Approval and Promulgation of Implementation Plans: Alabama: Final Disapproval of Revisions to the Visible Emissions Rule, 18870-18893 [2011-8032]

Agencies

• ENVIRONMENTAL PROTECTION AGENCY

[Federal Register Volume 76, Number 66 (Wednesday, April 6, 2011)]
[Rules and Regulations]
[Pages 18870-18893]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-8032]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R04-OAR-2005-AL-0002-201047; FRL-9290-3]


Approval and Promulgation of Implementation Plans: Alabama: Final 
Disapproval of Revisions to the Visible Emissions Rule

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: EPA is taking final action to amend an October 15, 2008, final 
rulemaking on two State Implementation Plan (SIP) revisions regarding 
the State of Alabama's rules for visible emissions from certain 
stationary sources. EPA has now determined upon reconsideration that 
Alabama's SIP revisions, dated September 11, 2003, and August 22, 2008, 
are not approvable pursuant to the Clean Air Act (CAA or Act) section 
110(l). Accordingly, EPA is disapproving the two SIP revisions provided 
to EPA by the State of Alabama, through the Alabama Department of 
Environmental Management (ADEM), dated September 11, 2003, and August 
22, 2008 (Submittals). No further action is required by Alabama because 
the SIP revisions were not required by the CAA. As a result of this 
action, Alabama's visible emissions rule that was in the SIP prior to 
the October 15, 2008, final action will be the current SIP-approved 
rule as of the effective date of this action. EPA urges Alabama to 
undertake rulemaking that will bring its State-effective rule into 
conformance with its SIP-approved rule.

DATES: Effective Date: This rule will be effective May 6, 2011.

ADDRESSES: EPA has established a docket for this action under Docket 
Identification No. EPA-R04-OAR-2005-AL-0002. All documents in the 
docket are listed on the https://www.regulations.gov index. Although 
listed in the index, some information is not publicly available, i.e., 
Confidential Business Information (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 through https://www.regulations.gov or in hard copy at the Regulatory Development 
Section, Air Planning Branch, Air, Pesticides and Toxics Management 
Division, U.S. Environmental Protection Agency, Region 4, 61 Forsyth 
Street, SW., Atlanta, Georgia 30303-8960. EPA requests that, if at all 
possible, you contact the person listed in the FOR FURTHER INFORMATION 
CONTACT section to schedule your inspection. The Regional Office's 
official hours of business are Monday through Friday, 8:30 to 4:30, 
excluding federal holidays.

FOR FURTHER INFORMATION CONTACT: Ms. Lynorae Benjamin, Chief, 
Regulatory Development Section, Air Planning Branch, Air, Pesticides 
and Toxics Management Division, Region 4, U.S. Environmental Protection 
Agency, 61 Forsyth Street, SW., Atlanta, Georgia 30303-8960. The 
telephone number is (404) 562-9040. Ms. Benjamin can also be reached 
via electronic mail at benjamin.lynorae@epa.gov.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. What is the background for this action?
II. What action is EPA taking and what is EPA's rationale for 
disapproving the submittals?
III. Response to Comments
IV. Final Action
V. Statutory and Executive Order Reviews

I. What is the background for this action?

    This action follows three key EPA actions regarding Alabama's 
request for approval of the two visible emissions SIP revisions. The 
first was an October 15, 2008, final rule (73 FR 60957) approving 
revisions to the Alabama SIP embodied in two submittals dated September 
11, 2003, and August 22, 2008 (Submittals). The second was an April 3, 
2009, action granting a February 25, 2009, petition for reconsideration 
on the October 15, 2008, final action which had approved the SIP 
revisions. The third was an October 2, 2009, proposed rule (74 FR 
50930) identifying two alternative options being considered by EPA as 
part of the reconsideration process (the alternative proposals were 
either to affirm the October 15, 2008, rulemaking, thereby approving 
Alabama's Submittals or to amend the October 15, 2008, rulemaking, 
thereby disapproving Alabama's Submittals). EPA has now determined that 
Alabama's Submittals are not approvable pursuant to CAA section 110(l). 
Detailed background information for this action is available in the 
proposed rulemaking published on October 2, 2009. 74 FR 50930.
    In relevant but brief part, on September 11, 2003, ADEM submitted a 
voluntary \1\ request for EPA approval of a SIP revision (2003 
Submittal) containing proposed revisions to the existing EPA-approved 
visible emissions portion of the Alabama SIP, found at Alabama 
Administrative Code (AAC) 335-3-4-.01, ``Visible Emissions,'' and 
pertaining to sources of particulate matter (PM) emissions.\2\ In

[[Page 18871]]

