SEP 201999 

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MEMORANDUM r;"". 0 " .'. (""") I 

'D -;-'1 

SUBJECT: State Implementation Plans: Policy Regarding E!<c,es~ i 

Emissions During Malfunctions, Startup, and Shrrrdo~ I 

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FROM: Steven' A. Herma 11 i ~: . Cf.1 , 

j~istant Admi' ,~ for Enforcement and CO~li~C~ 

&Assurance . 

Robert Perciasepe 

Assistant Administrator for Air and Radiation 

Regional Administrators, Regions I - X 

EPA's policy for state implementation plans (SIPs) regarding 

excess emissions during malfunctiorts, startup, shutdown, and 

maintenance is contained in memorartda from Kathleen Bennett, 

formerly Assistant Administrator f6r Air, Noise and Radiation I 

dated September 28, 1982 and FebruJry 15, 1983. A recent revie"( 

of. SIPs' suggests that several contJin provisions that appear to • 

be inconsistent with this policy, ~ither because they were ' 

inadvertently approved after EPA i~sued the.1982-1983 guidance or 

because they were part of the ~IP at that time and have never. 

been remo~ed. In order to address Ithese provipions in a 

consistent manner, today we are reaffirming and supplementing the 

1982~83 policy. In so doing, we aJe taking this opportunity to 

clarify several issues of interpretation that have arisen since I 

that time. The attached updated p6licy will clarify the types of 

excess emissions provisions states.lmay incorporate into SIPs so t 

that they can in turn provide greater certainty to the regulated 

conununi ty. . I ' . I 

As EPA stated in its 1982 ,memorandum, because excess 

emissions might aggravate air quality so as to prevent attainment 

or interfere with maintenance of the ambient air quality .1 

standards. EPA views all excess emissions as violations of the 

applicabie emission limitation.N~vertheless, EPA recognizes 

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that imposition of a penalty for sudden and unavoidable 

malftinctions cauied by circumstances entirely beyond the control 

of" the own'er' or operator may not' be ·a'ppropriate. Accordingly, a' 

state or EPA can exercise its "enforce!!lent,discretion" to refrain 

from taking an enforcement action in these,circumstances. 

The main question of interpretation that has arisen 

regarding the old policy is whether a state may go beyond this 

"enforcement discretion" approach and include in its SIP a 

provision that would, in.the context of an enforcement action for 

exces's emissions ,'-: excuse a sourc'e from penal ties if th,e source 

can demonstrate that it meets certain objective criteria (an 

"affirmative defense"). This policy clarifies that itates have 

'the discretion to provide 'such a defense to actions for.penalties 

brought for excess emissions that a~ise during certain 

malfunction, startup, and shutdown episodes, , 

In the coht;'ext of malfunctions" EPA recognizes that even 

eqUipment that is properly designed and maintained can sometimes 

fail. At the same time, EPA has a fundamental responsibility 

under the Clean Air Act to ensure that SIPs provide for 

attainment and maintenance of ' the national ambient air quality 

,standards ("NAAQS")and protection of PSD increments. Thus, EPA 

cannot approve an affirmative defense provision. that would 

undermine the fundamental requirement of attainment and 

maintenance of the NAAQS, or any other requirement of the Clean 

Air Act, See sections 110(a) and (1) of the Clean Air Act, 42 

U.S.C.S 7410(a) and (1).' Accordingly, an acceptable 

affirmative, defense provision ,may only appl~ to actions for 

penalties, out not to actions for injunctive relief. This 

restriction insures that both state and federal authorities 

remaTn able to 'protect air 'quality standards and PSD increments. 

Furthermore,' this approach is appropriate only when the 

respective, contributions of individual sources to pollutant 

concentrations in ambient' ai~· are such that .no single source or 

small-group' of 'sources has the potential to cahse an exceedance 

of the NAAQS ',or PSD increments.' Where a single source or small 

'Pursuant to Section 110 (1), EPA may not approve a SI'P 

revision if "the'icevision would interfere with any applicable' 

requirement concerning attainment and reasonable further 

progress, or any other applicable requirement of this chapter." 

See also CA1C§ 193, 42 U.B:C. § 7515, and the definitions of 

"emis'si'on"l'imitation" and "emission standard" contained in CAA 

§ 302(k), 42· d.s.c. § 7602(k). 

" In the case' of lead and sulfur dioxide, attainment 

problems usually are caused by one or a few sources and an 
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group of sources has the potential to cause an exceedance of the 

NAAQS or PSD increments, EPA believes an affirmative defense ! 

-apptba~h will not be adequat~ to p~otect public health and the 

environment, and the only appropri~te means of dealing with 

excess. emissions during malfunctiob, s~artup, and shutdown 

episodes is through an enforcement I discretion approach.) 

