18870 Federal Register / Vol. 76, No. 66 / Wednesday, April 6, 2011 / Rules and Regulations 

1The 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. 

2PM 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 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 51 

Requirements for Preparation, 

Adoption, and Submittal of 

Implementation Plans 

CFR Correction 

In Title 40 of the Code of Federal 

Regulations, Parts 50 to 51, revised as of 

July 1, 2010, on page 265, in § 51.166, 

paragraph (b)(49)(vi) is added to read as 

follows: 

§ 51.166 Prevention of significant 

deterioration of air quality. 

* * * * * 

(b) * * * 

(49) * * * 

(vi) Particulate matter (PM) emissions, 

PM2.5 emissions, and PM10 emissions 

shall include gaseous emissions from a 

source or activity which condense to 

form particulate matter at ambient 

temperatures. On or after January 1, 

2011 (or any earlier date established in 

the upcoming rulemaking codifying test 

methods), such condensable particulate 

matter shall be accounted for in 

applicability determinations and in 

establishing emissions limitations for 

PM, PM2.5 and PM10 in PSD permits. 

Compliance with emissions limitations 

for PM, PM2.5 and PM10 issued prior to 

this date shall not be based on 

condensable particular matter unless 

required by the terms and conditions of 

the permit or the applicable 

implementation plan. Applicability 

determinations made prior to this date 

without accounting for condensable 

particular matter shall not be considered 

in violation of this section unless the 

applicable implementation plan 

required condensable particular matter 

to be included. 

* * * * * 

[FR Doc. 2011–8334 Filed 4–5–11; 8:45 am] 

BILLING CODE 1505–01–D 

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. 

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 Stateeffective 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 http:// 

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 http:// 

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 


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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. 

3The 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. 

4The 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 renotice 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. 

5With 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 

Continued 

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 sixminute 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. 

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. 

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 


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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. 

6Alabama 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). 

7EPA 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. 

(January 3, 2005); 70 FR 28429 (May 18, 

2005) (previous rulemaking actions 

addressing section 110(l)). 

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 nongovernmental 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, welloperated 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. 

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). 

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


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8At 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. 

9The 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). 

10EPA’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. 

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. 

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). 

3. Consideration of CAA Section 

110(l) 10

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 


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11EPA’s action today is consistent with both 

these 9th and 6th Circuit cases addressing 110(l). 

12As is discussed below, EPA’s previous approval 

of the Submittals was a departure from this 

approach. 

13Unless 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. 

15See previous rule AAC 335–3–4–.01(1)(b) and 

current rule AAC 335–3–4–.01(4) and 335–3–4– 

.01(5). 

16One 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. 

17See previous rule AAC. 335–3–4–.01(1)(b) and 

current rule AAC 335–3–4–.01(4). 

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

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. 

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 sourcespecific 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 


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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 sourcespecific 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 sourcespecific 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 


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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 EPAapproved 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 Stateeffective 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 sourcecategory 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 


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Federal Register / Vol. 76, No. 66 / Wednesday, April 6, 2011 / Rules and Regulations 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 subjectmatter 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 


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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). 

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. 

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 petition for 

reconsideration by the Administrator of 

any otherwise final rule or action.’’ 42 

U.S.C. 7607(b)(1). Courts have also 

found that EPA must follow the 

rulemaking requirements of the APA 

when evaluating a SIP submission (see, 

e.g., Hall, 273 F.3d at 1161), including 

section 553(e). Finally, the very nature 

of a SIP is that it is not a static 

document; it is regularly revised to 

account for new EPA standards and new 

emissions reduction technologies. 42 

U.S.C. 7410(a)(2)(H). 

Furthermore, EPA notes that the SIP 

revision at issue did not take effect by 

its own terms until after the date on 

which EPA granted the second petition 

for reconsideration. No sources affected 

by the revisions to the Alabama SIP 

should have been required to alter their 

facilities or their operations in reliance 

on the prior EPA approval. EPA’s view 

is that a source that is properly 

maintained, operated and controlled 

should have no difficulty complying 

with either the pre-existing or the 

revised version of visible emissions 

rules in the SIP, or even complying 

simultaneously with both versions of 

the SIP, which suggests that the 

reconsideration process should not have 

been disruptive for any source. In the 

present case, EPA concluded that 

reconsideration of its approval of the 

Submittals was necessary to ensure that 

the final decision was consistent with 

the plain text and legislative history, 

and air quality goals of the CAA, given 

the facts at issue in this situation. While 

the result of EPA’s action today is that 

Alabama’s Submittals are disapproved, 

the effective date for such disapprovals 

will be the effective date of this final 

action. Thus, there is nothing retroactive 

about today’s final action. 

Comment 4. Commenters argued that 

if EPA reverses its approval of the 

Submittals now, that would be arbitrary, 

contrary to EPA’s statutory authority 

and its responsibility to implement the 

CAA, and in violation of EPA’s 

‘‘delegation commitment’’ to Alabama 

under the CAA. 

Response 4. As a point of 

clarification, Alabama is authorized to 

implement certain portions of the CAA 

through its SIP. Commenters do not 

explain the ‘‘delegation commitment’’ 

reference. Such terminology is 

inapposite as the majority of CAA 

programs are ‘‘authorized,’’ not 

‘‘delegated,’’ particularly with regard to 

those embodied in a SIP. Some CAA 

programs, such as section 112, are 

routinely ‘‘delegated’’ by EPA to states; 

however, section 112 programs are not 

SIP programs. EPA’s responsibility to 

implement the CAA extends to ensuring 

that its decisions are based in the CAA 

and its implementing regulations. In the 

instant action, EPA is reversing a 

previous approval decision because 

after reconsideration, EPA has 

concluded that a disapproval is required 

based on known technical information 

(as opposed to uncertainty) and an 

interpretation of section 110(l) 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. As was explained above, EPA’s 

reconsideration process is well 

grounded in statutory authority. 

Comment 5. Commenters asserted that 

EPA’s reconsideration proposal notice 

does not provide any information about 

the legal authority that the Agency 

believes justifies its action. The 

commenters further argued that it is 

incumbent upon the Agency to disclose 

the legal basis upon which it proposes 

to act and to provide the public with the 

opportunity to comment on that 

asserted basis, and that without such an 

explanation from EPA, the October 2, 

2009, proposal notice is deficient and 

does not provide an adequate basis 

upon which the Agency can lawfully 

take action. 

Response 5. EPA does not agree with 

commenters’ assessment. The October 2, 

2009, reconsideration proposal includes 

two alternative options for final action— 

both based upon application of section 

110(l) of the CAA. Section 110(l) applies 

to all SIP revisions and limits EPA’s 

legal authority to approve revisions to 

existing EPA-approved SIP provisions. 

The reconsideration proposal notice 

explained the alternative proposed 

actions as well as the interpretation of 

section 110(l) that would support each 

of the alternatives. The substance of the 

comments reflects that the commenters 

were in fact on notice of the factual and 

legal issues that EPA raised for 

reconsideration. 

Comment 6. Commenters asserted that 

certain documents received in response 

to a Freedom of Information Act (FOIA) 

request do not support the reopening of 

the public comment period. 

Response 6. As was explained earlier, 

there is no prohibition on EPA’s 

authority to review a final action and 

allow for a new public comment period 

on that action. EPA has provided the 

basis of the reconsideration of the 

October 15, 2008, final rule—the CAA 

and the APA. Whether documents 

obtained through a FOIA support EPA’s 

reconsideration, in the opinion of the 

commenter, is not relevant. 

Comment 7. Commenters asserted that 

EPA appears to be considering a ‘‘policy 

change’’ in how it interprets and applies 

section 110(l) in the reconsideration 

process. Commenters argued that if EPA 

wants the State to amend its approved 

SIP to reflect revised EPA policy on 

section 110(l), EPA must act under 

section 110(k)(5) of the CAA and not 

through a ‘‘unilateral’’ notice and 


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19EPA notes APC’s request that should EPA take 

final acting disapproving Alabama’s SIP revisions, 

that EPA stay its disapproval action pending 

litigation (APC Comments, pp. 10, footnote 2). EPA 

is not acting on this request through this final 

action. 

comment process. Commenters asserted 

that they are aware of no other situation 

where EPA has proposed to act in this 

manner to ‘‘withdraw’’ a final approval 

of a SIP revision.19

Response 7. EPA’s interpretation of 

110(l) that is outlined in this final action 

is consistent with EPA’s historic 

interpretation of 110(l), the plain text of 

the CAA, and the legislative history of 

the CAA (as well as court opinions that 

have considered 110(l)). EPA’s decision 

is based on its re-evaluation of the 

likelihood that approval of the 

Submittals will result in increases of 

allowable PM emissions. In amending 

its previous action, EPA is placing 

greater weight on the technical aspects 

of the SIP Submittals that are known to 

have the potential for adverse impacts 

on the NAAQS as a result of allowing 

greater levels and durations of opacity 

exceedances. This change does not 

represent a policy shift, but rather, an 

analytical reconsideration of what 

decision is most supported by the CAA, 

given the facts at issue in this 

rulemaking. Moreover, EPA’s 

reconsideration process in this action 

was far from ‘‘unilateral.’’ By reopening 

the rulemaking for additional public 

comment, and setting forth the legal, 

technical, and policy bases for that 

alternative outcomes in the 

reconsideration process, EPA sought to 

ensure that the public had an 

opportunity to comment and review the 

possible options. 

Ironically, if anything, the SIP call 

process apparently preferred by 

commenters is more ‘‘unilateral’’ in that 

such a process is initiated after EPA has 

concerns that an existing SIP is 

substantially inadequate and often 

requires a state to take action to revise 

its SIP following EPA’s final action on 

the SIP call. Here, EPA’s disapproval 

will result in a rule coming back into 

effect that was in effect for years. 

Alabama will not be required to submit 

a revised SIP revision. Further, as 

explained above, EPA has used the 

alternative proposal approach in the 

past. While the approach is not 

appropriate in all regulatory actions, it 

serves an important purpose of seeking 

public comment in the unusual 

circumstance in which two potentially 

supportable decisions exist and 

additional information or input from the 

public may be helpful to EPA in making 

a final decision. 

Comment 8. Commenters stated that 

EPA’s prior analysis of the SIP revision 

remains sound and that there is no basis 

for reversing the conclusions of that 

analysis. According to the commenters, 

the rigors of the prior SIP revision 

process insured that the concerns raised 

by the Petitioners have already been 

heard and considered by both ADEM 

and EPA multiple times. The 

commenters argued that the petition for 

reconsideration raised no issues that 

were not or could not have been raised 

during the prior rulemaking process. 

Therefore, the commenters argued that 

reversing the prior approval of 

Alabama’s Submittals at this point and 

in this manner would not only be an 

abuse of EPA’s authority under the 

CAA, it would be the height of arbitrary 

and capricious Agency action. 

Response 8. EPA does not agree with 

the commenters’ assessment. For the 

reasons described in this final notice, 

EPA has determined that reconsidering 

its prior approval and seeking 

additional notice and comment on the 

factual and legal issues raised by the 

Petitioners was an appropriate action. In 

reversing its prior approval, EPA has 

concluded that disapproval is necessary 

pursuant to the plain text of the CAA, 

its legislative history, and the air quality 

goals described therein. EPA appreciates 

that there has been substantial 

discussion about the merits of the 

Submittals, including various 

opportunities for public comment. 

Ultimately, however, when weighing 

alternatives, EPA’s final decision must 

be the one that is most consistent with 

the CAA, even if that decision is 

reached through a reconsideration 

process. EPA has already addressed its 

authority to review the October 15, 

2008, final action in response to 

comments above. 

Comment 9. Commenters asserted that 

in granting the second petition for 

reconsideration and re-opening the 

rulemaking for further public comment, 

EPA ignores the lack of a legal basis for 

reconsideration, its earlier rejection of 

AEC’s arguments for reconsideration on 

the merits, and its thorough review and 

technical analysis of the effect of these 

SIP revisions during the earlier 

rulemaking itself. According to the 

commenters, reconsidering a SIP 

approval sets a poor precedent and 

undermines regulatory certainty and the 

integrity of EPA’s rulemaking processes. 

Response 9. EPA does not agree with 

commenters’ assessment. To the 

contrary, the reconsideration process 

has ensured that EPA has left no issue 

unconsidered in its analysis of the 

Submittals. EPA’s final action on the 

Submittals, while amended from its 

previous action, is strongly grounded in 

the CAA, the APA, and sound science. 

This action furthers the purposes of the 

CAA, is based on the substantive 

requirements of the CAA, and follows 

the rulemaking requirements of the CAA 

and the APA. Thus, the action supports 

regulatory certainty and the integrity of 

SIP process. See, e.g. 73 FR 21528 

(August 22, 2008) (EPA reconsideration 

of Georgia SIP action). Indeed, the fact 

that the CAA and the APA provide 

bases for reconsidering regulatory 

decisions demonstrates that Congress 

expected EPA to take necessary action 

to revise its actions when a party raises 

factual or legal issues that the Agency 

finds justify reconsidering such actions. 

Comment 10. Commenters questioned 

why EPA granted the petition for 

reconsideration of the approval of 

Alabama’s Submittal because the 

Petitioners have provided no new 

information. 

Response 10. As was discussed above, 

the APA does not restrict EPA’s 

authority to reconsider a rule to a 

specific record or timeframe. EPA was 

petitioned for reconsideration of a rule 

and EPA granted that reconsideration 

because it concluded that the petition 

raised factual and legal issues that 

justified further evaluation. The second 

petition for reconsideration raised 

numerous reasons why EPA’s October 

15, 2008, final action should be 

reconsidered, including several reasons 

not identified in the first petition for 

reconsideration. Thus, commenters’ 

characterization of the second petition 

for reconsideration as providing no new 

information is also not correct. 

2. Relationship Between Opacity and 

PM Emissions 

Comment 11. Commenters asserted 

that data submitted to EPA show that 

there is no reliable or direct correlation 

between opacity and PM emissions. In 

addition to several sources of 

uncertainty in the relationship between 

changes in opacity and increases or 

decreases in PM2.5 levels cited by EPA 

in the April 12, 2007, proposal notice, 

the commenters argued that other 

variables affecting the relationship of 

opacity and PM mass emissions include 

stack diameter, stack gas temperature, 

particle density (a function of coal type), 

and flue gas water vapor content. The 

commenters argued that many, if not 

most, of these variables are beyond the 

control of source operators. Therefore, 

the commenters stated that while 

opacity can serve as an indicator of 

whether the boiler and related pollution 

control equipment at a specific source 

are well-controlled and well-operated, 

changes to opacity of emissions, 


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including changes to the SIP limits 

applicable to opacity in a SIP, cannot be 

presumed to have any direct effect on 

ambient concentrations of PM. 

Response 11. EPA generally agrees 

with commenters that there is inherent 

uncertainty in the precise relationship 

between opacity and ambient 

concentrations of PM, although we note 

that some variables are less likely to 

vary during a single source’s operation 

(as opposed to among different sources). 

EPA also agrees (as a general matter) 

with commenters’ statements that 

opacity is useful as an indicator of a 

source’s operations and control 

technology. Moreover, opacity can be a 

reliable indicator of PM emissions when 

appropriate source-specific testing is 

carried out and correlations are 

established for the particular source, 

operating characteristics, and fuel 

supply. 

EPA disagrees, therefore, that 

increases in opacity of emissions per se 

could not reflect any increases in mass 

emissions under any circumstances, in 

particular in the case of the significant 

increases in the percentage opacity and 

the duration of excursion time at issue 

in these SIP revisions. This comment 

highlights the importance of ensuring 

that the final decision made by EPA to 

approve a SIP revision is based on a 

reasoned application of that knowledge 

within the confines of the CAA. 

Comment 12. Commenters argued that 

available data continue to demonstrate 

there is no reliable, generally applicable 

relationship between opacity and the 

PM NAAQS. The commenters asserted 

that previous technical studies 

submitted by APC in the rulemaking 

confirm this lack of correlation. The 

commenters referred to prior comments 

for the assertion that: ‘‘Because opacity 

is dependent on so many factors, there 

is no general relationship between 

opacity and particulate loading.’’ 

Response 12. EPA agrees that opacity 

data from different individual sources 

are very specific to the source and to the 

manner in which it is being operated for 

the period over which data is collected. 

In other words, source operation affects 

data produced by the source. Thus, EPA 

and others must consider not only the 

data on opacity and PM, but also the 

details regarding the facility and its 

operating characteristics as part of 

developing an opacity/PM correlation. 

As a result, such data from one facility 

may be of limited value in extrapolating 

reliable conclusions about emissions 

from another facility. However, EPA 

expects that sufficiently high increases 

in opacity up to 100 percent for 

extended periods can represent some 

impact on PM emissions from the 

sources affected by the rules at issue in 

the Alabama SIP revisions. As noted by 

comments received through the 

reconsideration process, although the 

precise correlation between the mass 

and opacity of emissions may vary, 

significant increases in opacity to its 

highest measurable level at the same 

source are likely to result in additional 

PM emissions from that source. Given 

that several sources are located in and 

near nonattainment areas, such 

additional emissions are inconsistent 

with the prohibition of section 110(l) on 

SIP revisions that will interfere with 

attainment and maintenance of the 

NAAQS. 

Comment 13. One commenter 

asserted that EPA’s prior conclusion 

that greater opacity does not necessarily 

mean greater PM emissions is entirely 

reasonable. 

Response 13. EPA appreciates 

commenters’ position on this issue—the 

uncertainty inherent in the relationship 

between opacity and PM is discussed at 

length in this final action. While EPA 

agrees that greater opacity does not 

necessarily (in all circumstances) mean 

greater PM emissions, EPA does expect 

that some periods of greater opacity 

(particularly of high opacity for longer 

periods of time) are likely in at least 

some circumstances to be accompanied 

by greater PM emissions. 

Comment 14. A commenter agreed 

that it is difficult to accurately 

characterize differences in direct PM2.5

emissions attributable to short-term 

increases in opacity and further 

commented that: (1) The type of event 

causing the short-term increase in 

opacity will most probably have an 

effect on any direct PM2.5 emissions 

differences associated with the event, 

and (2) based on the cumulative size 

distribution table in AP–42 

(Compilation of Air Pollutant Emission 

Factors), any increase in PM emissions 

associated with short-term increases in 

opacity would most likely occur in 

particle sizes larger than direct PM2.5.

Response 14. Commenter appears to 

refer to Table 1–1.6, ‘‘Cumulative 

Particle Size Distribution and SizeSpecific Emission Factors for Dry 

Bottom Boilers Burning Pulverized 

Bituminous and Subbituminous,’’ which 

is found in Chapter 1 of EPA’s AP–42, 

Compilation of Air Pollutant Emission 

Factors (http://www.epa.gov/ttn/chief/

ap42/). This table suggests that for units 

having pollutant emissions controlled 

by electrostatic precipitators (ESPs), 

PM2.5 accounts for only 29 percent of 

total PM emissions. EPA agrees the type 

of event causing an increase in opacity 

of emissions may have an effect on the 

size distribution of PM emissions. 

However, EPA disagrees that increases 

in PM emissions associated with 

increases in opacity would most likely 

occur in particle sizes larger than 2.5 

micrometers in aerodynamic equivalent 

diameter, since the circumstance that 

causes an opacity increase could occur 

while a PM control device is operating 

properly, as described by the value 

contained in the AP–42 table, or while 

a PM control device is not operating 

properly, a condition not described in 

the AP–42 table. The uncertainty 

regarding the impact of opacity 

increases on PM emissions is further 

complicated because particles 

approximately 1.0 micrometer in 

diameter have greater potential for 

increasing opacity than larger particles. 

See, e.g., Malm, William C., 

‘‘Introduction to Visibility,’’ Cooperative 

Institute for Research in the 

Atmosphere, May 1999 at Chap. 2, p. 8. 

Thus, for the increases in opacity 

contemplated in the SIP revisions at 

issue in this rulemaking, EPA is 

concerned that this increased opacity 

would probably include additional 

particles of the very types that would be 

problematic for purposes of attaining 

and maintaining the PM2.5 NAAQS. 

Comment 15. Commenters argued that 

with regard to EPA’s request for 

additional information addressing the 

relationship between opacity and PM 

emissions generally, only the 

relationship between opacity and direct 

PM2.5 would be relevant to the situation 

at hand, and that this information 

would be virtually impossible to obtain 

due to the inclusion of larger particles 

which are an inevitable part of any 

effluent gas stream. 

Response 15. EPA agrees that 

information concerning the relationship 

between opacity and PM2.5 emissions 

from a facility would be most relevant 

for purposes of evaluating impacts on 

the PM2.5 NAAQS, but EPA notes that 

no commenter provided such data, 

despite EPA’s specific request for such 

specific data. 74 FR 50934 (October 2, 

2009). EPA disagrees that this 

information would be virtually 

impossible to obtain. By way of 

example, some sources are obtaining 

and reporting these data as part of the 

current electrical utility maximum 

achievable control technology (MACT) 

rule information collection request. 

Also, under section 110(l) of the CAA, 

EPA may not approve revisions to SIP 

if the revisions would interfere with any 

applicable requirement concerning 

attainment and reasonable further 

progress (RFP), or any other applicable 

requirement of the CAA. Because there 

are also NAAQS for PM10, states and 

EPA must also consider potential 


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impacts of increases of larger particles if 

increased opacity were to include the 

emissions of larger particles from a 

source as the commenter asserted. For 

110(l) purposes, analysis of a SIP 

revision must include all of the current 

NAAQS, to the extent that the changes 

in the SIP revision could affect such 

NAAQS. With respect to this action, 

EPA has only focused on the potential 

impacts of the SIP revision on the PM2.5

NAAQS because those are the standards 

that EPA anticipates are most 

implicated by the increases in opacity at 

issue. 

Comment 16. Commenters argued that 

although an increase in opacity can be 

a good indication that PM emissions at 

the stack also are increasing, the 

magnitude of mass emissions relative to 

any one opacity value and the increase 

in mass emissions relative to increase in 

opacity generally are not quantifiable. 

Accordingly commenters asserted that 

an increase in opacity would provide no 

information regarding emission levels of 

PM2.5, as opposed to PM10 or total PM, 

and argued that any correlation between 

opacity and PM would have to be source 

specific, and even then, uncertainties 

remain. The commenters also criticized 

EPA’s information on opacity and PM, 

noting that the charts included in the 

docket do not contain sufficient 

information to evaluate the relationship 

between opacity and PM. 

Response 16. EPA agrees that an 

increase in opacity can be a good 

indication that PM emissions at the 

stack also are increasing. It is for this 

reason that we are disapproving the SIP 

revision embodied in the Submittals, 

even though the magnitude of mass 

emissions relative to any one opacity 

value and the increase in mass 

emissions relative to increase in opacity 

generally are not quantifiable. EPA also 

agrees with the commenters that a 

correlation between mass and opacity 

can be derived at a specific source, and 

EPA has in the past approved SIP 

revisions that relied on such 

correlations with sufficient technical 

analysis. 

EPA disagrees, however, that 

information about opacity increases 

provides no information regarding PM2.5

emissions specifically. Rather, 

information about opacity increases 

without concurrent PM2.5 emissions 

data or an established correlation 

between opacity and PM2.5 emissions 

cannot be expected to yield definitive 

information concerning increases in 

PM2.5 emissions. The memorandum in 

the docket, EPA–R04–OAR–2005–AL– 

0002–0064, provides the information 

known to EPA about the charts 

referenced by the commenter, EPA– 

R04–OAR–2005–AL–0002–0045 and 

EPA–R04–OAR–2005–AL–0002–0047. 

Further, the charts provided in the 

docket demonstrate the inherent 

uncertainty in the relationship between 

opacity and filterable PM mass 

emissions by showing a range of mass 

emission rates associated with a single 

opacity value and a range of opacity 

values associated with a single mass 

emissions rate. However, uncertainty 

about the precise correlation between 

mass and opacity as a general matter, 

does not mean that opacity increases 

never represent concurrent increases in 

the mass of PM emissions from a source. 

To the contrary, given the large 

increases in maximum allowable 

opacity and for the periods of time at 

issue in the SIP revision contemplated 

in the Submittals, EPA expects that it is 

likely that there could be increases in 

mass emissions. 

Comment 17. Commenter disputed 

the relationship between opacity and 

PM mass emissions based upon EPA 

statements in an unrelated rulemaking. 

The commenter asserted that despite 

providing the option for use of PM 

continuous emissions monitoring 

system (CEMS) as a compliance method 

for PM mass limits in revised NSPS 

Subparts D and Da, EPA also recently 

suggested it had concerns regarding the 

accuracy of PM CEMS measurements 

above 0.030 pounds per million British 

Thermal unit (lb/mmBtu). As a result, 

the commenter argued that EPA 

declined to exempt units operating 

above that level from the NSPS opacity 

standard even when such sources install 

PM CEMS. 74 FR 5070 (January 28, 

2009). Commenter requested, to the 

extent EPA relies on data from PM 

CEMS above 0.030 lb/mmBtu in this 

proceeding, that the Agency explain 

how it resolved those concerns. 

Response 17. EPA disagrees with the 

commenter’s conclusions regarding PM 

CEMS measurement accuracy above 

0.030 lbs/mmBtu. As mentioned in the 

cited Federal Register notice, the 

contribution of filterable PM to opacity 

at these emission levels (less than 0.030 

lb/mmBtu) is generally negligible, and 

sources with mass limits at this level or 

less will operate with little or no visible 

emissions (i.e., less than 5 percent 

opacity). As a result, EPA expects that 

an opacity standard is no longer 

necessary for such sources because the 

PM mass emission rate standard is 

substantially tighter, and the use of PM 

CEMS with continuous monitoring of 

PM emissions is more effective than 

opacity monitoring in these 

circumstances. 

This comment is also not germane to 

today’s action because the SIP revisions 

at issue did not include the requirement 

that the affected sources install PM 

CEMS as a precondition to the revision 

of the applicable opacity standard. As 

noted above, opacity standards serve an 

important role in assuring compliance 

with PM limits, for example by alerting 

regulators to problems with source 

operation or control measures that 

would not otherwise be noted except 

during a stack test for PM emissions, 

which occur only periodically. In some 

circumstances, opacity is the emission 

standard that is the subject of an 

enforcement case. 

Comment 18. A commenter 

articulated the position that its facilities 

are operating in compliance with PM 

limits in the title V permits and as a 

result, the opacity rule is not likely to 

impact PM compliance. The commenter 

further opined that ADEM should 

address any PM nonattainment issues 

separately from this rulemaking. 

Response 18. EPA disagrees with the 

assessment that opacity is unlikely to 

have any effect on PM emissions for all 

the reasons explained in this final 

action regarding that relationship. 

Further, Alabama’s visible emissions 

rule is a part of Alabama’s plan to attain 

and maintain the PM NAAQS. Even 

though it has been in the SIP for some 

time, the rule was originally included 

for that purpose. Thus there is nothing 

separate about this action and 

Alabama’s PM nonattainment issues— 

the rule at issue here is part of 

Alabama’s overall plan to address the 

PM NAAQS. Further, if a source is in 

compliance with the opacity and PM 

limits, then this disapproval action 

should have little effect on that source. 

3. Modeling 

Comment 19. Commenters argued that 

modeling is not required to demonstrate 

that changes to Alabama’s opacity rule 

will not implicate the NAAQS. 

Nonetheless, commenters argued that 

ADEM performed a modeling analysis 

demonstrating that even earlier versions 

of the SIP revision (predating the 

Submittals that EPA approved in 

October 2008) would not adversely 

affect air quality attainment or RFP 

under very conservative assumptions 

about the relationship between opacity 

and PM emissions. In addition, 

commenters argued that updated 

modeling from a consultant, ENSR (now 

known as AECOM), updated ADEM’s 

2003 modeling in 2007 using AERMOD 

(an atmospheric dispersion modeling 

system and EPA’s preferred model since 

2005) and confirmed ADEM’s earlier 

modeling results. Commenters argued 

that APC and TVA have performed 

subsequent modeling that also 


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supported the conclusion that the 

increased opacity permitted by the SIP 

revisions in the Submittals would not 

interfere with attainment and 

maintenance of the NAAQS or other 

requirement of the CAA. Commenters 

asserted that these modeling results 

show no problem with the NAAQS even 

under unrealistic, worst-case 

conditions. APC also discussed 

modeling done at APC Plants Barry and 

Greene and TVA Plant Colbert which 

APC believes supports affirming EPA’s 

2008 final action approving the 

Alabama SIP revisions. Commenters 

further noted that ADEM performed a 

modeling analysis demonstrating that 

the SIP revisions would not affect air 

quality attainment under very 

conservative assumptions about a 

relationship between opacity and PM 

emissions. According to the 

commenters, modeling performed by 

TVA confirms that particulate emissions 

from the Colbert facility would not 

interfere with maintenance of the PM10

or PM2.5 NAAQS, even for the 

unrealistic scenario in which the ESPs 

are shut down for 10 percent of the time 

every day of the year. 

Response 19. EPA disagrees with the 

commenter’s assertions. As discussed in 

73 FR 60961 (October 15, 2008), all 

modeling results are predicated on a 

known or assumed correlation between 

opacity and PM mass emissions. 

Because this correlation can differ for 

each source and operating condition, 

modeling that does not use sourcespecific correlations does not and 

cannot demonstrate with certainty the 

impact of changes in opacity on PM 

NAAQS. With respect to the modeling 

described by the commenters, the 

models do not demonstrate that the 

Submittals would not interfere with 

attainment or maintenance of the 

NAAQS because the models do not 

appear to have included condensable 

PM or background analyses, to have 

assessed the impact of nearby PM 

emissions sources, or to have assessed 

the impact of secondary PM formation. 

Generally, however, the utility of 

modeling would still be limited because 

the precise relationship between opacity 

levels and PM mass emissions is not 

known. The docket for this action 

includes a technical support document 

(TSD) summarizing the modeling that 

EPA received and some of the key 

assumptions and other issues that 

impacted the utility of the modeling. 

Comment 20. Commenters argued that 

EPA has routinely approved SIP 

demonstrations based on the use of air 

models, rightly concluding in such 

matters that the use of the air models 

leads to a reasonable demonstration of 

compliance with the NAAQS. 

Response 20. As a general matter, EPA 

agrees that modeling can be a useful tool 

in appropriate circumstances. In this 

case, the modeling provided did not 

reduce uncertainty regarding the 

relationship between opacity and PM 

emissions sufficiently to support 

approval of the Submittals. Further, the 

modeling did not conclusively 

demonstrate that there would be no 

impact on the NAAQS. Thus, EPA could 

not conclude that the modeling 

submitted supported approval of the 

Submittals under section 110(l). EPA’s 

modeling TSD provides more 

information on the modeling submitted 

to EPA as part of this action. 

Comment 21. Commenters stated that 

monitoring data show a decline in 

ambient PM2.5 and PM10 levels at 

monitors that could potentially be 

impacted by TVA’s Colbert and Widows 

Creek Plants. 

Response 21. EPA acknowledges that 

ambient PM levels have been improving 

in many parts of the country as a result 

of rigorous state and EPA efforts to 

control emissions from many sources of 

various types. EPA wants to maintain 

these improvements and to support 

further improvements for protection of 

public health as many areas are still 

designated nonattainment for the 

NAAQS. Indeed, this is among the 

reasons why reviewing SIP revisions 

pursuant to section 110(l) is such an 

important exercise. 

4. Relative Stringency of Previous Rule 

(Pre-2008 Final Action) to Current Rule 

(Post 2008 Final Action) 

Comment 22. Commenters argued that 

Petitioners’ claims regarding ‘‘bundling’’ 

or other potential ways of ‘‘using’’ 

Alabama’s visible emissions revisions to 

somehow reduce control efforts while 

still meeting permit requirements are 

misplaced. According to the 

commenters, it is extremely difficult to 

achieve continuous or near-continuous 

compliance with the opacity rules, so 

there is absolutely no incentive to try to 

‘‘game’’ the system by trying to achieve 

less than maximum opacity control at 

any one time. Further, commenters 

argued that facility procedures aimed at 

minimizing opacity levels at all times in 

order to avoid non-exempted 

exceedances insofar as practicable 

remain intact after the rule revisions 

went into effect January 1, 2009. 

Response 22. The commenters’ 

argument appears to be that even though 

‘‘bundling’’ could occur, it will not, 

because sources are diligently striving to 

minimize their opacity levels. While 

EPA certainly expects that sources are 

seeking to minimize their opacity levels, 

EPA’s analysis of the revision 

considered what the two versions of the 

Alabama rules allowed—and not 

necessarily how sources were operating 

under each rule scenario. As with the 

modeling submitted by many 

commenters, the primary problem 

associated with their conclusions about 

the amount of PM emissions during 

longer periods of elevated opacity is the 

reliance on an assumed relationship 

between opacity and PM emissions that 

has not been established for the specific 

source. As mentioned previously, this 

relationship is unknown for each source 

and operating condition, absent 

sufficient evaluation. EPA disagrees that 

the ‘‘bundling’’ of periods of high 

opacity could never reflect higher PM 

mass emissions. 

EPA understands the difficulties 

associated with operating older 

facilities, but disagrees that continuous 

compliance with opacity rules can be 

achieved only through extreme 

difficulty. The Alabama SIP opacity 

limits in effect following this 

disapproval should generally be capable 

of being met by a source that is properly 

maintained, operated and controlled. 

There are control technologies and 

operational paradigms that allow older 

facilities to comply with Alabama’s preOctober 15, 2008, opacity rules (this was 

recognized by the court in the TVA 

Colbert case, Sierra Club v. TVA, 592 F. 

Supp. 2d 1357 (N.D. Ala. 2009)). 

Comment 23. Commenter explained 

that to attempt to bundle six-minute 

opacity exceedances would necessitate a 

purposeful ‘‘turn-down’’ of the unit’s 

ESP and, thus, result in non-compliance 

with two provisions of the commenter’s 

Lowman Plant’s major source operating 

permit (title V permit): (1) That ‘‘all air 

pollution control devices * * * be 

* * * operated at all times in a manner 

so as to minimize the emissions of air 

contaminants,’’ and (2) once the 

emissions exceed a six-minute average 

opacity of 20 percent, corrective actions 

must be taken within two hours. 

Response 23. EPA’s analysis of the 

SIP revisions at issue is governed by, 

among other provisions, section 110(l) 

of the CAA. In that context, as was 

explained previously, EPA must 

compare the existing SIP and the 

proposed SIP revision. While affected 

sources may have permit limits that are 

more stringent than the applicable SIP 

regulations, EPA’s analysis must focus 

on what the SIP itself would allow. 

Permits may be revised from time to 

time, depending on applicable 

requirements. As a result, the type of 

analysis completed by the commenter 

based on the applicable permits might 


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20The SIP revisions at issue have been under 

reconsideration since before the changes to 

Alabama’s visible emissions rule now being 

disapproved went into effect; thus, the data 

submitted in public comments may not be a 

representative random sampling of the long-term 

effects of the rule. 

be changed over time. Further, while 

EPA would, of course, be concerned by 

a purposeful ‘‘turn-down’’ of any control 

device, EPA expects that there are other 

circumstances under which extended 

periods of consecutive exemptions 

would allow high opacity levels (and 

mass emissions) that would not occur in 

a well-operated, well-controlled, and 

well-maintained plant. EPA appreciates 

PowerSouth Energy Cooperative’s 

(PSEC’s) analysis, which demonstrates 

that this disapproval action should have 

little effect on the vast majority of 

sources. 

Comment 24. Commenters provided 

data in three attachments provided by 

PSEC showing emissions during the 

period of January 1, 2009, thru 

September 30, 2009, clearly indicate 

that no ‘‘bundling’’ occurred. For 

example, Attachment 1 shows that of 

the total of 90 six-minute periods of 

excess opacity (i.e., six-minute averages 

of opacity greater than 20 percent), 

including startup/shutdown and load 

change periods, there were 40 

occurrences of isolated six-minute 

periods of excess opacity; 14 

occurrences of two consecutive sixminute periods of excess opacity; four 

occurrences of three consecutive sixminute periods of excess opacity; one 

occurrence of four consecutive sixminute periods of excess opacity; and 

one occurrence of six consecutive sixminute periods of excess opacity. 

Response 24. EPA appreciates the 

submission of operating data. One of the 

difficulties with the technical analysis 

regarding opacity is that details 

regarding facility operation can impact 

both opacity and PM in different ways. 

Further, EPA must consider the effect of 

the Submittals on how a facility may be 

allowed to operate, not just how the 

facility actually has been operating. 

With these considerations in mind, the 

operating data were informative, but not 

determinative, because even if a facility 

currently operates as the commenters 

describe, the facility would be allowed 

to operate otherwise under Alabama’s 

proposed SIP revisions. 

Comment 25. Commenters suggested 

that this 22 percent limit ensures that 

the average daily opacity under the 

revised SIP is no greater than under the 

previous SIP. The commenters asserted 

that this fully responds to AEC’s 

hypothesis of the ‘‘bundling of high 

opacity periods’’ and concerns about the 

elimination of the ‘‘40 percent cap’’ 

under the revised SIP. Further the 

commenters explained the use of a daily 

opacity limit to establish short-term 

equivalency is appropriate because a 

calendar day is the shortest period over 

which compliance with the PM NAAQS 

is measured. The commenters stated 

that AEC provides no supporting data 

on the bundling and operating data 

provided, which commenters believe 

demonstrates that bundling has not 

occurred. 

Response 25. The Commenters’ 

statements are incomplete. While the 22 

percent limit does serve the purpose of 

ensuring subject sources are constrained 

by the same maximum allowable 

average daily opacity as under the 

previously approved SIP (as explained 

in EPA’s 2008 final notice), these SIP 

revisions would allow opacity levels of 

up to 100 percent during exempt 

periods and for multiple consecutive 

exempt periods, neither of which was 

previously authorized under the SIP. 

The prior version of the visible 

emissions rule capped maximum 

opacity at 40 percent and limited the 

time at such level to only six minutes 

per hour. Further, whether ‘‘bundling’’ 

in fact has occurred in the past is not 

the focus of EPA’s analysis for purposes 

of section 110(l).20 As part of this 

reconsideration, EPA has had to reevaluate the concept of the ‘‘22 percent 

daily cap’’ supported by the commenter. 

EPA has concluded that even with an 

‘‘average daily opacity’’ cap, these SIP 

revisions undermine the purpose and 

effectiveness of the opacity standard by 

allowing extended periods of high 

opacity. Such high opacity can be 

indicative of problems with control 

device operation or other circumstances 

potentially leading to increased mass 

emissions. Given that some sources 

affected by the opacity limits at issue in 

the SIP revisions are located within 

designated nonattainment areas, EPA 

concludes that this likelihood of 

increased emissions renders the 

Submittals unapprovable under section 

110(l). 

Comment 26. Commenters argued that 

the equivalency between the previous 

and revised SIPs, with respect to the 

short-term and long-term emission rates, 

will ensure that there will be no 

interference with NAAQS 

notwithstanding the bundling of high 

opacity periods. Further, the 

commenters mentioned that in 

approving the North Carolina SIP 

revision for visible emissions, EPA 

concluded that such bundling through 

the ‘‘elimination of the current 

restriction of no more than one six 

minute exception period per hour’’ does 

not ‘‘pose a problem for purposes of 

Section 110(l).’’ Commenters cite to 70 

FR at 61558 for support. 

Response 26. As EPA explained 

earlier in this final action, the North 

Carolina opacity revisions are not 

analogous to Alabama’s opacity 

revisions for the main reason that 

Alabama’s revisions allow for periods of 

opacity up to 100 percent, whereas the 

North Carolina revision retained the 

same maximum opacity of 40 percent. 

The allowance for this high opacity 

level, along with the lengthy time 

allowed for elevated opacity (up to 2.4 

consecutive hours), was not present in 

the North Carolina case. 

Comment 27. Commenters argued that 

plant operating data confirm that the 

bundling of high opacity periods does 

not occur in practice. Further, the 22 

percent cap resolves any concerns 

regarding the bundling were it to occur. 

Response 27. EPA appreciates 

commenters’ information on actual 

operations; however, as explained 

previously EPA’s analysis under section 

110(l) focuses on what the revised SIP 

rules would allow. Further, as discussed 

above, the 22 percent cap does not 

resolve EPA’s concerns about extended 

periods of very high opacity. 

Comment 28. Commenters argued that 

the rule really has nothing to do with air 

quality, and that if it did, EPA would 

have to justify and explain why it is 

proposing to condemn an opacity rule 

that is numerically more stringent and 

that has fewer exemptions than many 

other states’ opacity rules. 

Response 28. EPA does not agree with 

commenters’ statements. Alabama’s 

visible emissions rule is part of 

Alabama’s EPA-approved SIP, and part 

of its plan to attain and maintain the PM 

NAAQS. As a result, any revision of the 

EPA-approved opacity rules is subject to 

evaluation under section 110(l) of the 

CAA. Furthermore, the extended 

consecutive periods of opacity 

exemptions allowed renders this 

standard uniquely less stringent than 

any other EPA-approved opacity rule. 

Comment 29. Commenters argued that 

the daily opacity limit is neither 

necessary for approval nor unlawful. 

According to the commenters, because 

EPA’s proposed approval was not based 

on a finding that the rule would not 

allow any more PM during a 24-hour 

period than the old rule, it is not 

necessary for the daily limit to meet 

such a criterion. 

Response 29. EPA disagrees that the 

potential for more PM emissions as a 

result of elevated opacity is not germane 

to this action. EPA’s prior approval of 

the SIP revisions was based on 

uncertainty about whether the revisions 


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to the opacity standard would allow 

more PM emissions during a 24-hour 

period. EPA would not have previously 

proposed approval if the record clearly 

demonstrated that the rule would have 

resulted in increased PM in 

nonattainment areas. After reviewing 

public comment and the State’s revised 

submissions, EPA based its prior 

approval in part on the average daily 

opacity limit included in the revision. 

At that time, EPA accepted certain 

assumptions, including that the 22 

percent daily opacity limit would serve 

to lessen the potential for elevated 

emissions of PM associated with the 

increases in opacity. Following EPA’s 

reconsideration and review of 

information submitted to EPA, EPA no 

longer accepts that the average daily 

opacity limit is an appropriate or 

effective tool for evaluating the impact 

of the Submittals on PM emissions. 

Given EPA’s position that there is a 

sufficient likelihood of increased PM 

emissions associated with the elevated 

opacity allowed under the SIP revisions, 

the Submittals are not approvable under 

110(l). 

5. Attainment and Maintenance of the 

PM NAAQS (PM10 and PM2.5) and Data 

Submitted in Response to October 2009 

Reconsideration Proposal 

Comment 30. Commenter argued that 

while the Clean Air Fine Particle 

Implementation Rule requires that 

direct PM2.5 emissions be addressed in 

PM2.5 attainment demonstration SIPs, 

the primary thrust of the regulation is 

the control of precursor compounds and 

not direct PM2.5 emissions. According to 

the commenters, if the Alabama 

attainment plans are similar to those of 

Tennessee in that sulfates are identified 

as the main contributor to fine 

particulate matter and reliance is being 

placed on reductions of sulfur dioxide 

(SO2) to demonstrate compliance, with 

no measure specified for stationary 

direct PM2.5, then the Petitioners’ 

assertion that approval of the Alabama 

SIP revisions would adversely affect 

PM2.5 attainment or RFP has no merit 

and should be rejected. The commenters 

explained that if this is the case then the 

Petitioner’s assertion that approval of 

the Alabama SIP revisions would not be 

consistent with sections 110(l) and 193 

of the CAA should also be rejected as 

having no merit unless it can be 

demonstrated that a fixed source of 

direct PM2.5 is a significant contributor 

to a nonattainment area. Additionally, 

according to the commenters, this 

should be an adequate affirmative 

demonstration that the requirements of 

sections 110(l) and 193 of the Act are 

not an issue. Further, the commenters 

asserted that even for areas achieving 

conformance with the PM2.5 ambient 

standard, for which no SIP would be 

required, the effect of the reductions of 

PM2.5 precursors would be so dominant 

as to negate any changes to direct PM2.5

emissions. 

Response 30. As was explained 

earlier, given that ADEM did not submit 

a full attainment demonstration 

specifically addressing this rule and did 

not propose any offsetting reductions to 

compensate for emission increases in 

nonattainment areas, EPA’s analysis is 

necessarily focused on the comparison 

between the previous EPA-approved 

version of the visible emissions rules 

and the revisions that the State seeks, in 

order to ensure that the revision would 

not allow an increase in emissions of 

pollutants that would interfere with 

attainment or maintenance of the 

NAAQS, or with other requirements of 

the CAA. A primary consideration, 

therefore, is whether the revisions could 

result in increases in emissions of a type 

for which the area where the source is 

located is designated nonattainment. In 

this context, EPA must evaluate the 

relative stringencies of the two versions 

of the opacity rules, as was explained 

earlier. 

EPA notes that the commenter’s 

arguments here are premised upon what 

might or might not be appropriate in the 

context of a nonattainment SIP for 

certain pollutants in an area. EPA does 

not agree that the implementation 

regulations for the 1997 PM2.5 NAAQS 

are designed or intended to ignore direct 

PM2.5 emissions from sources, and 

evaluation of controls for such 

emissions is a required element of such 

a SIP. While it may be correct that a 

nonattainment SIP in a particular area 

might be designed to focus upon 

emissions of SO2 and nitrogen oxides, or 

other PM2.5 precursors, as an attainment 

strategy, it does not follow that 

emissions of PM2.5 from the sources 

subject to Alabama opacity rule do not 

impact attainment and maintenance of 

these NAAQS. Considerations 

mentioned by the commenters might be 

relevant in the evaluation of the 

attainment demonstration 

accompanying a nonattainment SIP for 

the 1997 PM2.5 NAAQS, but they are not 

relevant in the context of a section 

110(l) analysis. 

Comment 31. Commenters argued that 

Alabama’s revised SIP for visible 

emissions is a small piece in the overall 

PM attainment puzzle. According to the 

commenter, any incremental primary 

PM2.5 emissions increase as a result of 

revising the SIP, assuming for purposes 

of argument that such an increase 

occurs, would be an inconsequential 

contributor to the PM2.5 attainment 

status against the background of the 

significantly greater secondary PM2.5

(sulfate and nitrate) contributions. The 

commenter asserted that viewed in this 

broader context, EPA could reasonably 

conclude, based on the equivalency 

demonstration, that the revised SIP is 

consistent with the earlier SIP. 

Response 31. The comment fails to 

appreciate EPA’s limitations in 

reviewing SIP revisions, as described in 

section 110(l). In addition, EPA did not 

receive an ‘‘equivalency demonstration’’ 

from ADEM that addressed all the 

elements in section 110(l). Further, an 

increase of PM emissions by any 

increment would make it more difficult 

for areas in Alabama to attain and 

maintain the NAAQS. EPA has 

considered the SIP as a whole, and 

concludes that the potential increase 

renders the revisions not approvable. 

Comment 32. Commenters explained 

that following new data collected under 

the current SIP confirms that EPA’s 

prior analysis was sound: 

A. New data collected under the 

current SIP shows there is no 

‘‘bundling;’’ 

B. New data collected under the 

current SIP shows that daily opacity has 

improved; and 

C. New data collected under the 

current SIP shows why the rule makes 

sense. 

Response 32. EPA appreciates the 

submission of these data. EPA disagrees, 

however, with the conclusions that the 

commenters draw from the data. The 

commenters’ focus on what is actually 

happening with respect to ‘‘bundling’’ 

and opacity levels fails to consider what 

could happen under the SIP revision. 

EPA’s analysis pursuant to section 

110(l) must focus on the differences 

between the two versions of the visible 

emissions rules in terms of what they 

would allow and not on the choices 

individual facilities may have made to 

date in terms of opacity and PM 

emissions. Thus, EPA does not agree 

that the data presented by commenters 

support approval of the Submittals. The 

commenters did not, unfortunately, 

submit data to establish what the PM 

mass emissions were during periods of 

elevated opacity at these sources. 

Comment 33. Commenter saw no 

basis for the supposition that Alabama’s 

opacity rule revisions will affect PM 

NAAQS compliance. The commenters 

asserted that as indicated in the 

attachments, PSEC’s Lowman Unit 1’s 

opacity compliance continues to be very 

good. Additionally, the commenters 

explained that annual particulate 

emission testing in 2008 and 2009 

indicate PM emissions well below the 


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standard and show no difference before 

and after the opacity rule revisions. 

Response 33. EPA acknowledges that 

some facilities affected by the SIP 

revisions may be operating at opacity 

levels below those required by the 

Alabama SIP. Indeed, a source that is 

well-controlled, well-maintained, and 

well-operated could achieve opacity 

levels well below 20 percent. However, 

EPA’s obligation under section 110(l) is 

to consider how a facility could operate 

under the new rule—not how it 

typically operates or has historically 

operated. Moreover, EPA notes that 

annual PM testing offers valuable but 

limited information about mass 

emissions because the testing occurs 

only once per year for a limited period 

of time. The question not addressed by 

the comments is what the PM mass 

emissions would be, were a source to be 

operating at the 100 percent opacity for 

2.4 hours contemplated by the SIP 

revision at issue. 

Comment 34. Commenters asserted 

that there are no new data that would 

support EPA’s withdrawal of its 

approval of the rule. 

Response 34. As was discussed 

previously, EPA’s authority to 

reconsider a SIP revision is not limited 

only to circumstances where there are 

new data. EPA has already explained in 

today’s action why its prior approval 

was not consistent with the purposes of 

section 110(l), and that reconsideration 

and disapproval is appropriate. Notably, 

the reconsideration was initiated before 

the revised rule went into effect and that 

sources should be capable of complying 

with either rule or both rules 

simultaneously. 

In addition, EPA disagrees that no 

new information supports this 

disapproval. A number of commenters 

have submitted data and information 

that, while not directly addressing the 

questions that EPA posed, nevertheless 

help to illustrate the problems with the 

SIP revisions. For example, information 

submitted by AEC suggests that at least 

some sources, under some conditions, 

could have increased PM emissions 

during the longer periods of higher 

opacity that would be permissible under 

the revised visible emissions rules in 

the Submittals. See Comment Letter 

from George E. Hays and attachments 

(on behalf of Alabama Environmental 

Council, among others), Docket No. 

EPA–R04–OAR–2005–AL–0002–0089.1. 

Moreover, many of the commenters 

during the reconsideration process 

submitted comments in which their 

analysis suggested that there is a 

relationship between PM mass 

emissions and opacity, even if the 

precise correlation cannot be 

established without much more rigorous 

testing and evaluations on a source 

specific basis. See Modeling TSD. As 

was noted earlier, even some of the 

commenters opposing EPA’s 

disapproval action identified the 

uncertainty in the relationship between 

opacity and PM mass emissions, and the 

possibility of the SIP revisions resulting 

in emission increases. See, e.g., 

Comment Letter from Lauren E. 

Freeman (on behalf of the Utility Air 

Regulatory Group) at 4, Docket No. 

EPA–R04–OAR–2005–AL–0002–0086.1. 

Comment 35. Commenter noted that 

with regard to EPA’s request for 

information on condensable PM, COMS 

do not measure condensable PM, which 

is in a gaseous form at stack conditions. 

Response 35. EPA acknowledges the 

response, which underscores one 

component of the uncertainty inherent 

in the relationship between opacity and 

PM emissions. 

6. Impact of Uncertainty in These SIP 

Revisions 

Comment 36. Commenters asserted 

that while EPA has consistently (and 

correctly) noted the uncertain 

relationship between opacity and PM 

for short-term analysis, any question 

regarding how this uncertainty might 

impact PM, in this case, has now been 

eliminated entirely with the addition of 

the 22 percent daily average 

requirement. Commenters further stated 

that ADEM’s August 2008 submittal 

remedied any ‘‘uncertainty’’ question 

with respect to 24-hour PM by including 

an additional restriction on daily 

average opacity, so that the average 

daily opacity allowed under the revision 

is now no greater than under the 

previous SIP. 

Response 36. EPA has shown through 

calculations, that the maximum 

allowable average daily opacity under 

both the previous rule and the revised 

rule is 22 percent. However, as 

discussed above, the revised visible 

emissions rule at issue in the SIP 

revisions would allow sources to 

operate in a manner they could not 

under the previous rule—including 

increases in opacity concentrations up 

to 100 percent for an extended period of 

time. As a result, under the revised rule, 

sources may now be permitted to cause 

much more opacity to levels that would 

have been a violation under the 

previous EPA-approved SIP rules. Such 

emissions include very high 

concentrations of excess opacity for 

extended periods. EPA has thus 

concluded that the ‘‘average daily 

opacity’’ cap provides no assurance 

against increased mass emissions. 

Indeed, as discussed above, EPA has 

concluded that there is a sufficient 

likelihood of increased mass emissions 

under the revisions so as to make it 

unapprovable under section 110(l). 

Comment 37. Commenters stated that 

there is always some uncertainty when 

attainment or interference with a 

NAAQS is considered in a SIP process 

because it involves an element of 

prediction and reliance on modeling. 

Further, commenters explain their 

positions that section 110(l) does not 

require absolute certainty and EPA 

should not substitute ‘‘could’’ for 

‘‘would’’ in the 110(l) context. 

Response 37. EPA agrees the Act does 

not require attainment demonstrations 

or other technical analysis of impacts on 

attainment or maintenance of the 

NAAQS to an ‘‘absolute certainty.’’ 

However, to make a determination that 

the NAAQS will not be adversely 

impacted, EPA must at least be able to 

reach the conclusion that this is most 

likely the case. In this action, EPA is 

relying on what is known about the 

relationship between opacity and PM 

emissions to conclude that the State’s 

revised visible emissions rules in the 

Submittals is less stringent than the 

previous EPA-approved rule, and that 

the likely increases in emissions of PM 

at affected sources would be 

inconsistent with section 110(l). Under 

the revised rule, a source could exceed 

its 20 percent opacity limit for well over 

an hour (up to 100 percent opacity). In 

contrast, the previous SIP-approved rule 

allowed only one occurrence per hour of 

a 6-minute average opacity above 20 

percent (and only up to 40 percent). 

Control equipment that is effective 

enough to avoid a second occurrence of 

6-minute average opacity above 20 

percent will make even the first 

occurrence an infrequent event. 

Likewise, control equipment and 

operating procedures that are effective 

enough to enable a unit to meet the 

requirements of the previous SIP will 

also allow a lesser quantity of PM 

emissions than control equipment and 

operating procedures that are sufficient 

to comply with the current SIP revision 

but do not necessarily enable a unit to 

comply with the previous SIP rule. 

In addition, contrary to the 

commenters’ belief, this is not 

dependent upon replacing the word 

‘‘would’’ with the word ‘‘could.’’ EPA’s 

conclusion is that available evidence 

indicates that some of the affected 

sources would have increases in PM 

emissions, and that these emissions 

would occur in locations where such 

increased emissions would interfere 

with attainment and maintenance of the 

NAAQS. Commenters evidently 

misconstrue ‘‘uncertainty’’ about the 


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precise amount of such likely emissions 

increases as evidence that no such 

increases could occur. 

Comment 38. Commenters raised 

concerns regarding PM CEMS 

technology, and the representativeness 

of PM emissions data obtained during 

Performance Specification (PS) 11 

testing. See 40 CFR part 60, Appx. B. 

Briefly, the commenters asserted that PS 

11 correlation testing, which requires 

disabling of PM control devices under 

artificial conditions in order to obtain 

sufficient variability in PM emissions to 

satisfy the PS 11 statistical criteria, 

rarely provide data representative of 

actual operations or control device 

malfunctions. Commenters also noted 

that it would not make sense to require 

sources to spend money to install PM 

CEMS or to perform periodic 

performance tests in order to develop a 

source-specific correlation between 

opacity and PM. 

Response 38. EPA disagrees with the 

commenter’s views regarding PM CEMS 

technology and PS 11 testing, especially 

in the context of evaluating the SIP 

revisions at issue here. The procedures 

of PS 11 are conducted to develop a 

source-specific PM emissions 

correlation for an individual source 

operating over a range of PM emissions 

conditions through comparison of 

results from PM emissions testing and 

PM CEMS. Note that PS–11 does not 

require PM control devices to be 

disabled. Those PM measurement and 

testing correlation procedures differ 

from an opacity and PM emissions 

correlation, which is the fundamental 

issue requiring resolution for addressing 

the visible emissions rules revision in 

Alabama’s Submittals. EPA also 

disagrees that use of PM CEMS or 

periodic performance testing could be 

‘‘nonsensical’’ in determining a sourcespecific correlation between opacity and 

PM emissions. Indeed, as EPA has 

previously explained, source-specific 

approaches such as concurrent opacity 

and PM emissions measurements may 

be one way to determine ‘‘* * * any 

useful and definitive relationships 

between stack particulate mass 

emissions values and their 

corresponding opacity levels * * *’’ 73 

FR 60962 (October 15, 2008). 

EPA agrees that data obtained over a 

range of operating and control device 

conditions would be necessary to 

develop a site-specific correlation 

between opacity and PM emissions and 

that a single, site-specific correlation 

should not be extrapolated to other 

sources. Retaining Alabama’s original 

visible emissions rule (the pre-October 

15, 2008, final rule) relieves ADEM (and 

affected sources) from performing an 

assessment of increased source opacity 

on PM emissions. 

Comment 39. Commenters suggested 

that the source-specific nature of the 

opacity/PM relationship does not mean 

that the uncertain impact of a particular 

change in an opacity rule can be 

resolved by requiring source-specific 

testing. 

Response 39. EPA agrees that a welldesigned data collection program 

should be able to reduce to acceptable 

levels, if not eliminate, most of the 

uncertainty associated with the 

relationship between PM emissions and 

opacity resulting from changing opacity 

limits. However, as the commenters 

themselves argue, the variability in the 

relationship between PM emissions and 

opacity limits is such that, absent the 

use of PM CEMS, source specific 

evaluation would be one way to 

determine the impacts of the change at 

a given source. EPA through this 

disapproval is not determining that the 

only means to revise an opacity 

standard is through source by source 

evaluation, nor is EPA requiring that 

with today’s action. 

Comment 40. Commenters argued that 

to the extent that EPA seeks information 

on PM compliance methods in order to 

assess the costs of requiring Alabama to 

impose more source-specific PM testing 

in order to evaluate the impact of its 

revised opacity rule, commenters 

disagree that such an evaluation is 

required under CAA 110(l). 

Response 40. EPA agrees that an 

assessment of the cost of a potential 

requirement for source-specific testing 

is not necessary pursuant to section 

110(l). In order to fully provide the 

public with an opportunity to comment 

on the proposed action, EPA sought 

specific information, including costs, to 

assist the public in identifying what 

information might be useful to EPA. 

EPA has already explained how it 

considered the SIP revisions and the 

basis for its final action. 

7. Applicability of CAA Sections 110(l) 

and 193 to This Action 

Comment 41. Commenters stated that 

because EPA correctly found the 

revisions would not interfere with the 

attainment or maintenance of the 

NAAQS or any other requirement of the 

CAA, section 110(l) concerns are not 

implicated. The commenters stated that 

as long as a SIP revision does not 

‘‘interfere with’’ air quality (i.e., make it 

worse), EPA must approve it. According 

to the commenter, Alabama’s rule is 

consistent with the development of an 

overall plan for attainment, in that all of 

the sources subject to the Rule are also 

subject to various other programs and 

requirements that EPA has approved to 

ensure the NAAQS are protected. 

Response 41. Commenters’ focus on 

‘‘air quality’’ is a good point—and was 

EPA’s primary concern as well. EPA’s 

action in this case focuses on the known 

differences between the previous EPAapproved SIP rules and the SIP 

revisions in the Submittals, and what is 

known regarding the technical aspects 

of the relationship between opacity and 

PM mass emissions. Specifically, that 

the revised rule allows extended periods 

of much higher opacity that were not 

previously authorized. EPA has 

concluded that available evidence 

indicates that the revised rule could 

result in more emissions, and thus 

interfere with attainment and 

maintenance of the NAAQS, to use the 

commenters’ term, ‘‘make it worse.’’ 

Further, for older facilities (such as the 

ones subject to the visible emissions 

rule at issue), particularly those that are 

less controlled, opacity can be an 

important indicator of operation and 

control device performance, which, in 

turn, can affect air quality. In this 

context, and lacking reliable scientific 

correlations between opacity emissions 

and PM NAAQS violations, EPA has 

concluded that the rule changes 

described in the Submittals are not 

approvable under section 110(l). 

With respect to the commenters’ 

argument that other regulatory programs 

exist to help insure attainment and 

maintenance of the NAAQS, EPA 

agrees. However, for the sources affected 

by the visible emissions rules at issue, 

the opacity standards provide an 

important tool to assure compliance 

with these other measures. The mere 

existence of a regulatory framework to 

provide for the attainment of the 

NAAQS does not negate the need for 

effective tools to assure that the 

framework succeeds. 

Comment 42. Commenters stated that 

unless ADEM relied upon the opacity 

standard to comply with the PM 

NAAQS, section 110(l) considerations 

do not come into play. The commenters 

further stated that in this case, Alabama 

did not rely on the opacity standard to 

demonstrate attainment of the PM 

NAAQS. 

Response 42. Alabama’s visible 

emissions rule is part of Alabama’s plan 

to attain and maintain the NAAQS, and 

it is in the EPA-approved SIP (and has 

been for a long time). Any revision to 

the SIP is subject, by the plain text of 

the CAA, to the requirements of section 

110(l). 

Comment 43. Commenters stated that 

EPA’s October 2008 approval applied 

and satisfied the correct CAA section 

110(l) standard. According to the 


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21As was discussed above, EPA also concludes 

that even if the uncertainty about the impact of the 

SIP revision on PM emissions were so great that 

EPA could make no technical judgment at all about 

the net effect of this SIP revision on PM emissions, 

the revision would still not be approvable under 

section 110(l). 

commenters, EPA is not required to reexamine the adequacy of the level of 

reductions provided in a plan that has 

already achieved attainment, or 

speculate how a requested SIP revision 

might fit into the mix of controls that 

may be chosen by the state to support 

a future attainment demonstration with 

respect to a new standard. The 

commenters argued that EPA’s review 

under CAA section 110(l) only needs to 

address whether the revision would 

affect the status quo. EPA could have 

(and in commenters’ view, should have) 

limited its review to whether the 

revision interfered with the requirement 

to assess good O & M of PM control 

equipment between PM stack tests. 

Further the commenters asserted that 

because Alabama did not rely on a 

short-term opacity/PM relationship to 

support its previously approved PM 

attainment demonstration, EPA was not 

required to analyze changes in the 

opacity standard for equivalency under 

section 110(l). 

Response 43. EPA does not agree with 

commenters’ characterization of EPA’s 

obligation under section 110(l). As a 

point of clarification, Alabama has 

several nonattainment areas, including 

PM2.5 nonattainment areas. The State’s 

visible emissions rule applies to a group 

of stationary sources Statewide—it does 

not apply only in designated attainment 

areas. Thus, EPA does not agree with 

commenters’ argument that because 

Alabama is currently attaining some 

NAAQS, EPA’s consideration under 

section 110(l) should be different. 

Further, as was noted earlier, in the 

absence of an attainment demonstration 

regarding the rules at issue, EPA can 

approve a SIP revision for a 

nonattainment area only if EPA finds 

that it will not worsen air quality by 

increasing emissions of a nonattainment 

pollutant, and it is otherwise consistent 

with attainment and maintenance of the 

NAAQS. Even accepting the 

commenters’ argument that the opacity 

standard is intended to be a gauge of 

good O & M of a source, the SIP 

revisions contemplated in the 

Submittals raise concerns because the 

revisions allow facilities to emit up to 

100 percent opacity for extended 

periods of time—which is hard to 

square with the need to assure good 

source operation. Indeed, other 

commenters have asserted that opacity 

at such levels is the equivalent to 

turning off any relevant control device 

for an extended period of time. Even 

under what EPA understands 

commenters’ argument to be, the SIP 

revisions present serious concerns about 

good O & M and would not be 

approvable. 

Comment 44. Commenters explained 

their view that 110(l) does not impose 

on states a requirement to ‘‘demonstrate’’ 

that each proposed revision will not 

interfere with attainment or require EPA 

to reject each revision that presents 

‘‘some remote possibility for 

interference.’’ Commenters cited to 

Kentucky Resources Council (KRC), Inc. 

v. EPA, 467 F.3d 986, 994–95 (6th Cir. 

2006) for support. 

Response 44. Section 110(l) prohibits 

any SIP revision that would have the 

effect of interfering with attainment or 

maintenance of the NAAQS, RFP, or any 

other requirements of the CAA. 

Typically, states elect to provide the 

requisite information necessary to 

establish that their intended SIP 

revisions would not have any of these 

effects. EPA often works with states to 

evaluate the effects of a given SIP 

revision. In the final analysis, however, 

EPA is not authorized to approve any 

SIP revision that has such effects. 

When, as here, available information 

indicates that the SIP revision at issue 

could result in the increase in PM 

emissions at some sources located in or 

near designated PM nonattainment 

areas, EPA has concluded that the SIP 

revision is not approvable and that 

residual uncertainty about the precise 

amount of additional PM emissions that 

would be associated with the dramatic 

increases in opacity does not render the 

revision approvable. 

Commenters’ citation to KRC, 467 

F.3d 986, is misplaced because the case 

supports EPA’s disapproval action. In 

that case, the Sixth Circuit considered 

an EPA action approving revisions to 

the Kentucky SIP regarding Kentucky’s 

inspection and maintenance (I/M) 

program that removed the requirement 

from the active portion of Kentucky’s 

SIP. The Court explained that Congress 

did not intend for EPA to ‘‘reject each 

and every SIP revision that presents 

some remote possibility for interference. 

Thus, where the EPA does not find that 

a SIP revision would interfere with 

attainment, approval of the revision 

does not do violence to the statute.’’ KRC 

at 994. The Court upheld EPA’s view 

that: 

As long as actual emissions in the air are 

not increased, EPA believes that equivalent 

(or greater) emissions reductions will be 

acceptable to demonstrate non-interference. 

EPA does not believe that areas must wait to 

produce a complete attainment 

demonstration to make any revisions to the 

SIP, provided the status quo air quality is 

preserved. 

KRC at 995 (quoting a prior SIP action, 

70 FR 28,429, 28,430 (May 18, 2005)). 

During the course of the SIP revision at 

issue in that case, EPA informed 

Kentucky of the need to demonstrate 

equivalent offsetting reductions due to 

the existing nonattainment areas in 

Kentucky. Kentucky responded by 

adopting additional control 

requirements into its SIP programs 

which were sufficient to offset the 

increased emissions anticipated as a 

result of removing the I/M program from 

the active SIP. This type of equivalency 

analysis was not provided by Alabama 

and we cannot conclude in this case 

that the status quo air quality will be 

maintained. Rather, in the case of 

Alabama, EPA judges that there is more 

than a remote possibility for increased 

emissions under the SIP revision and 

that our current action is consistent 

with the KRC case. 

Comment 45. Commenters make a 

distinction between attainment and 

nonattainment areas for purposes of a 

110(l) analysis. Commenters appear to 

suggest that because Alabama had no 

outstanding nonattainment plans due in 

the time frame of the October 15, 2008, 

final rule, that the 110(l) analysis should 

address whether the revision would 

affect the status quo. 

Response 45. EPA agrees that the 

110(l) analysis for a nonattainment area 

should, in the absence of an attainment 

demonstration, assure at least that the 

status quo is maintained. Thus, EPA 

will generally not approve a SIP 

revision that allows additional 

emissions of pollutants for which an 

area is designated nonattainment in the 

absence of offsetting reductions. 

Because EPA now concludes that 

Alabama’s SIP revisions are likely to 

result in an increase in PM emissions, 

for which parts of Alabama are 

designated nonattainment, it cannot be 

approved consistent with section 

110(l).21 While EPA has previously 

required a more robust 110(l) analysis 

for nonattainment areas, there is still an 

analysis required for attainment areas. 

Section 110(l) applies to all SIP 

revisions, regardless of whether the 

revision is impacting attainment areas 

or nonattainment areas. Alabama’s 

visible emissions rule at issue is part of 

Alabama’s plan to attain and maintain 

the NAAQS. The analysis under 110(l) 

does not depend on what SIP revisions 

are currently due, although 110(l) 


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requires EPA to consider other 

applicable requirements in the SIP. 

Comment 46. Commenters explained 

that because they believe that there is no 

relationship between opacity and PM, 

the inquiry as to 110(l) could end there. 

Commenters also argued against 

substituting the words ‘‘could interfere’’ 

for ‘‘would interfere’’ in 110(l). 

Response 46. EPA does not agree that 

there is no relationship between opacity 

and PM emissions. Rather, EPA 

concludes that there is a general 

relationship between opacity and PM 

emissions, but for a specific source and 

its operating characteristics, there is 

uncertainty about whether increases in 

opacity are accompanied by increases in 

PM emissions without examination of 

each source at issue. In addition, EPA 

does not substitute the words ‘‘could 

interfere’’ for ‘‘would interfere’’ in 

interpreting and applying 110(l). For 

any given source at any given time, it is 

accurate to say that increased opacity 

could be accompanied by increased PM 

emissions. However, in evaluating what 

would be allowed under the Submittals 

across all sources and circumstances, 

EPA concludes it is likely that the 

increased opacity allowed by the 

Submittals would result in increased 

PM emissions. EPA judges the 

significant increase in the flexibility in 

the opacity exemptions allowed to 

sources under the revised rule is great 

enough that, absent a convincing 

demonstration otherwise, the Agency 

may only conclude the revised rule 

hinders (i.e., ‘‘would interfere’’ with) 

efforts to attain and maintain 

compliance with the PM NAAQS. 

Comment 47. Commenters explained 

that changes to Alabama’s Visible 

Emission Rule do not affect compliance 

with PM limits. According to the 

commenter, Alabama has not relied on 

opacity limits to demonstrate attainment 

with the PM NAAQS. Thus, the 

commenter argued that section 110(l) 

does not apply here at all. 

Response 47. Section 110(l) applies, 

by its plain text, to all SIP revisions 

including Alabama’s 2003 and 2008 

Submittals. Contrary to the commenter’s 

belief, the State has historically 

included the visible emissions rules in 

its SIP for purposes of attainment and 

maintenance of the PM NAAQS. The 

fact that the State may not have sought 

specific SIP credit attributable to the 

opacity limits (not to be confused with 

SIP credit for the PM limits that such 

opacity limits are designed to assure 

compliance with) does not mean that 

the opacity limits are not part of the SIP. 

Comment 48. Commenters explained 

that 110(l) does not require absolute 

certainty regarding interference with 

attainment and maintenance of the 

NAAQS. According to the commenters, 

EPA has never taken that position and 

it would be a departure from Agency 

practice to take such a position. 

Commenters cited to KRC v. EPA, 467 

F.3d 986 (6th Cir. 2006) and GalvestonHouston Ass’n for Smog Prevention 

(GHASP) v. EPA, 289 Fed. Appx. 745 

(5th Cir. 2008). Commenters concluded 

that EPA cannot rely on mere 

uncertainty as a basis for disapproving 

a SIP revision. 

Response 48. EPA agrees that section 

110(l) does not require absolute 

certainty. EPA’s decision today relies on 

certainties concerning the impacts of the 

revisions to Alabama’s visible emissions 

rules in the Submittals. These 

certainties include that the Alabama 

rule would allow for increase of 

maximum opacity from 40 percent to 

100 percent and would allow such 

increases for up to 2.4 hours at a time, 

instead of for only six minutes per hour. 

EPA is disapproving the revision 

because while there are uncertainties— 

such as precisely when PM mass 

emissions would increase or by what 

precise amount—EPA expects that it is 

likely in at least some circumstances to 

result in increases in PM mass 

emissions. EPA generally, absent an 

attainment demonstration or offsetting 

emission reductions, will not approve a 

SIP revision that results in increases in 

emissions of a pollutant for which an 

area is designated nonattainment 

pursuant to the requirements of section 

110(l). EPA has already discussed the 

KRC case in a previous response. The 

GHASP case supports EPA’s position in 

this action because that was another 

case where the court upheld EPA’s 

interpretation that section 110(l) 

requires that a SIP revision must at least 

maintain status quo air quality to be 

approvable. 

8. CAA Section 110(l) ‘‘Demonstration’’ 

of Non-Interference With the NAAQS 

and Other Requirements 

Comment 49. Commenters argued that 

it is not clear what EPA means when it 

says that ‘‘Alabama has not provided 

EPA with an affirmative demonstration 

that the [Rule] will not interfere with 

the attainment and maintenance of the 

NAAQS’’ (74 Fed. Reg. at 50933), since, 

in the commenters’ view, that is exactly 

what the 2008 revision adding the 22 

percent daily average cap ensures. 

Commenters further stated that to 

require Alabama to provide more than 

the modeling of its 2003 submittal 

would be contrary to what the CAA 

requires and would be essentially asking 

for the impossible given the 

acknowledged uncertainty between 

opacity and PM, particularly for shortterm analysis. 

Response 49. EPA does not agree with 

the commenters’ interpretation of 110(l) 

or characterization of what was 

provided to EPA. As was explained 

above, EPA has concluded that the 

interpretation of 110(l) that is most 

consistent with the plain text, legislative 

history, and air quality goals of the CAA 

is that in order to approve the SIP 

revision, there must be some reasonable 

basis for concluding that the SIP 

revision will not interfere with 

attainment or maintenance of the 

NAAQS, consistent with the 

requirements of 110(l). As commenters 

acknowledged, the evaluation for this 

particular SIP revision is challenging 

due to the inherent uncertainty in the 

relationship between opacity and PM 

mass emissions at a given source. For 

this reason, it is even more important 

that the demonstration be sufficient to 

ensure that EPA is complying with 

section 110(l). 

A fundamental purpose of 110(l) is to 

allow SIP revisions in the absence of a 

full attainment demonstration provided 

that such revisions are consistent with 

continued attainment and maintenance 

of the NAAQS. To the extent that 

emission increases of a particular SIP 

revision cannot be modeled with some 

level of certainty regarding impact on 

the NAAQS, section 110(l) may bar that 

SIP revision, absent equivalent 

offsetting emissions reductions and in 

the absence of an attainment or 

maintenance demonstration. In EPA’s 

judgment, the analysis submitted in 

connection with the SIP revisions at 

issue here fails to provide a reasonable 

basis on which to conclude that the 

changes would not interfere with 

attainment and maintenance of the 

NAAQS. EPA concludes that the CAA 

prohibits this SIP revision because air 

emissions could be allowed to increase 

and thus, worsen air quality in 

nonattainment areas. 

Comment 50. Commenters argued that 

there is no basis for reversing EPA’s 

prior analysis because the current SIP 

ensures opacity will be equal to or lower 

than that allowed under the previous 

SIP. Commenters further stated that EPA 

demonstrated mathematically that both 

the suggested changes in its 2007 

proposal to approve the Rule and in 

Alabama’s 2008 revisions as submitted 

are at least as stringent as Alabama’s 

existing SIP and even more stringent 

than the 2003 revisions. 

Response 50. As discussed above, 

EPA has concluded after 

reconsideration that it is not appropriate 

to measure the stringency of the SIP 

revisions in the Submittals using an 


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‘‘average daily limit.’’ Alabama’s revised 

rule allows for extended periods of 

operation at high levels of opacity that 

were not previously authorized. Absent 

a showing that a source’s PM emissions 

would not be elevated if it was 

permitted to have opacity at up to 100 

percent for up to 2.4 hours a day, EPA 

has concluded that the SIP revisions 

would be inconsistent with section 

110(l). 

Comment 51. Commenters argued that 

Alabama has made an affirmative 

demonstration that the visible emissions 

standards in the previous SIP and the 

revised SIP are equivalent. Alabama’s 

previous visible emissions rule allowed 

opacity of up to 40 percent for one sixminute period per hour. The revised 

rule allows the same maximum time of 

higher opacity in a single day (up to 144 

minutes per day), but eliminates the 40 

percent cap. To assure equivalency with 

the previous rule, the revised SIP limits 

the daily average opacity to less than 22 

percent. The basis for derivation of the 

22 percent limit was clearly set out in 

EPA’s final rule. 73 FR at 60958–59 

(October 15, 2008). 

Response 51. As explained above, as 

a result of this reconsideration EPA 

disagrees that the two versions of the 

visible emissions rules could be 

equivalent, as explained in detail in the 

Rule Comparison TSD included in the 

docket. Ultimately, if the impacts of the 

two versions were actually equivalent, 

there would be no reason for Alabama 

to seek the SIP revisions. The practical 

reality is that the revised rule allows for 

opacity increases not previously 

authorized (both in concentration and 

quantity of time). Furthermore, the rule 

at issue specifically affects facilities 

which for one reason or another are not 

subject to any other opacity limit—and 

thus this opacity limit is particularly 

important both for air quality and as an 

indicator of facility O & M. While EPA 

understands the commenters’ concerns, 

EPA does not agree that the two 

versions of the visible emissions rules 

are equivalent. 

Comment 52. One commenter stated 

that EPA’s approval was entirely 

consistent with section 110(l). 

According to the commenter, EPA made 

an ‘‘appropriate inquiry’’ under section 

110(l) to protect the NAAQS because it 

made an equivalency determination and 

did not rely solely on uncertainty as a 

basis for the approval. This commenter 

believes that any uncertainty is erased 

by the 22 percent cap. 

Response 52. EPA’s October 15, 2008, 

final action relied heavily on the 

uncertainty inherent in the relationship 

between opacity and PM mass 

emissions. The October 15, 2008, action 

was different from other 110(l) analyses 

previously completed by EPA for that 

reason. EPA agrees that this rule 

presents particularly complex technical 

issues but has ultimately decided that 

heavy reliance on uncertainty as a basis 

for approval is not the decision most 

consistent with the CAA. Section 110(l) 

is intended to preclude SIP revisions 

that could have adverse consequences 

for public health, and accordingly EPA 

thinks that it should continue to 

interpret the provision using a 

precautionary principle to ensure such 

public health protection in the face of 

uncertainty about the impacts of a SIP 

revision. 

Comment 53. Commenters drew 

comparisons between Ohio’s recent 

opacity proposal and North Carolina’s 

previous opacity proposal and 

concluded that Alabama’s opacity limits 

are far below those of other states 

(specifically, North Carolina and 

Georgia). 

Response 53. EPA does not agree with 

commenters’ assessment of opacity 

requirements in other states. Alabama’s 

revised rule was unique in that it allows 

opacity of up to 100 percent (not 

allowed under the recent North Carolina 

revisions)—and it allows such opacity 

for up to 2.4 consecutive hours. Opacity 

revisions, by nature, require detailed 

case-by-case analyses. Due to the 

specific circumstances of a state (i.e., 

attainment status, affected facilities, 

topography, etc...), it is difficult to 

directly compare opacity rules from 

state to state (or SIP to SIP). While 

previous opacity decisions are 

informative, no other state presents a 

circumstance totally analogous to 

Alabama’s circumstances. In addition, 

EPA has proposed to disapprove 

comparable revisions to the visible 

emissions rules in the Ohio SIP for 

reasons comparable to those described 

in this final action. 

9. Use of COMS and Need for 

Exemptions 

Comment 54. One commenter argued 

that without a regulatory mechanism to 

address excess emissions reported from 

COMS, such as that used by Alabama, 

sources are vulnerable to enforcement 

actions for short term opacity 

excursions that have negligible 

environmental effects. 

Response 54. The environmental 

effect of individual ‘‘short-term’’ opacity 

excursions depends upon the duration 

and level of such exceedances, as well 

as the relationship between opacity and 

PM emissions at the source where they 

occur. This is one reason why EPA has 

concluded that use of an ‘‘average daily 

opacity’’ cap, in which longer 

excursions at higher levels are allowed 

to be ‘‘averaged out’’ with periods of 

normal operation at lower opacity 

levels, does little to help reduce PM 

emissions. Therefore, an ‘‘average daily 

opacity cap’’ is not a sufficient basis to 

approve the proposed SIP revisions. 

Frequent recurrence of such events may 

reflect the need to improve source 

operation or emission controls in order 

to comply with the opacity limit, but 

that would be masked by the averaging 

effect of an average daily opacity 

standard. 

In the case of the visible emissions 

rule changes at issue in these SIP 

revisions, some sources may have to 

take action to improve their opacity 

performance in order to comply with 

the previous SIP rule. Finally, today’s 

action does not impede the State’s 

ability to exercise its own enforcement 

discretion in the event that it decides a 

given opacity violation does not warrant 

such action. 

Comment 55. Commenters explained 

that when utilizing COMS that yield 

opacity data for nearly 100 percent of 

source operating time, given the 

extremely short data averages utilized 

for opacity data (six-minute data 

averages), time periods of excess occur 

from even the best operated sources. 

Response 55. EPA acknowledges that 

some sources may have difficulty in 

complying with 20 percent opacity 

limits 100 percent of the time, 

especially when events out of the 

source’s control occur, but EPA expects 

that all sources can comply with the 

pre-existing version of the visible 

emissions rule that will be in place as 

a result of today’s disapproval action. 

EPA expects that any unusual 

difficulties for specific sources would 

ease as sources subject to Alabama’s 

visible emissions rule take steps to 

improve their opacity performance. 

Comment 56. One commenter 

explained that 40 CFR 60.284(e) is the 

recognition by EPA that some type of 

exemption time period is necessary 

when opacity regulations are enforced 

by a continuous in-stack monitoring 

system and that this regulation is 

probably the basis of the Alabama SIP 

revisions. The commenter further 

explained its view that the ‘‘the 

preamble to both the NSPS (40 CFR 

60.7(c)) and the MACT [maximum 

achievable control technology] (40 CFR 

63.10(e)(3))’’ both state that sources 

required to submit reports of excess 

emissions from continuous in-stack 

monitoring systems are only required to 

submit summary reports of the excess 

emissions data and not detailed reports, 

provided that the total duration of 

excess is less than one percent of the 


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total operating time of the monitored 

source for the operating time period and 

that the monitor downtime is less than 

five percent of the total operating time 

of the monitored source for the 

reporting time period. The commenter 

considered these two regulations as a 

‘‘de facto’’ recognition by EPA of [the 

need for] exemption time periods 

similar to that proposed in the Alabama 

SIP revisions. 

Response 56. EPA disagrees with the 

premise of the comment, as it misses the 

mark concerning what is relevant in the 

context of a SIP revision for purposes of 

section 110(l). The NSPS and SIPs serve 

different purposes under the CAA. The 

NSPS are industry-specific nationally 

uniform air emission standards that 

limit the amount of emissions allowed 

from new sources or from modified 

existing sources. They are technologybased standards, meaning that they 

contain industry-specific limitations 

based on the best available technology. 

Under section 111 of the CAA, a 

standard of performance must reflect the 

degree of emission limitation and the 

percentage reduction achievable 

through application of the best 

technological system of continuous 

emission reduction that the 

Administrator determines has been 

adequately demonstrated. Such 

determinations take into consideration 

the cost of achieving such emission 

reduction and any non-air quality health 

and environmental impact and energy 

requirements. The fact that such 

standards contain various reporting 

requirements about excess emissions 

does not address the issues relevant to 

an analysis to support a SIP revision. 

SIPs are EPA-approved state plans for 

the establishment, regulation, and 

enforcement of air pollution standards— 

the NAAQS. Under section 110 of the 

Act, each state must adopt a plan to 

provide for implementation, 

maintenance, and enforcement of the 

primary and secondary NAAQS within 

the state. Because SIPs serve a different 

purpose than the NSPS, EPA evaluates 

them differently. For example, the NSPS 

provide exemptions from compliance 

during brief periods such as startup, 

shutdown, and malfunctions (SSM). 

Such automatic exemptions are not 

appropriate for SIP rules because SIPs 

are ambient-based standards and any 

emissions above the allowable may 

cause or contribute to violations of the 

NAAQS. Generally, because SIPs must 

provide for attainment and maintenance 

of the NAAQS and the achievement of 

prevention of significant deterioration 

increments, EPA’s policy is that all 

periods of excess emissions must be 

considered violations. SIPs can contain 

regulations with affirmative defenses for 

violations that occur due to events not 

reasonably within the control of the 

source, but they should not contain 

automatic exemptions. EPA’s policy 

with respect to appropriate SIP 

provisions is contained in the 1999 

memorandum entitled ‘‘State 

Implementation Plans (SIPs): Policy 

Regarding Excess Emissions During 

Malfunctions, Startup, and Shutdown.’’ 

Comment 57. Commenters explained 

that despite its best efforts, continuous 

compliance with the 20 percent opacity 

limit is an unachievable goal, and 

imposing penalties for failing to achieve 

an unattainable goal does not promote 

continuous, long term environmental 

improvement. 

Response 57. EPA’s final action does 

not impose penalties or implicate any 

specific enforcement actions. Rather, it 

simply finds that Alabama’s revisions to 

its visible emissions rule are not 

approvable under section 110(l) of the 

CAA. EPA encourages the commenter to 

discuss specific compliance concerns 

with ADEM. Sources should generally 

be capable of complying with the 

Alabama opacity rule, but we remain 

open to considering further SIP 

revisions that provide greater assurance 

that PM emissions will not increase as 

a result. 

10. Relationship of SIP Revisions to 40 

CFR 51.212 

Comment 58. Commenters argued that 

the visible emissions rule in the revised 

SIP is appropriate under 40 CFR 

51.212(b). Some commenters also 

discussed that the ‘‘indirect’’ use of 

COMS for compliance determinations 

adopted by Alabama and many other 

states is based on the approach adopted 

by EPA under the NSPS, which also 

specify Method 9 as the compliance 

method but require reporting of COMS 

data as an indicator of good control 

device O & M. The commenters asserted 

that because ADEM’s rule continues to 

use COMS data as an indicator of good 

O & M, but now simply provides an 

option for its use ‘‘directly * * * for 

compliance determinations,’’ respecting 

the independently enforceable opacity 

limit as allowed under Appendix P, the 

rule continues to meet EPA’s criteria. 

Other commenters highlighted the 

position that 51.212 provides states with 

discretion and the Alabama rule 

enhances enforcement through use of 

COMS. 

Response 58. In the present action, 

EPA is not evaluating the approvability 

of the SIP revision to Alabama’s visible 

emission rule revisions in light of the 

requirements of 40 CFR 51.212. While 

EPA agrees that this provision requires 

states to have SIPs with appropriate 

methods to assure compliance with 

emissions limits, EPA is not here 

addressing whether the revisions at 

issue would or would not meet those 

requirements. EPA’s analysis for the 

present action focused on the section 

110(l) limitations on EPA’s authority to 

approve a SIP revision. Even if 

Alabama’s revised visible emissions rule 

were consistent with section 51.212, 

this would not alleviate the concerns 

that EPA has with respect to section 

110(l). 

Comment 59. Commenters stated that 

ADEM’s two percent criterion is 

consistent with policies developed by 

EPA in the 1980s to support the use of 

continuous monitors. Commenters 

noted that there is no national standard 

on visible emissions and ADEM’s use of 

a flexible approach is consistent with 

part 51. 

Response 59. In the present 

rulemaking, EPA is not articulating a 

position on ADEM’s enforcement 

discretion or policies regarding 

enforcement discretion, although EPA is 

aware of the fairly recent Eleventh 

Circuit Court’s opinion addressing 

ADEM’s enforcement discretion in a 

visible emissions context. As was 

explained earlier, EPA acknowledges 

the various comments that support 

ADEM’s Submittals by citing to other 

federal requirements. However, EPA’s 

analysis was focused on its authority 

under section 110, and the review of 

ADEM’s Submittals that is most 

supported by the CAA. 

11. Relationship of SIP Revisions to 

Compliance Assurance Monitoring 

(CAM) Rule 

Comment 60. Commenters explained 

that although Alabama’s visible 

emissions rule may have some role in 

evaluating long-term PM control device 

operation, it is no longer the primary 

means by which major sources assure 

compliance with SIP limits on PM. 

Commenters believe that this role is 

now filled by EPA’s CAM rule at 40 CFR 

part 64. 

Response 60. EPA’s present action is 

not dependent upon whether the State’s 

visible emissions rule is the ‘‘primary’’ 

means for evaluating compliance with 

PM limits, although that has been and 

continues to be a legitimate reason for 

such opacity limits in SIPs. EPA’s 

present action is based primarily on its 

obligation under section 110(l) not to 

approve SIP revisions that would 

interfere with attainment or 

maintenance of the NAAQS or other 

applicable requirements of the CAA. 

EPA agrees that the CAM rule provides 

additional support for evaluation of 


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control device operation; however, CAM 

applicability and methodologies vary 

from facility-to-facility. The CAM rule is 

designed to provide reasonable 

assurance of ongoing compliance with 

applicable emissions limits, such as the 

PM emission limits of the SIP. But CAM 

requirements are in addition to the 

requirements of Alabama’s visible 

emissions rule; as a result, the 

commenters’ statements do not resolve 

whether the revisions to the visible 

emissions rule satisfy section 110(l). 

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 

Comment 61. Commenters explained 

that the D.C. Circuit Court’s vacatur of 

40 CFR part 63 provisions pertaining to 

SSM and its impact on the opacity SIP 

revision are irrelevant. Further, 

commenters noted that SSM provisions 

are not at issue in the instant SIP 

revision. 

Response 61. EPA does not agree with 

the blanket statement that SSM 

provisions are not at issue in the instant 

SIP revision. As part of EPA’s 110(l) 

evaluation, EPA may consider the SIP as 

a whole—including other provisions, 

such as SSM provisions, that may 

further affect the consequences of a 

given SIP revision. In this case, EPA’s 

analysis focused primarily on the 

provisions of the visible emissions rule 

that the State actually sought to change 

in the Submittals. However, EPA may 

consider the entirety of a rule, and the 

SIP, in completing a 110(l) analysis. 

13. Relationship of SIP Revisions to 

Reasonably Available Control 

Technology (RACT) 

Comment 62. Commenters explained 

that the Submittals on opacity are not 

required to comply with RACT and that 

there is no requirement for EPA to 

review ‘‘unrelated SIP revisions 

requests’’ for future RACT compliance. 

Moreover, commenters stated that when 

Alabama does submit a SIP revision to 

address RACT, EPA is not compelled to 

require that revision to establish any 

particular opacity standard. Another 

commenter stated that Alabama’s 

revised SIP imposes the proper opacity 

RACT standard. Several commenters 

noted that the Petitioners will have 

separate opportunity to challenge RACT 

determinations is RACT-specific 

rulemaking. 

Response 62. RACT refers to 

equipment and practices that reduce 

pollutant emissions that are reasonably 

available and both technologically and 

economically feasible. RACT usually 

applies to existing sources in 

nonattainment areas. Since EPA has 

concluded that this revision is not 

approvable under section 110(l) for the 

reasons already stated, it is not 

necessary to determine whether 

Alabama has relied on opacity limits to 

meet its RACT obligations. 

Notably, section 172 of the Act, 

Nonattainment plan provisions in 

general, requires nonattainment plans 

‘‘shall provide for the implementation of 

all reasonably available control 

measures as expeditiously as practicable 

(including such reductions in emissions 

from existing sources in the area as may 

be obtained through the adoption, at a 

minimum, of reasonably available 

control technology) and shall provide 

for attainment of the national primary 

ambient air quality standards.’’ Section 

172 requirements, including RACT, are 

applicable requirements of the CAA 

which section 110(l) evaluations may 

consider. 

Section 110(l) requires that EPA 

consider whether the revision at issue 

would interfere with the NAAQS, and 

any other applicable requirement 

concerning attainment and RFP. Thus, 

EPA is authorized to consider whether 

the revision would interfere with an 

area’s ability to comply with RACT or 

other requirements in the SIP. In this 

case, however, EPA’s review was 

primarily focused on interference with 

the NAAQS. While some applicable 

requirements may be subject to separate 

SIP revisions, as was noted by several 

commenters, that does not mean that 

EPA is prohibited from considering 

whether revision of a rule at issue may 

implicate another applicable 

requirement. RACT issues are likely to 

also be addressed separately in other 

SIP revisions. 

14. Other Exemptions in Alabama SIP 

Related to Visible Emissions 

Comment 63. Commenters noted that 

EPA’s final action was not inconsistent 

with EPA policies on excess emissions 

and director’s discretion. 

Response 63. As was previously noted 

by EPA in the 2007 proposal and the 

October 2008, action, the director’s 

discretion provisions under Alabama 

rule 335–3–4–.01(1)(c) and (d) are 

unchanged by the SIP revisions. As a 

result, periods of excess emissions 

allowed in a permit pursuant to those 

provisions remain unchanged under 

Alabama’s rules. EPA did, however, 

consider Alabama’s provisions for 

excess emissions in evaluating the rule 

as a whole and comparing it with the 

previous EPA-approved SIP rule. These 

types of details become relevant, 

particularly when parties compare 

Alabama’s visible emissions rules with 

those in other states. In this action, EPA 

is not taking any action on Alabama’s 

existing SIP-approved rules that 

implicate director’s discretion and 

excess emissions. 