an action published on April 12, 2007 (72 FR 18428), EPA proposed to 
approve the 2003 Submittal contingent upon the State of Alabama 
submitting a revised SIP submittal addressing EPA's concerns regarding 
impacts of the rule changes on attainment of the National Ambient Air 
Quality Standards (NAAQS), as set forth in 72 FR 18428-18434. EPA's 
proposal notice explained that the State would have to provide EPA with 
a revised SIP submittal consistent with certain changes described by 
EPA in the April 12, 2007, notice of proposed rulemaking before EPA 
could approve the revisions. The proposal notice also described EPA's 
rationale for requesting the additional submittal. Specifically, EPA 
noted that the 2003 Submittal was not approvable because the revision 
``would allow a source to emit at a higher allowable average opacity 
percent level (as measured by a COMS--Continuous Opacity Monitoring 
System--in six-minute increments) on a quarterly basis as well as 
allowing higher short term excursions than the current approved SIP 
allows.'' 72 FR at 18430/3. EPA further explained that ``in the absence 
of a supporting demonstration of compliance with the CAA requirements 
from the State, we believe that the 2003 SIP submittal is not 
approvable as submitted.'' Id.
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    \1\ The request was ``voluntary'' because it was not 
specifically required by the CAA or its implementing regulations, 
rather, ADEM chose to revise its rules and submit the SIP revision.
    \2\ PM particles with an aerodynamic diameter less than or equal 
to a nominal 10 micrometers are referred to as PM10; PM 
particles with an aerodynamic diameter less than or equal to a 
nominal 2.5 micrometers are referred to as PM2.5. As a 
general matter, the term ``PM'' refers to particulate matter of 
unspecified size range and includes both PM10 and 
PM2.5.
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    On August 22, 2008, Alabama, through ADEM, provided EPA with an 
amended submittal (2008 Submittal). After further evaluation, EPA 
determined that it could approve the Submittals (i.e., the 2003 
Submittal as amended by the 2008 Submittal). On October 15, 2008, EPA 
took final action to incorporate into the Alabama SIP, the revisions to 
Alabama's visible emissions rule included in the Submittals. 73 FR 
60957. EPA's rationale for its approval is discussed in that final 
action. In order to approve the Submittals in 2008, EPA relied on two 
main findings: ``(1) The revision would not increase the allowable 
average opacity levels; and (2) the relationship between changes in 
opacity and increases or decreases in ambient PM2.5 levels 
cannot be quantified readily for the sources subject to this SIP 
revision, and is particularly uncertain for short-term analyses.'' 73 
FR 60959/2. The October 15, 2008, final action was effective on 
November 14, 2008 (by its terms, the Alabama rule change became 
effective, and thus applicable to sources, on May 14, 2009).
    Following the October 2008 final action, EPA received two petitions 
for reconsideration submitted on behalf of the Alabama Environmental 
Council (AEC) and other parties (Petitioners), one on December 12, 
2008, and one on February 25, 2009. EPA considered these petitions 
under section 553(e) of the Administrative Procedures Act (APA) and the 
CAA. The first petition for reconsideration raised procedural and 
substantive concerns with EPA's October 15, 2008, final action.\3\ EPA 
denied the December 12, 2008, petition via letter on January 15, 2009. 
The second petition incorporated by reference the issues raised in the 
first petition and also identified additional substantive and 
procedural concerns not included in the first petition.\4\ EPA granted 
the Petitioners' second request for reconsideration of the October 15, 
2008, final action via letter on April 3, 2009. In that letter, EPA 
explained that it anticipated initiating a new rulemaking process to 
provide additional opportunities for public comment.
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    \3\ The Petitioners raised eight main issues: (1) EPA was 
arbitrary and capricious in failing to reopen the public comment 
period when ADEM made changes to the rule after the close of the 
public comment period; (2) EPA was arbitrary and capricious in 
deviating from rulemaking policy regarding documentation of post-
comment period meetings between EPA and ADEM and failing to meet 
with Petitioners in addition to ADEM; (3) EPA was arbitrary and 
capricious in proposing to approve a SIP revision before the rule 
had even been developed at the State level; (4) EPA failed to comply 
with rulemaking procedures by failing to complete the docket prior 
to finalizing the rulemaking package; (5) the rule should not have 
been approved because it does not represent reasonably available 
control technology requirements for SIPs because Alabama has 
nonattainment areas for PM2.5; (6) EPA's approval of the 
rule is not consistent with either Section 110(l) or 193 of the CAA 
due to likely increases in short-term particulate matter emissions; 
(7) EPA's final action is not consistent with EPA policies on excess 
emissions and director's discretion; and (8) the final rule does not 
comply with 40 CFR Part 51 because it is not an ``appropriate'' 
visible emission limitation.
    \4\ The Petitioners specifically highlighted two new issues: (1) 
The DC Circuit's decision in Sierra Club v. EPA, 551 F.3d 1019 (D.C. 
Cir. 2008) (SSM MACT decision) made the Agency's action on the SIP 
revision untenable; and (2) new documents added to the docket show 
that throughout the consideration of this matter, EPA acted in an 
arbitrary and duplicitous manner in failing to re-notice the 
rulemaking for public comment given the differences between what EPA 
required of Alabama in the April 12, 2007, proposal and what Alabama 
actually submitted for approval in its August 22, 2008, submittal.
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    On December 12, 2008, Petitioners filed a lawsuit in the Eleventh 
Circuit Court of Appeals challenging EPA's October 15, 2008, final 
action. EPA and the appellants subsequently jointly stayed the 
litigation pending the conclusion of EPA's reconsideration process. 
EPA's October 2, 2009, proposed rule was EPA's initiation of a new 
rulemaking process to reconsider its prior action on the Submittals. In 
that proposal, EPA articulated two alternative options and sought 
public comment on both. One option was to affirm the October 15, 2008, 
final action (thus approving the Submittals) and the other was to amend 
the October 15, 2008, final action (thus disapproving the Submittals). 
The bases for each alternative were described in detail in the October 
2, 2009, proposed rulemaking. 74 FR at 50932-50934. The responses to 
the comments EPA received on the October 2, 2009, proposed action are 
summarized in section III of this rulemaking.

II. What action is EPA taking and what is EPA's rationale for 
disapproving the submittals?

    EPA is now taking final action to amend its October 15, 2008, final 
action and to disapprove Alabama's 2003 and 2008 SIP Submittals 
regarding its visible emissions rule. As EPA explained in its October 
2, 2009, proposed rulemaking, the primary issue for resolution is 
whether approval of the Submittals is consistent with the requirements 
of the CAA, specifically, the requirements of section 110(l). If the 
approval were appropriate under section 110(l), EPA would need to 
consider whether it would also meet the requirements of section 193, 
given that the visible emissions rules in question were in effect prior 
to November 15, 1990, and apply to some sources that are located in 
areas designated nonattainment for one or more NAAQS. In light of the 
fact that this SIP revision would apply statewide, including 
nonattainment areas, EPA has concluded that it cannot approve the SIP 
revision under section 110(l) if it would worsen air quality by 
allowing increased emissions of criteria pollutants or precursors to 
such criteria pollutants. In particular, if the revision would result 
in increases in emissions of pollutants for which an area is designated 
nonattainment, specifically PM2.5, EPA considers that 
allowing increased emissions of such pollutants would interfere with 
the area's ability to attain the NAAQS.\5\ See, e.g., 70 FR 53

[[Page 18872]]

(January 3, 2005); 70 FR 28429 (May 18, 2005) (previous rulemaking 
actions addressing section 110(l)).
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    \5\ With respect to attainment areas, section 110(l) requires 
that an approvable SIP revision not interfere with maintenance of 
the NAAQS or any other requirement of the CAA. In some 
circumstances, allowing increases in criteria pollutants may not 
interfere with maintenance of the NAAQS. EPA has not analyzed 
whether this SIP revision would be approvable with respect to 
attainment areas only because the Submittals included rules that 
applied throughout Alabama, which includes both attainment and 
nonattainment areas, and the State did not make a showing that 
emissions from such sources would not interfere with maintenance of 
the NAAQS in attainment areas and with attainment of the NAAQS in 
nearby nonattainment areas. Similarly, EPA is not basing this 
decision on section 193 because the Submittals are not approvable 
under section 110(l); however, section 193 would have to be 
addressed before EPA could consider approval of the revisions.
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    In this particular circumstance, the analysis of whether the 
Submittals satisfy the CAA is made more difficult by the uncertainty in 
the precise relationship between the opacity of a stack emission stream 
and the mass of PM in the same emission stream at the affected sources. 
After consideration of all the issues raised by the Petitioners in 
their February 2009 petition for reconsideration, as well as comments 
received on the October 2, 2009, proposed rulemaking from many industry 
groups, individual companies, state agencies, and other non-
governmental organizations, EPA has concluded that disapproving the 
2003 and 2008 Submittals results in the interpretation of the CAA that 
is most consistent with the plain text and legislative history of the 
CAA, as well as the air quality goals set forth in the CAA. What 
follows is EPA's explanation of its analysis, which involves a 
discussion of the following: (1) The role of visible emissions in NAAQS 
attainment and maintenance; (2) the history of Alabama's visible 
emissions rule; (3) consideration of CAA section 110(l); (4) comparison 
of the original rule to the revised SIP-approved rule; (5) the role of 
uncertainty in EPA's analysis; and (6) the types of information that 
would be particularly useful in developing a visible emissions SIP 
revision.

1. Role of Visible Emissions in NAAQS Attainment and Maintenance

    Opacity may be defined as the degree to which emissions reduce the 
transmission of light and obscure the view of an object in the 
background. 40 CFR 60.2. Opacity is important because it provides 
information regarding pollutants visible to the eye leaving an 
emissions source. In general, the more that opaque particles pass 
through an emissions point, the more light will be blocked, thus 
increasing the opacity percentage. However, variables such as the size, 
number, and composition of the particles in the emissions can result in 
variations in the percentage of opacity.
    Historically, visible emissions have been an important tool for 
implementation of PM NAAQS and, in particular, for the implementation 
and enforcement of PM limits on sources to help attain the NAAQS. 
Visible emissions have been a useful tool to indicate overall operation 
and maintenance (O & M) of a facility and its emissions control devices 
even before modern instruments that measure PM on a direct, continuous 
basis existed. The observation of greater than normal visible 
emissions, particularly on a recurring basis, has served as an 
indication that incomplete combustion or other changes to the process 
and/or the control device had or were occurring; such changes 
frequently led to increased PM emissions. Although opacity is not a 
criteria pollutant, opacity standards continue to be used as an 
indicator of the effectiveness of emission controls for PM emissions, 
or to assist with implementation and enforcement of PM emission 
standards for purposes of attaining PM NAAQS. Opacity measurements can 
serve as an indicator of a well-maintained, well-operated source and 
that such sources should be able to achieve visible emissions that 
comply with opacity limits. For example, data submitted by one 
commenter show routine source operation with opacity of about five 
percent.\6\ Conversely, visible emissions at much higher percentages 
(such as those allowed by Alabama's revised rules), particularly on a 
recurring basis, may indicate that a source is in violation of 
applicable SIP or permit mass limits as well.
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    \6\ Alabama Power Company in Attachment T from the docket shows 
that over a three-year period its units did not exceed 5 percent 
opacity for 55.4 percent of the operating time, 10 percent opacity 
for 89 percent of the operating time, and 15 percent opacity for 
97.6 percent of the operating time. In addition, the U.S. District 
Court for the Northern District of Alabama found in 2009 that at 
TVA's Plant Colbert, Units 1-4 typical baseline opacity measured 
about 5-8 percent during normal unit operation, and Unit 5 was 
projected to operate below 5 percent opacity even with a partially 
malfunctioning control device and below 10 percent ``under extreme 
conditions that are unlikely to ever occur.'' Sierra Club v. TVA, 
592 F. Supp. 2d 1357, 1367 (N.D. AL 2009).
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    Many commenters agreed that the precise relationship between 
opacity and PM emissions was uncertain. Despite this uncertainty, there 
is a general relationship between opacity and particulate matter mass 
emissions. As a result, increases in opacity can be indicative of 
changes in emissions control device performance or source operation, 
which in turn can lead to increases in mass emissions.
    Furthermore, based on the information contained in the record for 
this action and a general lack of opacity and corresponding PM 
emissions data received to date, it is apparent that the mass of 
emissions based on short-term increases in opacity cannot be quantified 
readily for each of the 19 sources affected by the SIP revisions in the 
Alabama Submittals.\7\ There are several contributors to the 
uncertainties associated with relating mass emissions to increases in 
opacity, including: (1) Differences between combustion technology 
characteristics and fuel components; (2) differences in control 
technology types, temperatures at which they operate, and load 
characteristics; (3) the recognition that both opacity and mass 
emissions are subject to significant variability over short periods of 
time and fluctuations such that one may act independently of the other; 
and (4) differences between the mass of particles that exists at the 
point of opacity measurement by the COMS (e.g., in the stack) and the 
direct PM2.5 that forms immediately upon exiting the stack 
(that are related to fuel components more than to control technology).
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    \7\ EPA specifically requested that commenters provide any 
available concurrent data showing the PM mass emissions and opacity 
for sources affected by the SIP revision at issue, but no commenter 
supplied this information. 74 FR 50934.
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2. History of Alabama's Visible Emissions Rule

    EPA first approved Alabama's visible emissions rules into the 
Alabama SIP in 1972. 37 FR 10842, 10847 (May 31, 1972). The State 
submitted the visible emissions rules as part of its SIP for attainment 
and maintenance of the total suspended particulates (TSP) NAAQS (the 
predecessor to the PM NAAQS). The State has revised these rules three 
times in support of those goals.
    Historically, Alabama has had areas with attainment problems for 
the various PM NAAQS. Originally, EPA designated some areas in Alabama 
as nonattainment for the TSP NAAQS. In 1987, EPA replaced the TSP NAAQS 
with the PM10 NAAQS, and all areas of Alabama were 
designated as attainment for those NAAQS. 56 FR 11101 and 58 FR 67734. 
All areas of Alabama remain designated attainment for the 
PM10 NAAQS. In 1997, EPA promulgated new annual and 24-hour 
particulate matter NAAQS, using PM2.5 as the indicator. 
Effective April 5, 2005, EPA designated portions of Alabama, in the 
Birmingham and Chattanooga areas, as nonattainment for the 1997 
PM2.5 NAAQS. 70 FR 944. In 2006, EPA promulgated new 
PM2.5 NAAQS, significantly tightening the 24-hour standards. 
Effective December 14, 2009, the Birmingham area was designated 
nonattainment for the 24-hour PM2.5

[[Page 18873]]