EPA is also taking this opportunity to clarify that it does 

not intend to approv~ SIP revision~ that would recognize a state 

director's decision to bar EPA's o~ citizens' ability to enforce 

ap~iicable requirements. Such an ~pproach would be inconsistent 

with the regulatory scheme establi~hed in Title I of the Clean i 

Air Act. EPA is also adding conte~poraneous record keeping and: 

notification criteria to make its ~olicy regarding these types of 

events consisteht with its enforcement approach. 

Finally, EPA is clarifying hol excess emissions that occur 

during periods of startup and shut~own should be addressed. In! 

general, because excess emissions that occur during these periods I ' 

are reasonably foreseeable, they should not be excused. However, 

EPA recognizes that, for some soud:e categories, even the best ! 

available emissions control system~ might not be consistently I 

effective during startup or shutdo*n periods. In areas where t~e 

respective contributions of individual sources to pollutant I 

concentrations '. in ambient air are ~uch that no single source or I small group of sources has the potential to cause an exceedance 

of the NAAQS or PSD increments, th~se technological limitations 

may be addressed in the underlying I standards themselves thLough 

narrowly-tailored SIP revisions that take into account the 

potential impacts on ambient air q0ality caused by the inclusion 

of these allowances. In thes. ins~ances, as part of its I 

justification of the SIP revision, the state should analyze the 

i 

affirmative defense is not approprtate. This situation can be 

particularly aggravated where a sh0rt-term standard (e.g., where 

exceedances or violations are based on a few hour period) is also 

in place. Although this policy is!generally applicable for other 

NAAQS, enforcement discretion is .the only appropriate approach. I 

for dealing with excess emissions during startup, shutdown, and 

malfunction in a specific area where a single source or a small 

group of sources has the potential to cause nonattainment of a 

short-term NAAQS. 

) In'American Trucking Association v. EPA, 175 F. 3d 1027 

(D.C. eirc., 1999), the court remartded the PM2.5 NAAQS to the 

EPA. The Agency has not determined whether this policy is 

appropriate for PM2.5 NAAQS. 
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impact of- the potential worst-'case emissions that could'occuI' 

during startup and shutdown.~ 

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In addition to this approach,states may address this problem 

through the use of enfo·rcement' discreeion or they may include a 

general affirmative defense provision in their SIPs for short and 

infrequent startup and shutdown periods along the lines outlined 

in theattachmept·.:· As mentioned above, however, in those areas 

where:'a ,single source or small group of sources has the potential 

to cause'am e}(ceedance of the NAAQS or PSD increments, issues 

relating to excess emissions arising during startUp and shutdown 

may only.: be addresse'dthrough an enforcement discretion approij.ch·. ~ --, 

All Regibns should review the·SIPs for their,states in light 

of this clarification and take -steps to 'insure that excess 

emissions provisions in these SIPs are consistent with the 

attached guidance., 

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A.ttachment 

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'States may account for such emissions by in'cluding them in 

their routine rule effectiveness estimates. Rule effectiveness 

estimates may be prepared in accordance with an EPA policy 

document entitled "Guidelines for Estimating and Applying 'Rule 

Effectiveness for Ozone/Carbon Monoxide State Implementation Plan 

Base Year Inventories." (EPA-452/R-92-010), November 1992. 

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Attachment 

I 

POLICY ON EXCESS EMISSIONS DURING MALFUNCTIONS, STARTUP, AND I SHUTDOWN . 

, Introduct·ion ., .. ·1- . _.·e 

This policy specifies when and·in what manner state 

implementation plans (SIPs) may pr6vide for defenses to 

viol'ations caused by· periods of exl::ess emis·sions due to 

malfunctions,' startup, or shutdow~. Generally, since SIPs must 

provide for attainment and mainten~nce of the national ambient ! 

air quality standards and the aChibvement of PSD increments, ali 

periods of ex6eSS emissions mu~t bb considered violations. , 

Accordingly, any provision that allows for an automatic 

exemption2 for· ex~ess emissions islprohibited. 

However, the imposition of a penalty for excess emissions 

during malfunctions caused by circbmstances entirely beyond the: 

control of the owner or operator m~y not be appropriate. States I 

may, therefore r as an exercise of their inherent enforcement 

discretion, choose not to penalizej a source that has produced 

excess emissions under such circumstances. 

This policy provides an alte~lative approach to enforcemen~ discretion for areas and pollutant~ where the respective I 

contributions of individual sourcek to pollutant concentrations I 

in ambient air are such that no sihgle source or small group of: 

sources has the potential to causej an exceedance of the NAAQS of 

PSD increments. