissions units.
In the 2004 reproposed BART guidelines, we noted that we believed
that section 169A(b)(2)(A) of the CAA requires a State to undertake a
BART analysis for ``any'' visibility-impairing pollutant emitted by a
BART-eligible source, regardless of the amount emitted. We proposed,
however, to provide the States with the flexibility to identify de
minimis levels for pollutants at BART-eligible sources, but limited
that flexibility so that any such de minimis levels could not be higher
than those used in the PSD program: 40 tons per year for
SO2, NOX, and VOC, and 15 tons per year from
PM10. We requested comment on this provision and on the use
of de minimis values.
Discussion of Whether To Include All Emitted Visibility-Impairing
Pollutants in the BART Analysis
Comments. A number of commenters supported the concept of including
all pollutants in the BART analysis once an individual pollutant
triggers the BART review. Other commenters, although supportive of the
concept generally, recommended that we should add the pollutants
together before the comparison with the threshold.
A number of commenters disagreed with EPA's conclusion that the CAA
requires States to make a BART determination for any visibility-
impairing air pollutant emitted by a BART eligible source. These
commenters stated that undertaking a BART analysis for all pollutants
emitted by a major stationary source is an unnecessary administrative
burden with minimal environmental benefit. Commenters argued that
Congress intended for BART to apply only to those pollutants for which
a source is major. Commenters accordingly recommended that the 250 ton
per year threshold apply to each pollutant emitted by a source and that
BART apply only to those pollutants which meet this threshold. A number
of these commenters argued alternatively that only those pollutants
from a source demonstrated, individually, to cause or contribute to
visibility impairment are required to go through a BART determination.
Final rule. We disagree with the comment that emissions of
different visibility-impairing pollutants must be added together to
determine whether a source exceeds the 250 ton per year threshold. The
CAA, in section 169A(g)(7), defines a ``major stationary source'' as
one with the potential to emit 250 tons or more of ``any pollutant.''
We disagree with comments that the BART analysis is required only
for those pollutants that individually exceed the 250 ton per year
threshold. Section 169A(b)(2)(A) specifically requires States to submit
SIPs that include a requirement that a major stationary source
which, as determined by the State * * * emits any air pollutant
which may reasonably be anticipated to cause or contribute to any
impairment of visibility in any [Class I area], shall procure,
install, and operate * * * the best available retrofit technology,
as determined by the State * * * for controlling emissions from such
source for the purpose of eliminating or reducing any such
impairment.
The regional haze regulations similarly require that the States submit
a SIP that contains
[[Page 39116]]
A determination of BART for each BART-eligible source in the State
that emits any air pollutant which may reasonably be anticipated to
cause or contribute to any impairment of visibility in any mandatory
Class I Federal area.
40 CFR 51.308(e)(1)(ii). Nothing in these statutory or regulatory
requirement suggests that the BART analysis is limited to those
pollutants for which a source is considered major. At best, these
provisions can be read as requiring a BART determination only for those
emissions from a specific source which do, in fact, cause or contribute
to visibility impairment in a particular Class I area, or which could
reasonably be anticipated to do so. Commenters, however, have not
presented any evidence that as a general matter emissions of less than
250 tons per year of PM2.5, SO2, or other
visibility-impairing pollutants from potential BART sources do not
``cause or contribute to any impairment of visibility'' in any of the
Class I areas covered by the regional haze rule. As there is no such
evidence currently before us, there is no basis to conclude that the
States are required to make BART determinations only for those
pollutants emitted in excess of 250 tons per year.
At the same time, we agree with certain commenters that the CAA
does not require a BART determination for any visibility impairing
pollutant emitted by a source, regardless of the amount. After
reviewing the language of the Act and the comments received, we have
concluded that our interpretation of the relevant language in section
169A(b)(2)(A) of the Act in the 2004 proposed guidelines is not
necessarily the best reading of the BART provisions. Section
169A(b)(2)(A) of the Act can be read to require the States to make a
determination as to the appropriate level of BART controls, if any, for
emissions of any visibility impairing pollutant from a source. Given
the overall context of this provision, however, and that the purpose of
the BART provision is to eliminate or reduce visibility impairment, it
is reasonable to read the statute as requiring a BART determination
only for those emissions from a source which are first determined to
contribute to visibility impairment in a Class I area.
The interpretation of the requirements of the regional haze program
reflected in the discussion above does not necessitate costly and time-
consuming analyses. Consistent with the CAA and the implementing
regulations, States can adopt a more streamlined approach to making
BART determinations where appropriate. Although BART determinations are
based on the totality of circumstances in a given situation, such as
the distance of the source from a Class I area, the type and amount of
pollutant at issue, and the availability and cost of controls, it is
clear that in some situations, one or more factors will clearly suggest
an outcome. Thus, for example, a State need not undertake an exhaustive
analysis of a source's impact on visibility resulting from relatively
minor emissions of a pollutant where it is clear that controls would be
costly and any improvements in visibility resulting from reductions in
emissions of that pollutant would be negligible. In a scenario, for
example, where a source emits thousands of tons of SO2 but
less than one hundred tons of NOX, the State could easily
conclude that requiring expensive controls to reduce NOX
would not be appropriate. In another situation, however, inexpensive
NOX controls might be available and a State might reasonably
conclude that NOX controls were justified as a means to
improve visibility despite the fact that the source emits less than one
hundred tons of the pollutant. Moreover, as discussed below, we are
revising the regional haze regulations to allow the States to exempt de
minimis emissions of SO2, NOX, and
PM2.5 from the BART determination process which should help
to address the concerns of certain commenters associated with the
burden of a broad BART analysis.
De minimis levels
Comments. Many commenters agreed that we should establish de
minimis levels for individual pollutants in order to allow States and
sources to avoid BART determinations for pollutants emitted in
relatively trivial amounts. Many commenters suggested that States would
be unlikely to impose emission limits for pollutants emitted at the
proposed de minimis levels because it would not be cost-effective to do
so and such emission reductions could not be expected to produce any
perceptible improvements in visibility. Several commenters agreed that
the pollutant coverage requirements for BART eligibility should be
consistent with those for the PSD program, but others argued that BART
should be required only for pollutants emitted in amounts greater than
250 tons per year. Commenters also noted that the guidelines were not
clear as to whether the de minimis provision would apply on a plant-
wide or unit by unit basis. A few commenters also noted that the final
guidelines should clarify where in the BART determination process de
minimis levels may be used.
Other commenters opposed the use of de minimis exemptions. These
commenters argued that it would be unreasonable to rule categorically
that a certain level of emissions had a trivial impact on visibility
without assessing the impacts of these emissions in particular
circumstances. These commenters argued that States should consider the
emissions of all visibility-impairing pollutants in a BART
determination regardless and that, consequently, there should be no de
minimis levels.
Final rule. As proposed in 2004, we believe that it is reasonable
to give States the flexibility to establish de minimis levels so as to
allow them to exempt from the BART determination process pollutants
emitted at very low levels from BART-eligible sources. As explained by
the D.C. Circuit, ``categorical exemptions from the requirements of a
statute may be permissible `as an exercise of agency power, inherent in
most statutory schemes, to overlook circumstances that in context may
fairly be considered de minimis.' '' \20\ The ability to create de
minimis exemptions from a statute is a tool to be used in implementing
the legislative design.\21\
---------------------------------------------------------------------------
\20\ EDF et al. v. EPA, 82 F.3d 451, 466 (D.C. Cir. 1996) citing
Alabama Power v. Costle, 636 F.2d 323 (D.C. Cir. 1979).
\21\ Id.
---------------------------------------------------------------------------
The intent of Congress in requiring controls on emissions from
certain major stationary sources was to eliminate or reduce any
anticipated contribution to visibility impairment from these sources.
This, as section 169A(b)(2)(A) states, is the ``purpose'' of BART. In
making a determination as to the appropriate level of controls,
however, the States are required to take into account not only the
visibility benefits resulting from imposing controls on these sources
but also the costs of complying with the BART provision. The BART
provision is accordingly designed to ensure that the States take into
consideration all emissions of certain stationary sources in making a
BART determination, but also to provide States with the flexibility to
include the costs and benefits of controlling these sources in the
calculus of determining the appropriate level of BART.
We believe it would be permissible for States to create de minimis
levels at a low level. If a State were to undertake a BART analysis for
emissions of less than 40 tons of SO2 or NOX or
15 tons of PM10 from a source, it is unlikely to result in
anything but a trivial improvement in visibility. This is
[[Page 39117]]
because reducing emissions at these levels would have little effect on
regional emissions loadings or visibility impairment. We believe most
States would be unlikely to find that the costs of controlling a few
tons of emissions were justified. Because the overall benefits to
visibility of requiring BART determinations for emissions of less than
the de minimis levels would be trivial, we are amending the regional
haze rule to make clear that the States have this flexibility.
The de minimis levels discussed today apply on a plant-wide basis.
Applying de minimis levels on a unit by unit basis as suggested by
certain commenters could exempt hundreds of tons of emissions of a
visibility-impairing pollutant from BART analysis. In at least some of
the twenty-six source categories covered by the BART provisions, a
single control device can be used to control emissions from multiple
units. Thus, it is possible that while emissions from each unit are
relatively trivial, the costs of controlling emissions from multiple
units might be cost-effective in light of the BART-eligible source's
total emissions of the pollutant at issue. States should consider the
control options in such situations and determine the appropriate
approach for the specific source.
We are revising the regional haze rule to provide States with the
ability to establish de minimis levels up to the levels proposed in
2004. We believe States may, if they choose, exclude from the BART
determination process potential emissions from a source of less than
forty tons per year of SO2 or NOX, or 15 tons per
year for PM10. (Note also that for sources that are BART-
eligible for one pollutant, we also believe that States could allow
those sources to model the visibility impacts of pollutants at levels
between de minimis and 250 tons in order to show that the impact is
negligible and should be disregarded. See section D below). In the
guidelines, we include this as part of the BART determination in
section IV of the guidelines. (We note that these emission levels
represent the maximum allowable de minimis thresholds--States retain
their discretion to set the thresholds at lesser amounts of each
pollutant, or to not provide any pre-determined de mininis levels.) We
believe that this approach is the clearest method for exempting trivial
emissions from the BART determination process. Alternatively, States
may find it useful to exclude de minimis emissions in identifying
whether a source is subject to BART in section III of the guidelines.
Either approach is consistent with the regulation issued in this rule.
D. How To Determine Which BART-eligible Sources Are ``Subject to BART''
Cause or Contribute
Background. Under section 169A(b)(2)(A) of the Act, each State must
review its BART eligible sources and determine whether they emit ``any
air pollutant which may reasonably be anticipated to cause or
contribute to any impairment of visibility in [a Class I] area.'' If a
source meets this threshold, the State must then determine what is BART
for that source.
Proposed rule. In the reproposed guidelines, we identified three
options for States to use in determining which BART-eligible sources
meet the test set forth in section 169A(b)(2)(A) of the CAA. To
determine whether a BART-eligible source is ``reasonably anticipated to
cause or contribute to visibility impairment,'' the first proposed
option was that a State could choose to consider the collective
contribution of emissions from all BART-eligible sources and conclude
that all BART-eligible sources within the State are ``reasonably
anticipated to cause or contribute'' to some degree of visibility
impairment in a Class I area. The preamble to the 1999 regional haze
rule explains at length why we believe that looking to the collective
contribution of many sources over a broad area is a reasonable
approach, and we explained in the 2004 reproposed guideline that we
believed that a State's decision to use a cumulative analysis at this
stage of the BART determination process would be consistent with the
CAA and the findings of the D.C. Circuit in American Corn Growers.