NAAQS, as revised in 2006. The Birmingham area remains designated as 
nonattainment for both the 2006 24-hour and 1997 annual 
PM2.5 NAAQS. Chattanooga remains designated as nonattainment 
for the 1997 annual PM2.5 NAAQS. Alabama's visible emissions 
rules continue to be a part of the Alabama SIP for attainment and 
maintenance of the PM NAAQS.
    The SIP revision at issue affects the applicable visible emissions 
limits at approximately 19 stationary source facilities.\8\ These 19 
facilities include older coal-fired utilities, cement manufacturing 
facilities, and pulp and paper facilities, among others. Five of these 
facilities are located in or near nonattainment areas for the current 
PM2.5 NAAQS. Specifically, Cheney Lime and Cement Company 
(Allgood), Ernest C. Gaston Electric Generating Plant (Alabama Power 
Company (APC)), and William Crawford Gorgas Electric Generating Plant 
(APC) are located within the Birmingham nonattainment area for the 1997 
annual and 2006 24-hour PM2.5 NAAQS; Bowater Incorporated 
(Westover) is located near that area. In addition, Widows Creek Fossil 
Plant (Tennessee Valley Authority (TVA)) is located in the Chattanooga 
nonattainment area for the 1997 annual PM2.5 NAAQS. Other 
facilities affected by these visible emissions rules may also impact 
these or other nonattainment areas.
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    \8\ At this time, it is EPA's understanding that the rules at 
issue apply to 19 facilities. Due to the applicability portions of 
the rule, the rule could apply to fewer facilities over time, but 
will not likely apply to any more.
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    The geographic location of affected sources covered by the visible 
emission rules in the EPA-approved SIP is relevant. This is because (as 
is discussed more fully below) EPA interprets section 110(l) to 
prohibit approval of SIP revisions that would increase emissions of 
pollutants for which an area is designated nonattainment, in the 
absence of offsetting emission reductions or an attainment 
demonstration addressing the rule changes at issue.
    Opacity remains an important tool that states and EPA rely upon in 
establishing and enforcing PM-related standards for SIPs and other 
standards promulgated under the CAA (such as New Source Performance 
Standards (NSPS) and National Emission Standards for Hazardous Air 
Pollutants). For example, opacity measurements can serve as an 
indicator of compliance with PM emissions between PM stack tests. The 
Submittals would provide sources with the flexibility to allow for 
visible emissions of up to 100 percent opacity (previous maximum 
opacity was 40 percent) for up to 2.4 consecutive hours per day \9\ 
(previous consecutive maximum time for ``exempt'' periods per day was 6 
minutes). This change, like all SIP revisions, must be consistent with 
section 110(l).
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    \9\ The Submittals allow up to 2.4 hours per day of operation at 
opacity levels in excess of 20 percent, provided that the total of 
such periods did not exceed 2 percent of operating time in a 
quarter, excluding periods of startup, shutdown, load change and 
rate change (or other short intermittent periods upon terms approved 
by ADEM's Director and included in a State-issued permit).
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3. Consideration of CAA Section 110(l) \10\
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    \10\ EPA's evaluation of this SIP revision focused on section 
110(l). If EPA were to find the revision approvable under section 
110(l) it would have to consider other issues raised by the 
commenters, including whether it is approvable under section 193. 
Further, section 110(l) applies with respect to all NAAQS in effect, 
even where EPA has not yet made designations.
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    In considering whether to approve the SIP revision at issue in this 
action, EPA must evaluate the changes embodied in the Submittals from 
the State in light of the requirements of section 110(l). Section 
110(l) of the CAA provides, in relevant part, that:

    * * * The Administrator shall not approve a revision of a plan 
if the revision would interfere with any applicable requirement 
concerning attainment and reasonable further progress (as defined in 
section 7501 of this title), or any other applicable requirement of 
this chapter.

    Congress added section 110(l) during the 1990 amendments to the CAA 
as support for the cornerstone of the SIP program in the CAA--the 
attainment and maintenance of the NAAQS. 101 Stat. 2404 (101 Pub. L. 
549) (November 15, 1990). The provision was added as part of general 
revisions to section 110 to address EPA actions on SIP revisions, in 
part responding to court cases such as a Ninth Circuit Court of Appeals 
case, Abramowitz v. EPA, 832 F.2d 1071 (9th Cir. 1987), which discussed 
Train v. NRDC, 421 US 60 (1975) (both cases addressed EPA consideration 
of SIP revisions in light of some evaluation of whether the revision at 
issue would affect the NAAQS, i.e., the impacts upon attainment or 
maintenance of the NAAQS). S. Rep. No. 101-228 (Report of the Committee 
on Environment and Public Works, United States Senate) (1990 CAA Legis. 
Hist. 8338, 8360-8363).
    By its plain language, section 110(l) applies to every SIP revision 
submitted by a state. In evaluating whether a given SIP revision would 
interfere with attainment or maintenance, as required by section 
110(l), EPA generally considers whether the SIP revision will allow for 
an increase in actual emissions into the air over what is allowed under 
the existing EPA-approved SIP. EPA has not required that a state 
produce a new complete attainment demonstration in order to make every 
revision to its SIP, provided that the status quo air quality is 
preserved. For the Submittals at issue in this action, EPA's view has 
been that if the SIP revision does not interfere with attainment or 
maintenance of the NAAQS, then it is unlikely to interfere with other 
applicable requirements. For example, if EPA concludes that emissions 
of PM allowed under the SIP are not increasing as a result of the SIP 
revision, then no additional control requirements would be required 
under section 193.
    EPA has historically interpreted section 110(l) as requiring the 
Administrator to have some basis on which to conclude that a SIP 
revision would not interfere with attainment and maintenance of the 
NAAQS, or any other applicable requirement, before EPA could approve 
the SIP revision. EPA has regularly requested such information from the 
state to support a revision, particularly where there was some 
uncertainty regarding the impacts of the SIP revision. For example, in 
2005, the State of North Carolina submitted a SIP revision that raised 
issues similar to the Alabama proposal. After considerable discussion 
between EPA and North Carolina about what revisions would be consistent 
with the requirements of section 110(l), the State submitted a SIP 
revision that addressed key issues. The rules in the revision retained 
the same number of total minutes and maximum levels of opacity allowed 
during excursion periods as under the prior EPA-approved SIP (i.e., the 
four hourly six minute exceedance periods allowed under the existing 
North Carolina SIP could occur at any time, including consecutively, 
during a 24-hour period, but the allowable maximum opacity levels 
during these periods was not increased). In particular, EPA did not 
adopt an ``average daily opacity'' approach for North Carolina, which 
would have allowed extended periods of high opacity (in excess of 40 
percent). See 70 FR 61556 (October 25, 2005). Similarly, EPA has 
proposed to disapprove a visible emissions SIP revision for Ohio in 
which that state sought to relax limitations on the number of occasions 
of excess opacity per hour, potentially allowing entire days with 
elevated opacity. The revision was submitted without a section 110(l) 
showing that the relaxation in opacity requirements would not reflect 
increased emissions

[[Page 18874]]

that would interfere with attainment and maintenance of the NAAQS or 
other requirements of the CAA. 70 FR 36901 (June 27, 2005).
    EPA recognizes that 110(l) analyses are case-specific and that the 
scope and nature of the analysis will vary, depending on the factual 
details of the SIP revision at issue. See, e.g., Hall v. EPA, 273 F.3d 
1146 (9th Cir. 2001) and Kentucky Resources Council, Inc., v. EPA, 467 
F.3d 986 (6th Cir. 2006); see also, 61 FR 16,050, 16,051 (April 11, 
1996) (actions on which the Kentucky Resources Council case were 
based).\11\ However, in the absence of a full attainment or maintenance 
demonstration, EPA has consistently required a sufficient basis in the 
record for concluding that the SIP revision would not interfere with 
attainment and maintenance of the NAAQS, or any other applicable CAA 
requirement.\12\
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    \11\ EPA's action today is consistent with both these 9th and 
6th Circuit cases addressing 110(l).
    \12\ As is discussed below, EPA's previous approval of the 
Submittals was a departure from this approach.
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4. Comparison of the Original Rule to the Revised Rule