IV. Final Action 

EPA is taking final action to amend an 

October 15, 2008, final rulemaking on 

two 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 

CAA section 110(l). Accordingly, EPA is 

now disapproving the revisions 

submitted by the State of Alabama on 

September 11, 2003, and August 22, 

2008. 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. Alabama is urged to 

undertake rulemaking in order to 

conform its SIP-approved rule with its 

State-effective rule. 

V. Statutory and Executive Order 

Reviews 

A. Executive Order 12866, Regulatory 

Planning and Review 

This final action has been determined 

to be a ‘‘significant regulatory action’’ 

subject to review by the Office of 

Management and Budget (OMB) under 

Executive Order 12866 (58 FR 51735, 

October 4, 1993). Accordingly, EPA 

submitted this action to the Office of 

Management and Budget (OMB) for 

review under Executive Order 12866 

and any changes made in response to 

OMB recommendations have been 

documented in the docket for this 

action. 

B. Paperwork Reduction Act 

This action does not impose an 

information collection burden under the 

provisions of the Paperwork Reduction 

Act, 44 U.S.C. 3501 et seq., because 

these SIP disapprovals under section 

110 will not in-and-of itself create any 

new information collection burdens but 

simply disapproves certain State 

requirements for inclusion into the SIP. 

Burden is defined at 5 CFR 1320.3(b). 

C. Regulatory Flexibility Act (RFA) 

The RFA generally requires an agency 

to conduct a regulatory flexibility 

analysis of any rule subject to notice 

and comment rulemaking requirements 

unless the agency certifies that the rule 

will not have a significant economic 

impact on a substantial number of small 

entities. Small entities include small 

businesses, small not-for-profit 


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enterprises, and small governmental 

jurisdictions. For purposes of assessing 

the impacts of today’s rule on small 

entities, small entity is defined as: (1) A 

small business as defined by the Small 

Business Administration’s regulations at 

13 CFR 121.201; (2) a small 

governmental jurisdiction that is a 

government of a city, county, town, 

school district or special district with a 

population of less than 50,000; and (3) 

a small organization that is any not-forprofit enterprise which is independently 

owned and operated and is not 

dominant in its field. This rule will not 

have a significant impact on a 

substantial number of small entities 

because EPA understands that only one 

small entity will be affected by this rule. 

Furthermore, even if additional small 

entities were affected by this rule, this 

rule would not have a significant 

economic impact on any small entity 

because it simply restores a longstanding requirement of the Alabama 

SIP concerning visible emissions. 

Therefore, after considering the 

economic impacts of today’s rulemaking 

on small entities, I certify that this 

action will not have a significant 

economic impact on a substantial 

number of small entities. 

D. Unfunded Mandates Reform Act 

This action contains no Federal 

mandates under the provisions of Title 

II of the Unfunded Mandates Reform 

Act of 1995, 2 U.S.C. 1531–1538 ‘‘for 

State, local, or tribal governments or the 

private sector.’’ EPA has determined that 

the disapproval action does not include 

a Federal mandate that may result in 

estimated costs of $100 million or more 

to either State, local, or tribal 

governments in the aggregate, or to the 

private sector. This Federal action 

determines that pre-existing 

requirements under State or local law 

should not be approved as part of the 

Federally approved SIP. It imposes no 

new requirements. Accordingly, no 

additional costs to State, local, or tribal 

governments, or to the private sector, 

result from this action. 

E. Executive Order 13132, Federalism 

Executive Order 13132, entitled 

‘‘Federalism’’ (64 FR 43255, August 10, 

1999), requires EPA to develop an 

accountable process to ensure 

‘‘meaningful and timely input by State 

and local officials in the development of 

regulatory policies that have Federalism 

implications.’’ ‘‘Policies that have 

Federalism implications’’ is defined in 

the Executive Order to include 

regulations that have ‘‘substantial direct 

effects on the States, on the relationship 

between the national government and 

the States, or on the distribution of 

power and responsibilities among the 

various levels of government.’’ 

This action does not have Federalism 

implications. It will not have substantial 

direct effects on the States, on the 

relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government, as specified in 

Executive Order 13132, because it 

merely disapproves certain State 

requirements for inclusion into the SIP 

and does not alter the relationship or 

the distribution of power and 

responsibilities established in the CAA. 

Thus, Executive Order 13132 does not 

apply to this action. 

F. Executive Order 13175, Coordination 

With Indian Tribal Governments 

This action does not have tribal 

implications, as specified in Executive 

Order 13175 (59 FR 22951, November 9, 

2000), because the SIP EPA is 

disapproving would not apply in Indian 

country located in the State, and EPA 

notes that it will not impose substantial 

direct costs on tribal governments or 

preempt tribal law. This final rule does 

not have tribal implications, as specified 

in Executive Order 13175. It will not 

have substantial direct effects on tribal 

governments, on the relationship 

between the Federal government and 

Indian tribes, or on the distribution of 

power and responsibilities between the 

Federal government and Indian tribes. 

This action does not involve or impose 

any requirements that affect Indian 

Tribes. Thus, Executive Order 13175 

does not apply to this action. 

G. Executive Order 13045, Protection of 

Children From Environmental Health 

Risks and Safety Risks 

EPA interprets Executive Order 13045 

(62 FR 19885, April 23, 1997) as 

applying only to those regulatory 

actions that concern health or safety 

risks, such that the analysis required 

under section 5–501 of the Executive 

Order has the potential to influence the 

regulation. This action is not subject to 

Executive Order 13045 because it is not 

an economically significant regulatory 

action based on health or safety risks 

subject to Executive Order 13045 (62 FR 

19885, April 23, 1997). This SIP 

disapproval under section 110 will not 

in-and-of itself create any new rules but 

simply disapproves certain State 

requirements for inclusion into the SIP. 

H. Executive Order 13211, Actions That 

Significantly Affect Energy Supply, 

Distribution, or Use 

This action is not a ‘‘significant energy 

action’’ as defined in Executive Order 

13211 (66 FR 28355 (May 22, 2001)), 

because it is not likely to have a 

significant adverse effect on the supply, 

distribution, or use of energy. We have 

concluded this rule is not likely to have 

a significant adverse effect on the 

supply, distribution or use of energy 

because this rule applies only to 19 

facilities in Alabama and simply 

restores a long-standing rule concerning 

visible emissions. 

I. National Technology Transfer and 

Advancement Act (NTTAA) 

Section 12(d) of the NTTAA of 1995 

(NTTAA), Public Law 104–113, section 

12(d) (15 U.S.C. 272 note) directs EPA 

to use voluntary consensus standards 

(VCS) in its regulatory activities unless 

to do so would be inconsistent with 

applicable law or otherwise impractical. 

VCS are technical standards (e.g., 

materials specifications, test methods, 

sampling procedures, and business 

practices) that are developed or adopted 

by VCS bodies. NTTAA directs EPA to 

provide Congress, through the OMB, 

explanations when the Agency decides 

not to use available and applicable VCS. 

EPA believes that this action is not 

subject to requirements of Section 12(d) 

of NTTAA because application of those 

requirements would be inconsistent 

with the CAA. Today’s action does not 

require the public to perform activities 

conducive to the use of VCS. 

J. Executive Order 12898: Federal 

Actions To Address Environmental 

Justice in Minority Populations and 

Low-Income Populations 

Executive Order 12898 (59 FR 7629, 

(February 16, 1994)) establishes Federal 

executive policy on environmental 

justice. Its main provision directs 

Federal agencies, to the greatest extent 

practicable and permitted by law, to 

make environmental justice part of their 

mission by identifying and addressing, 

as appropriate, disproportionately high 

and adverse human health or 

environmental effects of their programs, 

policies, and activities on minority 

populations and low-income 

populations in the United States. 

EPA lacks the discretionary authority 

to address environmental justice in this 

action. In reviewing SIP submissions, 

EPA’s role is to approve or disapprove 

State choices, based on the criteria of 

the CAA. Accordingly, this action 

merely disapproves certain State 

requirements for inclusion into the SIP 


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Federal Register / Vol. 76, No. 66 / Wednesday, April 6, 2011 / Rules and Regulations 18893 

under section 110. Accordingly, it does 

not provide EPA with the discretionary 

authority to address, as appropriate, 

disproportionate human health or 

environmental effects, using practicable 

and legally permissible methods, under 

Executive Order 12898. 

K. Congressional Review Act 

The Congressional Review Act, 5 

U.S.C. 801 et seq., as added by the Small 

Business Regulatory Enforcement 

Fairness Act of 1996, generally provides 

that before a rule may take effect, the 

agency promulgating the rule must 

submit a rule report, which includes a 

copy of the rule, to each House of the 

Congress and to the Comptroller General 

of the United States. EPA will submit a 

report containing this rule and other 

required information to the U.S. Senate, 

the U.S. House of Representatives, and 

the Comptroller General of the United 

States prior to publication of the rule in 

the Federal Register. A major rule 

cannot take effect until 60 days after it 

is published in the Federal Register. 

This action is not a ‘‘major rule’’ as 

defined by 5 U.S.C. 804(2). This rule 

will be effective May 6, 2011. 

L. Petitions for Judicial Review 

Under section 307(b)(1) of the CAA, 

petitions for judicial review of this 

action must be filed in the United States 

Court of Appeals for the appropriate 

circuit by June 6, 2011. Filing a petition 

for reconsideration by the Administrator 

of this final rule does not affect the 

finality of this rule for the purposes of 

judicial review nor does it extend the 

time within which a petition for judicial 

review may be filed, and shall not 

postpone the effectiveness of such rule 

or action. This action may not be 

challenged later in proceedings to 

enforce its requirements. See CAA 

section 307(b)(2). 

List of Subjects in 40 CFR Part 52 

Environmental protection, Air 

pollution control, Carbon monoxide, 

Incorporation by reference, 

Intergovernmental relations, Lead, 

Nitrogen dioxide, Ozone, Particulate 

matter, Reporting and recordkeeping 

requirements, Sulfur oxides, Volatile 

organic compounds. 

Dated: March 29, 2011. 

Gwendolyn Keyes Fleming, 

Regional Administrator, Region 4. 

40 CFR part 52 is amended as follows: 

PART 52—[AMENDED] 

■ 1. The authority citation for part 52 

continues to read as follows: 

Authority: 42 U.S.C. 7401 et seq. 

Subpart B—Alabama 

■ 2. Section 52.50(c) is amended by 

revising the entry for ‘‘Section 335–3–4– 

.01’’ to read as follows: 

§ 52.50 Identification of plan. 

* * * * * 

(c) * * * 

EPA-APPROVED ALABAMA REGULATIONS

State citation Title/subject State effective 

date EPA approval date Explanation 

*******

Section 335–3–4–.01 ................... Visible Emissions ......................... 10/15/1996 4/6/2011 [Insert citation of 

publication].

* * * * * * * 

* * * * * 

[FR Doc. 2011–8032 Filed 4–5–11; 8:45 am] 

BILLING CODE 6560–50–P 

ENVIRONMENTAL PROTECTION 

AGENCY 

40 CFR Part 52 

[EPA–R05–OAR–2010–0259; FRL–9285–4] 

Approval and Promulgation of Air 

Quality Implementation Plans; Ohio; 

Volatile Organic Compound Emission 

Control Measures for Lithographic and 

Letterpress Printing in Cleveland 

AGENCY: Environmental Protection 

Agency (EPA). 

ACTION: Final rule. 

SUMMARY: EPA is approving into the 

Ohio State Implementation Plan (SIP) 

revisions to its previously approved 

offset lithographic and letterpress 

printing volatile organic compound 

(VOC) rule. These rule revisions specify 

compliance dates for subject facilities 

using an add-on control device and 

recordkeeping requirements when a 

recipe log is maintained for each batch 

of fountain solution or cleaning 

solution. These rule revisions satisfy the 

requirements of reasonably available 

control technology (RACT) and the 

Clean Air Act (CAA). EPA proposed 

these rules for approval on December 

30, 2010, and received no comments. 

DATES: This final rule is effective on 

May 6, 2011. 

ADDRESSES: EPA has established a 

docket for this action under Docket ID 

Nos. EPA–R05–OAR–2010–0259. All 

documents in the docket are listed on 

the http://www.regulations.gov Web 

site. Although listed in the index, some 

information is not publicly available, 

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 

http://www.regulations.gov or in hard 

copy at the Environmental Protection 

Agency, Region 5, Air and Radiation 

Division, 77 West Jackson Boulevard, 

Chicago, Illinois 60604. This facility is 

open from 8:30 a.m. to 4:30 p.m., 

Monday through Friday, excluding 

Federal holidays. We recommend that 

you telephone Steven Rosenthal, 

Environmental Engineer, at (312) 886– 

6052 before visiting the Region 5 office. 

FOR FURTHER INFORMATION CONTACT: 

Steven Rosenthal, Environmental 

Engineer, Air Planning and 

Maintenance Section, Air Programs 

Branch (AR–18J), Environmental 

Protection Agency, Region 5, 77 West 

Jackson Boulevard, Chicago, Illinois 

60604, (312) 886–6052. 

SUPPLEMENTARY INFORMATION: 

Throughout this document whenever 

‘‘we,’’ ‘‘us,’’ or ‘‘our’’ is used, we mean 

EPA. This supplementary information 

section is arranged as follows: 

I. What public comments were received on 

the proposed approval and what is EPA’s 

response? 

II. What action is EPA taking today and what 

is the purpose of this action? 

III. Statutory and Executive Order Reviews 


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