The second proposed option was to allow a State to demonstrate,
using a cumulative approach, that none of its BART-eligible sources
contribute to visibility impairment. Specifically, we proposed to
provide States with the option of performing an analysis to show that
the full group of BART-eligible sources in a State cumulatively do not
cause or contribute to visibility impairment in any Class I areas.
As a third option, we proposed that a State may choose to determine
which sources are subject to BART based on an analysis of each BART-
eligible source's individual contribution. We labeled this option as an
``Individualized Source Exemption Process,'' and proposed that States
use an air quality model to determine an individual source's
contribution to visibility impairment, calculated on a 24 hour basis,
using allowable emissions, and compared to an established threshold.
Comments. Several commenters expressed the view that EPA was
misinterpreting the American Corn Growers case to allow the States to
apply a collective contribution test in determining whether BART-
eligible sources are subject to BART. These commenters took the
position that, because this approach does not allow for a source to
show that it does not individually cause or contribute to visibility
impairment, it is incompatible with the language of section
169A(b)(2)(A)of the Act. They argued that EPA should modify the
provisions in the proposed rule to ensure that an individual source is
afforded the opportunity to conduct an analysis to demonstrate that its
emissions do not impair visibility in any Class I area. Conversely,
several commenters indicated that the option to determine that all
potential BART sources contribute to regional haze should be the
starting point of determining BART eligibility.
Many industry commenters and some States supported the second
proposed option which would allow a State to demonstrate through an
analysis of the collective contribution of all its BART-eligible
sources that none of these sources contribute to visibility impairment.
Several of these commenters added, however, that if this cumulative
analysis were to show a contribution, then, consistent with the
decision in American Corn Growers, the State must allow each individual
source to demonstrate that its own emissions do not, by themselves,
contribute to the problem of visibility impairment. One commenter
requested clarification on what visibility threshold a State should use
in determining that no sources are reasonably anticipated to cause or
contribute to any impairment in a Class I area.
A number of commenters supported the third option for determining
BART applicability based on an analysis of source-specific effects on
visibility. However, many of the commenters stated that the CAA
requires that the States either conduct such an analysis in determining
those sources subject to BART, or allow an individual source to make a
showing that it does not cause or contribute to visibility impairment.
In addition, although supportive of the general notion of allowing for
an exemption process for BART-eligible sources, several commenters
stated that the third option contained burdensome modeling
requirements, and that States need a more flexible, straightforward,
[[Page 39118]]
and less costly method to make the ``cause or contribute''
determination.
Several environmental groups commented that the proposed options
potentially go too far in allowing sources to be exempted from the BART
requirements. These commenters asserted that EPA should clarify that
States may not allow a BART-eligible source to avoid the BART
requirements without an affirmative demonstration by the State, or by
the source, showing that the source does not emit any air pollutant
which may reasonably be anticipated to cause or contribute to any
impairment of visibility in a Class I area. Absent such a
demonstration, they argue, a State may not choose to waive the
requirement to conduct a BART review of the source.
Final rule. The final BART guidelines adopt the general approach
contained in the reproposal, providing the States with several options
for identifying the sources subject to BART. The final BART guidelines
describe the options contained in the reproposal as well as one new
option. The discussion of options in the final guidelines are
structured somewhat differently from the reproposal, and the options
are explained in greater detail. The guidelines reaffirm that a State
may choose to consider all BART-eligible sources to be subject to BART,
and to make BART determinations for all its BART-eligible sources.\22\
For States that choose to consider exempting some or all of their BART-
eligible sources from review, the guidelines then discuss three options
that States may use to determine whether its sources are ``reasonably
anticipated to cause or contribute'' to visibility impairment at a
Class I area. Options 1 and 3 are similar to options in the 2004
reproposal; under option 1, States may use an individual source
attribution approach, while option 3 provides the States with an
approach for demonstrating that no sources in a State should be subject
to BART. Option 2 is new; it is an approach for using model plants to
exempt individual sources with common characteristics.