    The substantive starting point for evaluating any SIP revision is 
to consider the differences between the current EPA-approved SIP rule 
and the revised rules being proposed by the state in the revision. Many 
of these differences were highlighted by the Petitioners and other 
parties during the public comment process on both the April 2007 
proposal and the October 2, 2009, reconsideration proposal.
    In this case, we began our analysis by comparing the rule in effect 
in the Alabama SIP at the time of EPA's April 2007 proposed action 
(hereafter ``the previous rule'') with the 2003 and 2008 Submittals 
(hereafter ``the current rule''). Under both rules, the maximum number 
of exempt six-minute periods \13\ allowed per day is the same--24; the 
maximum ``allowable average quarterly opacity'' \14\ is approximately 
the same--22 percent under the previous rule, and 21.6 percent under 
the current rule; and the maximum ``allowable average daily opacity'' 
is the same under both rules--22 percent.\15\ However, there are two 
significant differences \16\ between the previous rule and the current 
rule. The first is that the current rule allows for maximum visible 
emissions of 100 percent opacity during the exempt periods, while the 
previous rule allowed for maximum visible emissions of only 40 percent 
opacity during such periods. AAC 335-3-4-.01(4) (current rule). The 
second is that the current rule allows exceedances of the 20 percent 
SIP standard for intervals of up to 2.4 consecutive hours (i.e., up to 
24 consecutive six-minute periods per calendar day), while the previous 
rule allowed exceedances of the 20 percent SIP standard for intervals 
of only 0.1 consecutive hours (i.e., one six-minute period per 
hour).\17\ Thus, the two key differences are that the current rule 
allows for opacity to increase up to 100 percent and allows up to 2.4 
consecutive hours of opacity at that level (i.e., the ``bundling'' of 
high opacity periods) per day. A critical question, therefore, is 
whether the significant increase of the maximum allowable opacity from 
40 percent to 100 percent for such extended periods could result in 
more PM emissions were sources to take advantage of the changed limits.
---------------------------------------------------------------------------

    \13\ Unless otherwise noted, this notice refers to exempt 
periods other than those provided by the previous rule for startup, 
shutdown, load change and rate change (or other short intermittent 
periods upon terms approved by ADEM's Director and included in a 
State-issued permit), which were part of the existing SIP-approved 
rule and remained unchanged under the October 15, 2008 final action 
rule.
    \14\ ``Allowable average quarterly opacity'' is not a 
traditional measurement used by states or EPA for monitoring opacity 
or for opacity standard-setting purposes. Rather, EPA first used 
this approach, which allows sources to ``average out'' periods of 
very high opacity with periods of lower opacity, in the notice 
proposing to approve the Submittals, if the rules were changed to 
limit allowable average quarterly opacity. See 72 FR 18432 
(providing instructions for calculating ``allowable average 
quarterly opacity levels.'') Subsequently, in the notice approving 
the Submittals, EPA also used the concept of ``allowable average 
daily opacity.'' 73 FR 60958.
    \15\ See previous rule AAC 335-3-4-.01(1)(b) and current rule 
AAC 335-3-4-.01(4) and 335-3-4-.01(5).
    \16\ One of the technical support documents (TSDs) provided for 
this action explains in detail the differences between the current 
and prior visible emissions rules. EPA considered all the 
differences in reaching its decision today. EPA is simply 
identifying two significant differences that are particularly 
relevant to the analysis of the submittal.
    \17\ See previous rule AAC. 335-3-4-.01(1)(b) and current rule 
AAC 335-3-4-.01(4).
---------------------------------------------------------------------------

    In EPA's original approval notice, we adopted a limited analytical 
framework for addressing this question. We did not conclude that the 
proposed change in the SIP would not result in increased PM emissions. 
Rather, we established a new metric of ``average daily opacity'' (and 
``average quarterly opacity'') and concluded that section 110(l) did 
not prohibit approval of a SIP revision that allowed significantly 
increased opacity levels for longer consecutive periods of time because 
the revision would not increase the allowable average opacity levels 
(on either a quarterly or daily basis). This analysis was focused on 
opacity and operational conditions regarding opacity as opposed to a 
focus on the relationship between opacity and PM mass emissions, in 
part because EPA did not have any useful source-specific data regarding 
the relationship between opacity and PM mass emissions at the affected 
facilities.
    EPA also concluded that the relationship between changes in opacity 
and increases or decreases in ambient PM2.5 levels could not 
be quantified readily for the sources subject to the SIP revision, and 
was particularly uncertain for short-term analyses and that the level 
of uncertainty about whether increased opacity levels allowed under the 
revision would allow increased mass emissions was sufficiently high 
that, in the absence of additional information to confirm a change in 
emissions one way or the other, section 110(l) did not prohibit 
approval of the SIP revision.
    After reconsideration, however, EPA's position is that both of the 
findings that provided the foundation for its initial approval of the 
SIP revision were not strong enough to support approval under the CAA. 
EPA concludes that, as it was described in the Submittals, the concept 
of ``average daily opacity'' is not a useful tool for evaluating 
whether the Submittals are likely to maintain current air quality, 
particularly given the lack of other limitations on opacity exceedances 
in the Submittals. One of the primary purposes of opacity limits is to 
ensure that PM control devices are operating within normal parameters. 
Thus, larger and longer exceedances of an opacity limit (e.g., 100 
percent opacity or other high opacity levels over a longer period of 
time such as 2.4 consecutive hours), which may indicate problems with a 
control device or other significant changes in emissions, are more 
significant than shorter and smaller exceedances. Under the approach of 
the revised rule, a control device could temporarily shutdown or 
malfunction, potentially resulting in 100 percent opacity, for an hour 
or two and the source could still be in compliance with the 22 percent 
average daily limit. By contrast, an opacity limit that requires 
consistent compliance at 20 percent, and allows only one excursion of 
six minutes per hour to 40 percent opacity will limit larger and longer 
excursions.
    In addition, an opacity limit that requires consistent compliance 
at 20 percent and allows only one excursion of six minutes per hour to 
40 percent opacity helps ensure that sources and their control devices 
are properly maintained, operated, and controlled. In EPA's experience, 
a source that is properly maintained, operated and

[[Page 18875]]

controlled should be capable of meeting the opacity requirements of the 
Alabama SIP without this revision. EPA is concerned that the allowance 
of higher levels and longer consecutive durations of opacity 
exceedances, even with an ``average daily opacity'' cap, would 
undermine an important purpose of the opacity limit, to ensure proper O 
& M of sources and their control devices.
    After reviewing the issues raised in the petition for 
reconsideration and additional information received during the 
reconsideration public comment period, EPA concludes that the approach 
utilized to evaluate the Submittals in the October 15, 2008, rulemaking 
resulted in a fundamentally incomplete analysis. Requiring a source to 
maintain an average daily opacity of 22 percent does not provide 
assurance that the source will generally achieve the same level of PM 
control (and emissions) as a source which meets a limit of 20 percent 
opacity, except for one six-minute period per hour at 40 percent. 
Accordingly, the approach of the prior notice, which focused solely on 
maintaining an overall average daily (and quarterly) opacity does not 
provide an adequate framework for assessing the impact of the 
Submittals on emissions and air quality, which is the touchstone of the 
analysis required under section 110(l).
    EPA did receive modeling from a variety of sources (which is 
discussed in the Response to Comments portion of today's action, 
beginning with Comment 19) which attempt to show the impact on air 
quality from the changes to the opacity requirements in the Submittals. 
In addition to EPA's discussion in the Response to Comments section, 
EPA's Technical Support Document addressing the modeling identifies the 
information gaps that prevented EPA from conducting the type of source-
specific analysis that would be necessary for completion of an adequate 
110(l) evaluation. For example, elements that are missing from the 
submitted modeling include: data from all the sources and source 
categories affected by the Alabama Submittals; a demonstration of the 
relationship between PM emissions and opacity at a particular facility 
and source-category; consideration of emissions from other sources in 
the modeled area; condensable PM data; explanation for background PM 
levels used in the evaluation; and an explanation of the use of 
PM10 as a surrogate for PM2.5; among other 
concerns. As EPA noted in its evaluation of modeling submitted during 
the first comment period:

    Although source-specific correlations between opacity and mass 
emissions can be established for some sources, none have been for 
the sources subject to this SIP revision and therefore assumptions 
must be made about how a change in the opacity rule might affect the 
level of PM mass emissions being modeled. These assumptions made 
about the relationship drive model results and, thus, are important 
in evaluating the result of the modeling exercise.

73 FR 60961. EPA has carefully reviewed all of the modeling submitted 
and has concluded that, without source-specific data on the mass-
opacity relationship, there is not an adequate basis to model the 
impact of the revisions to the opacity rules on PM mass emissions. 
Therefore, the models are insufficient and too inaccurate to provide a 
basis for concluding that the Submittals satisfy the requirements of 
section 110(l). As discussed below, EPA would need additional data and 
information before it could conclude that this approach would not 
result in an increase of nonattainment pollutants that would interfere 
with attainment and maintenance of the NAAQS.

5. The Role of Uncertainty in EPA's Analysis

    As was noted earlier, a key issue in evaluating the Submittals is 
the element of uncertainty in the relationship between opacity and PM 
mass emissions. Many SIP submittals involve some level of uncertainty. 
EPA has never, and does not now, take the position that a small 
possibility that an attainment SIP might turn out not to result in 
attainment of the NAAQS, or to prevent a violation of the NAAQS, or 
that a SIP revision might worsen air quality, necessitates denial of a 
SIP revision. EPA recognizes that attainment planning generally 
requires a high degree of technical judgment, and often involves some 
degree of uncertainty. In EPA's prior approval, we concluded that the 
level of uncertainty concerning the impact of the SIP revisions on 
emissions of PM from sources was so great that EPA could not make a 
technical judgment as to whether or not approval of the Submittals 
would likely interfere with attainment and maintenance of the NAAQS or 
any other applicable requirements. In the face of such uncertainty, EPA 
concluded that section 110(l) did not prohibit the approval of the 
revisions at issue. After reconsideration, EPA has concluded that its 
traditional, and more precautionary, approach to interpreting section 
110(l) is appropriate.
    There is a general relationship between opacity and PM emissions 
such that an increase in opacity means the concentration of smaller 
particles, larger particles, or both, increases. See, e.g., Malm, 
William C., ``Introduction to Visibility,'' Cooperative Institute for 
Research in the Atmosphere, May 1999 at Chap. 2, p. 8. However, because 
increases in the quantity of smaller particles may be accompanied by 
decreases in the quantity of larger particles, and vice versa, changes 
in opacity do not necessarily reflect corresponding changes in the mass 
of PM emissions. While source-specific relationships between opacity 
and PM emissions may be obtained through testing, they can be 
influenced by a variety of circumstances such as fuel compositions and 
types of equipment malfunction that may occur. Therefore, while changes 
in opacity generally indicate changes in PM emissions, there is 
uncertainty about quantifying the specific level of PM emissions 
associated with varying levels of opacity.
    EPA has previously explained the elements of that uncertainty in 
its proposed reconsideration action. 74 FR at 50933. One key element is 
the recognition that both opacity and mass emissions are subject to 
significant variability of short periods of time and fluctuations such 
that one may act independently of the other. Id. Thus, EPA concludes 
(and many commenters also acknowledged) that there is a relationship 
between opacity and PM such that periods of high opacity can result in 
increased PM emissions, which in turn can cause or contribute to a PM 
NAAQS violation. We can say with certainty that periods of high opacity 
would cause interference with the PM NAAQS in some circumstances. What 
EPA does not know is precisely when such changes in opacity would cause 
the interference, particularly for a variety of source types. This is 
the unknown element discussed in detail in EPA's proposal and this 
final action.
    Section 110(l) was intended to allow SIP revisions in the absence 
of full attainment demonstrations, but EPA's view is that Congress 
would not have wanted EPA to approve SIP revisions where EPA lacked not 
only an attainment demonstration but also any basis for concluding that 
the SIP revision would not interfere with attainment or maintenance of 
the NAAQS, and other applicable requirements. Accordingly, consistent 
with our past practice in considering SIP revisions, EPA concludes that 
there must be either a contemporaneous attainment demonstration or some 
other basis for concluding that a SIP revision will not interfere with 
attainment, and that uncertainty alone is not a sufficient

[[Page 18876]]

basis for approving a SIP revision. Moreover, EPA has also concluded, 
following reconsideration, that there is a sufficient likelihood that 
the SIP revision at issue in this action could allow increased mass 
emissions over what would have been allowed under the previously 
approved SIP rule and that, in the absence of additional information or 
limitations, the revision is not approvable under section 110(l). As 
noted by commenters during the reconsideration process, although a 
precise correlation between mass emissions and opacity for an 
individual source can be difficult to ascertain, the changes 
contemplated in the Submittals are such that changes in emissions, 
including increases, are possible under the opacity levels allowed by 
the SIP revision. Given the location of affected sources within 
nonattainment areas, EPA has concluded that additional emissions from 
such sources would interfere with attainment and maintenance of the 
NAAQS in these areas.
    EPA recognizes that there are circumstances in which a source will 
record opacity levels in excess of a 20 percent standard without 
necessarily increasing its mass emissions, but there are also many 
circumstances where increased opacity levels are associated with 
increased mass levels. The Submittals would provide sources with the 
flexibility to allow for visible emissions of up to 100 percent opacity 
for up to 2.4 consecutive hours per day. The degree of operational 
flexibility associated with the Submittals is such that EPA concludes 
that the opacity limits in the Submittals are likely overall to allow 
increased PM emissions. Even though every instance of operation at 
greater than 20 percent opacity may not result in increased emissions, 
and though EPA cannot precisely quantify the effect of approving the 
Submittals on the information in the record, it is reasonably 
foreseeable that approving the Alabama Submittals would allow increased 
mass emissions, for at least some sources and under at least some 
conditions, over the PM emission levels that would have been allowed 
under the previously approved SIP rule. Given this situation, section 
110(l) requires disapproval of the Submittals absent additional 
limitations which would significantly diminish the likelihood that mass 
emissions increases will occur. The result of the disapproval is simply 
that Alabama's previous EPA-approved visible emissions rule will become 
the federally-enforceable rule in the SIP (although EPA urges that 
Alabama take any regulatory action necessary to avoid having a State-
effective rule that is different from the SIP-approved rule).