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\22\ States choosing this approach should use the data being
developed by the regional planning organizations, or on their own,
as part of the regional haze SIP development process to make the
showing that the State contributes to visibility impairment in one
or more Class I areas.
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Threshold for visibility impact. One of the first steps in
determining whether sources cause or contribute to visibility
impairment for purposes of BART is to establish a threshold (quantified
in units called ``deciviews'') against which to measure the visibility
impact of one or more sources. We believe that a single source that is
responsible for a 1.0 deciview change or more should be considered to
``cause'' visibility impairment; a source that causes less than a 1.0
deciview change may still contribute to visibility impairment and thus
be subject to BART.
The guidelines note that because of varying circumstances affecting
different Class I areas, the appropriate threshold for determining
whether a source ``contributes to any visibility impairment'' for the
purposes of BART may reasonably differ across States. Although the
appropriate threshold may vary, the Guidelines state that the
contribution threshold used for BART applicability should not be higher
than 0.5 deciviews. We discuss threshold issues in greater detail in
the subsection immediately following this one, entitled Metric for
Visibility Degradation.
Pollutants
The guidelines direct that States should look at SO2,
NOX, and direct particulate matter (PM) emissions in
determining whether sources cause or contribute to visibility
impairment, including both PM10 and PM2.5.
Consistent with the approach for identifying BART-eligible sources,
States do not need to consider less than de minimis emissions of these
pollutants from a source.
States may use their best judgement to determine whether VOC or
ammonia emissions are likely to have an impact on visibility in an
area. In addition, they may use PM10 or PM2.5 as
an indicator for PM2.5 in determining whether a source is
subject to BART. In determining whether a source contributes to
visibility impairment, however, States should distinguish between the
fine and coarse particle components of direct particulate emissions.
Although both fine and coarse particulate matter contribute to
visibility impairment, the long-range transport of fine particles is of
particular concern in the formation of regional haze. Air quality
modeling results used in the BART determination will provide a more
accurate prediction of a source's impact on visibility if the inputs
into the model account for the relative particle size of any directly
emitted particulate matter (i.e. PM10 vs. PM2.5).
We believe that PM10 is likely to contribute more to
regional haze in arid areas than humid areas. As the Grand Canyon
Visibility Transport Commission (GCTVC) recognized,\23\ States in the
arid West, in particular, will need to take the coarse fraction of
particulate matter into account in determining whether a source meets
the threshold for BART applicability.
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\23\ Grand Canyon Visibility Transport Commission,
Recommendations for Improving Western Vistas, Report to the U.S.
EPA, June 10, 1996.
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Option 1. We agree with commenters supporting the use of an
individual source analysis in determining if a BART-eligible source
causes or contributes to visibility impairment. Consistent with
American Corn Growers, this option provides a method for a State to
evaluate the visibility impact from an individual source and show that
the source is not reasonably anticipated to cause or contribute to
visibility degradation in a Class I area and thus may be exempt from
BART. (Note also that an individual source analysis is used to inform
the BART determination). In general, a dispersion model is used to
assess the visibility impact from a single source, and that impact is
compared to a threshold which is determined by the State. The threshold
(quantified in deciviews) is the numerical metric that is used to
define ``cause or contribute''; if a source's impact is below the
threshold, a State may exempt the source from BART; otherwise the
source would be subject to BART.
We discuss specific issues on the individualized source attribution
process, including changes since proposal and issues raised by
commenters, in the subsections immediately following this one: Metric
for visibility degradation; Use of CALPUFF for visibility modeling; The
use of natural conditions in determining visibility impacts for
reasonable progress and comparison to threshold values; Modeling
protocol; and Alternatives for determining visibility impacts from
individual sources.