6. Information Regarding Development of Visible Emissions SIP Revisions

    In EPA's October 2, 2009, reconsideration proposal following 
reconsideration, EPA included a section entitled, ``III. What 
Additional Information Would EPA Like To Receive?'' 74 FR 50934. EPA 
specifically requested information on the nature of the relationship 
between opacity and PM mass emissions over both the short and long term 
and when the opacity and PM mass emissions may have a predictable 
relationship to one another. Id. EPA also requested source-specific 
data from Alabama facilities affected by the Submittals. EPA also 
included a bulleted list of more specific types of information that 
could assist in conducting an analysis on the impacts of a SIP revision 
on the air quality of the affected area (i.e., a 110(l) analysis). Id. 
Providing guidance on development of a general visible emissions SIP 
revision is difficult because opacity and visible emissions are most 
easily evaluated in a source-specific context. However, states may 
consider the following information useful.
    As a general matter, states may find it instructive to look at 
visible emissions SIP revisions that EPA has approved. An example is 
the North Carolina approval previously referenced in this rulemaking. 
70 FR 61556. As was noted earlier in this rulemaking, there are two key 
differences between the North Carolina action and the Alabama 
Submittals now being disapproved. First, the North Carolina action did 
not allow additional minutes of opacity exceptions. Second, the North 
Carolina action did not change the percentage of opacity allowed during 
the exception periods.
    More generally, EPA expects that providing assurance that a source 
will comply with a rule that allows no more than one 6-minute 
exceedance per hour and opacity readings no greater than 40 percent 
clearly requires more effective control equipment and/or operating 
procedures than it takes to assure a source will comply with a rule 
that allows longer consecutive periods of exempt opacity excursions and 
at higher opacity levels. Opacity and PM emissions are related closely 
enough that control equipment effective enough to meet the more 
stringent opacity standard (in terms of the number of consecutive 
excursions allowed and the level of opacity excursions allowed) will 
also provide a greater level of PM emissions control. Due to the 
importance of first understanding the relationship between opacity and 
PM emissions at the affected sources, source-specific SIP revisions 
have historically been used by most states in developing different 
visible emissions standards for a source, particularly when those 
standards are less stringent than existing standards. Source-specific 
SIP revisions allow for the ability to analyze the PM/opacity 
relationship and establish an appropriate opacity limit that will not 
impact the NAAQS. The technical analysis for such rule changes would 
likely involve collection of parallel mass and opacity data for the 
source in question. If that information indicates that there will be 
increases in PM mass emissions or opacity, then further analysis would 
be required to ensure that the increased emissions associated with the 
increased opacity (or rule change at issue) will not interfere with 
attainment, reasonable further progress, or any other applicable 
requirement of the CAA (the 110(l) factors), for that particular source 
and locale. Further, a more definitive modeling assessment of the 
effect of any proposed rule would include the representative range of 
emission rates and/or conditions producing 100 percent opacity for each 
type of source affected by the rule.
    When source-specific information is available, the uncertainty 
about the relationship between opacity and mass, and the implication of 
the changes in opacity on PM emissions, is reduced and there may be a 
basis upon which to make an informed judgment about the impacts of the 
change with respect to section 110(l). Further, source-specific actions 
are much more discrete since they typically apply at a particular unit 
of a particular facility, thus eliminating the need to evaluate the 
statewide impact of the change. EPA has undertaken source-specific 
opacity revisions. See, e.g., 66 FR 33027 (June 20, 2001) (approving a 
source-specific revision affecting 14 units in Alaska). Similarly, a 
focus on a particular source category may also allow for more specific 
understanding regarding the relationship between opacity and PM 
emissions at the affected facilities and the rule's overall impact to 
air quality. 73 FR 36485 (June 27, 2008) (proposing disapproval of 
source-category specific revision; notice explains how a source-
category revision may be developed).
    EPA is not suggesting that every revision to an opacity standard 
requires source-specific analyses. If a submission provides a 
sufficient basis for EPA to conclude that changes to a visible 
emissions requirement will not result in

[[Page 18877]]

increased PM emissions in a nonattainment area over what would have 
been allowed under the previously approved SIP rule (or otherwise 
interfere with any applicable requirement of the CAA), then EPA 
anticipates that it would be approvable under section 110(l). 
Ultimately, the key issue that must be addressed in any 110(l) analysis 
of an opacity SIP revision is an evaluation regarding the impact of 
that revision on PM emissions and the NAAQS. As was noted earlier, 
because Alabama's Submittals were voluntary revisions to the SIP and 
not mandated, Alabama has no obligation to develop another visible 
emissions revision.

III. Response to Comments

    The following are EPA's responses to the significant adverse 
comments on EPA's October 2, 2009, proposal. EPA is obligated to 
respond to adverse comments received and thus, has reviewed the 
comments that were adverse to a disapproval of the State's SIP 
revisions. EPA is now responding to those comments. Many of the 
comments overlapped or were redundant, so in order to assist with 
readability of the responses, we have organized the comments and 
responses into subject-matter groupings identified below.