Option 2. In the final guideline, we describe a modified approach,
using model plants based on representative sources sharing certain
characteristics, that the States may use to simplify the BART
determination process, either to exempt (individually or as a group)
those small sources that are not reasonably anticipated to cause or
contribute to visibility impairment, or to identify those large sources
that clearly should be subject to BART review. States could use the
CALPUFF model, for example, to estimate levels of visibility impairment
associated with different combinations of emissions and distances to
the nearest Class I area. In carrying out this approach, the State
could then reflect groupings of specific types of sources with
important common characteristics, such as emissions, stack heights and
plume characteristics, and develop ``composite model plants.'' Based on
CALPUFF
[[Page 39119]]
analyses of these model plants, a State may find that certain types of
sources are clearly reasonably anticipated to cause or contribute to
visibility impairment. Conversely, representative plant analyses may
show that certain types of sources are not reasonably anticipated to
cause or contribute to visibility impairment. Based on the modeling
results, a State could exempt from BART all sources that emit less than
a certain amount per year and that are located a certain distance from
the nearest Class I area.
Our analyses of visibility impacts from model plants provide a
useful example of the type of analyses that might be used to exempt
categories of sources from BART.\24\ Based on our model plant analysis,
EPA believes that a State could reasonably choose to exempt sources
that emit less than 500 tons per year of NOX or
SO2 (or combined NOX and SO2), as long
as they are located more than 50 kilometers from any Class I area; and
sources that emit less than 1000 tons per year of NOX or
SO2 (or combined NOX and SO2) that are
located more than 100 kilometers from any Class I area.
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\24\ Supplement to CALPUFF Analysis in Support of the June 2005
Changes to the Regional Haze Rule, U.S. Environmental Protection
Agency, June 15, 2005, Docket No. OAR-2002-0076.
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In our analysis, we developed two model plants (a EGU and a non-
EGU), with representative plume and stack characteristics, for use in
considering the visibility impact from emission sources of different
sizes and compositions at distances of 50, 100 and 200 kilometers from
two hypothetical Class I areas (one in the East and one in the West).
Because the plume and stack characteristics of these model plants were
developed considering the broad range of sources within the EGU and
non-EGU categories, they do not necessarily represent any specific
plant. However, the results of these analyses may be instructive in the
development of an exemption process for groups of BART-eligible
sources, without modeling each of these sources individually.
States may want to conduct their own model plant analysis that take
into account local, regional, and other relevant factors (such as
meteorology, sulfur dioxide, nitrogen dioxide, and ammonia). If so, you
may want to consult your EPA Regional Office to ensure that any
relevant technical issues are resolved before you conduct your
modeling.
In preparing our hypothetical examples, we have made a number of
assumptions and exercised certain modeling choices; some of these have
a tendency to lend conservatism to the results, overstating the likely
impacts, while others may understate the modeling results. On balance,
when all of these factors are considered, we believe that our examples
reflect realistic treatments of the situations being modeled.\25\ A
summary of the more significant elements and their implications is
provided below.
\25\ CALPUFF Analysis in Support of the June 2005 Changes to the
Regional Haze Rule, U.S. Environmental Protection Agency, June 15,
2005, Docket No. OAR-2002-0076.
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Features of the modeling examples which may understate visibility
impacts
An annual emission rate was used for the example modeling
(e.g. 10,000 TPY divided by 365 days divided by 24 hours). ``Real
world'' sources have variable emission rates, and in any 24 hour period
may be operating well above the annual rate.
The monthly average relative humidity was used, rather
than the daily average humidity, and would contribute to lowering the
peak values in daily model averages.
A 24-hour average was calculated from modeled hourly
visibility impacts, reducing the impact of any one particular hour that
could be higher due to a number of meteorological effects.
Features of the modeling examples which may overstate visibility
impacts
We located receptors using a grid of concentric circles
for distances of 50, 100 and 200 km. A receptor was placed every 10
degrees around each circle, and highest impacts were reported
regardless of direction from the source. In actuality, receptors would
be located only in the Class I area, or in only one direction from the
source.