1. Basis for Reconsidering the 2008 Final Action
2. Relationship Between Opacity and PM Emissions
3. Modeling
4. Relative Stringency of Previous Rule (Pre-2008 Final Action) to 
Current Rule (Post-2008 Final Action)
5. Attainment and Maintenance of the PM NAAQS (PM10 and 
PM2.5) and Data Submitted in Response to October 2009 
Reconsideration Proposal
6. Impact of Uncertainty in These SIP Revisions
7. Applicability of CAA Sections 110(l) and 193 to This Action
8. CAA Section 110(l) ``Demonstration'' of Non-Interference With the 
NAAQS and Other Requirements
9. Use of COMS and Need for Exemptions
10. Relationship of SIP Revisions to 40 CFR Section 51.212
11. Relationship of SIP Revisions to the Compliance Assurance 
Monitoring (CAM) Rule
12. Relationship of SIP Revisions to Sierra Club v. EPA, 551 F.3d 1019 
(D.C. Cir. 2008), and the Vacatur of Certain Provisions in 40 CFR Part 
63
13. Relationship of SIP Revisions to Reasonably Available Control 
Technology (RACT)
14. Other Exemptions in the Alabama SIP Related to Visible Emissions

1. Basis for Reconsidering the 2008 Final Action

    Comment 1. Commenters argued that because EPA's October 2, 2009, 
reconsideration proposal notice did not select an option, or at least 
disclose to the public which option EPA preferred, EPA's interpretation 
of the relevant CAA provisions and their application to the situation 
here will be entitled to no deference upon judicial review. Also, the 
commenters asserted that their ability to comment on the proposal is 
hamstrung by EPA's failure to articulate which option EPA would choose.
    Response 1. EPA does not agree with commenters' characterization of 
the October 2, 2009, proposed rulemaking. That proposal described two 
alternative actions in detail--including the technical, legal, and 
policy bases for each of the respective actions. EPA provided 
sufficient information for each alternative for commenters to 
participate meaningfully and for either alternative proposal to be 
finalized, depending upon what additional information was developed as 
a result of the reconsideration. EPA has previously used the 
alternative proposal option when dealing with a particularly complex 
rulemaking (see, e.g., proposal regarding California-Imperial Valley 
Planning Area, 66 FR 42187 (August 10, 2001)). In this case, EPA's 
interest in ensuring public comment on the two primary options was best 
achieved through the alternative proposals. There is no indication of 
any commenter being unable to provide meaningful comments. Numerous 
commenters provided substantive comments on both of the two proposals. 
The substance of the commenters' own comments reflect that they were on 
notice of the factual and legal issues relevant to the reconsideration.
    Comment 2. Commenters asserted that there is no new record evidence 
provided by EPA, Petitioners, or other interested parties in order to 
support the second petition for reconsideration of EPA's approval of 
the SIP revision in the October 2008 final action.
    Response 2. EPA's authority to reconsider a SIP rulemaking derives 
from both the Administrative Procedures Act (APA) section 553(e) as 
well as authority in the CAA. The APA provides the opportunity for any 
person to ``petition for the issuance, amendment, or repeal of a 
rule.'' 5 U.S.C. 553(e). The APA does not explicitly limit this right 
based on new evidence or any other limitations alleged by commenter. 
Even if there were such a limitation, EPA disagrees that the second 
petition for reconsideration did not raise issues that warranted 
reexamination of the factual and legal basis for the October 2008 
action.
    Comment 3. Commenters argued that the CAA does not authorize EPA to 
continue to entertain petitions for reconsideration ``indefinitely'' 
after a specific CAA process has been followed and reconsideration has 
been denied. According to the commenters, the CAA allows EPA to 
``call'' an approved State SIP for legal deficiencies, but does not 
allow EPA to continue to reconsider its actions on a state-submitted 
SIP revision after the revision is approved. Commenters also argued 
that EPA lacks authority to reverse its approval of the SIP revisions 
because EPA may only change its standard for review of SIP revisions 
under section 110(l) prospectively--i.e., EPA may only apply an 
allegedly new reading of section 110(l) to new state requests for SIP 
revision. The commenters further argued that any request for 
reconsideration of a final SIP approval must follow the procedures 
identified in CAA section 110(k)(5) for seeking a change to a 
previously approved SIP revision (noting that section 307 does not 
apply and section 553(e) of the APA cannot be used to bypass 110(k)).
    Response 3. EPA disagrees with the commenters' views of EPA's 
authority to reconsider rulemakings under these circumstances. An 
administrative agency has the authority to reconsider its decisions, 
unless Congress specifically limits the agency's discretion to do so. 
See, e.g., Gun South, Inc. v. Brady, 877 F.2d 858, 862 (11th Cir. 1989) 
(holding that agencies have implied authority to reconsider and rectify 
errors even though the applicable statute and rules do not provide 
expressly for such reconsideration). The DC Circuit Court recently 
affirmed this authority in New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 
2008), where it explained that an agency normally can change its 
position and reverse a prior decision but that in the case before it, 
Congress limited EPA's ability to remove sources from the list of 
hazardous air pollutant source categories, once listed, by requiring 
EPA to follow the specific delisting process at CAA section 112(c)(9). 
See also, e.g., Trujillo v. General Electric Co., 621 F.2d 1084, 1086 
(10th Cir. 1980) (``Administrative agencies have an inherent authority 
to reconsider their own decisions, since the power to decide in the 
first instance carries with it the power to reconsider''). EPA recently 
applied this approach in connection with California conformity

[[Page 18878]]

SIPs. EPA had approved the SIPs based on a mobile source model that was 
current at the time of EPA's approval. EPA proceeded to update the 
mobile source model, but under the previous SIP approvals, conformity 
decisions would continue to be made on the basis of those previous SIP 
approvals, and would not take into account the updates to the mobile 
source model. To remedy this problem, EPA conducted a rulemaking that 
revised the previous SIP approvals so that they were limited to the 
period before States submitted, and EPA found adequate, the mobile 
source budgets in new SIPs based upon the update of the mobile source 
model. See 74 FR 55292, 55342 (October 27, 2009) (discussing EPA's 
inherent authority to reconsider SIP actions). See also 73 FR 21528 
(August 22, 2008) (EPA final action on reconsideration of previous 
Georgia SIP action).
    The commenters questioned EPA's authority to reconsider a SIP 
action and appear to suggest that EPA's authority is limited to only a 
SIP ``call'' under section 110(k)(5) of the CAA. The SIP call process, 
however, is a distinct and separate authority that Congress has given 
to EPA for use when EPA determines that a current SIP is substantially 
inadequate to attain or maintain compliance with the CAA requirements. 
See, e.g., Sierra Club v. Georgia Power Company, 443 F.3d 1346, 1348 
(11th Cir. 2006) (describing the separate revision provisions under the 
CAA and the SIP call process generally). The SIP call process was not 
intended to be the sole means of revising the SIP and does not displace 
EPA's authority to reconsider its approval.\18\ While the two processes 
may be complementary, the authority to reconsider an action and the 
authority to issue a SIP call are not mutually exclusive, and one or 
the other may be appropriate in different circumstances.
---------------------------------------------------------------------------

    \18\ In addition to its SIP call provisions, the CAA also 
includes provisions for the correction of errors in the SIP. See CAA 
section 110(k)(6). EPA notes that the process it has used for 
reconsidering and disapproving this SIP revision is entirely 
consistent with the process required under section 110(k)(6).
---------------------------------------------------------------------------

    As the commenters correctly noted, EPA's approval of a SIP revision 
is not subject to the rulemaking requirements of the CAA section 307(d) 
because it does not fall within the enumerated categories in section 
307(d)(1) of the CAA. Section 307(b)(1), to which a SIP revision 
rulemaking is subject, contemplates the ``filing of a petiti