We used simplified chemistry (i.e. for conversion of
SO2 and NOX to fine particles) and disperson
techniques which tend to overstate model impacts.
Special care should be used to ensure that the criteria used in the
modeling are appropriate for a given State. Our modeling may not be
appropriate for every region of the country, due to the unique
characteristics of different Class I areas and varying meteorological
and geographical conditions in different regions. In addition, States
may want to design their own model plants taking into account the types
of sources at issue in their region.
Option 3. Under the BART guidelines, a State may consider exempting
all its BART-eligible sources from BART by conducting analyses that
show that all of the emissions from BART-eligible sources in their
State, taken together, are not reasonably anticipated to cause or
contribute visibility impairment. To make such a showing, a State could
use CALPUFF or another appropriate dispersion model to evaluate the
impacts of individual sources on downwind Class I areas, aggregating
those impacts to determine the collective contribution from all-BART
eligible sources in the State. A State with a sufficiently large number
of BART-eligible sources could also make such a showing using a
photochemical grid model.\26\
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\26\ For regional haze applications, regional scale modeling
typically involves use of a photochemical grid model that is capable
of simulating aerosol chemistry, transport, and deposition of
airborne pollutants, including particulate matter and ozone.
Regional scale air quality models are generally applied for
geographic scales ranging from a multi-state to the continental
scale. Because of the design and intended applications of grid
models, they may not be appropriate for BART assessments, so States
should consult with the appropriate EPA Regional Office prior to
carrying out any such modeling.
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We agree with commenters who pointed out that the option of
allowing a State to demonstrate that the full group of BART-eligible
sources in the State do not contribute to visibility impairment would,
by default, satisfy an individual source contribution assessment.
Commenters have not shown any reason to believe that if the sum total
of emissions from the BART-eligible sources in a State do not ``cause
or contribute'' to visibility impairment in any Class I area, that
emissions from one such source will meet the threshold for BART
applicability. A State following this approach accordingly need not
undertake an affirmative demonstration based on a source by source
analysis of visibility impacts to find that its sources are not subject
to BART.
Metric for Visibility Degradation
Background. The 2004 reproposed guidelines contained a proposed
threshold for the States to use in determining whether an individual
source could be considered to cause visibility impairment in a Class I
area. We proposed a 0.5 deciview change relative to natural background
conditions,\27\ as a numerical threshold for making this
determination.\28\
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\27\ Guidance for Estimating Natural Visibility Conditions Under
the Regional Haze Rule, ( U.S. Environmental Protection Agency,
September 2003. http://www.epa.gov/ttncaaa1/t1/memoranda/rh_envcurhr_gd.pdf.
Natural background conditions, expressed in
deciviews, are defined for each Class I area. EPA has issued
guidance for estimating natural background conditions which has
estimates of default conditions as well as measures to develop
refined estimates of natural conditions.
\28\ In the proposal we noted that a 0.5 deciview change in
visibility is linked to ``perceptibility,'' or a just noticeable
change in most landscapes. National Acid Precipitation Assessment
Program (NAPAP), Acid Deposition: State of Science and Technology
Report 24, Visibility: Existing and Historical Conditions--Causes
and Effects (Washington, DC, 1991) Appendix D at 24-D2 (``changes in
light extinction of 5 percent will evoke a just noticeable change in
most landscapes''). Converting a 5 percent change in light
extinction to a change in deciviews yields a change of approximately
0.5 deciviews.
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[[Page 39120]]
We proposed the CALPUFF model as the preferred approach for
predicting whether a single source caused visibility impairment if the
modeled results showed impacts from the source that exceeded the
threshold on any given day during a five-year period. We also proposed
that if a source had an estimated impact on visibility of less than 0.5
deciviews, a State could choose to exempt the source from further BART
analysis.
Comments. We received numerous comments supporting the proposed
threshold. A number of commenters stated that the 0.5 deciview
threshold is appropriate given the low triggering threshold for
applicability established by Congr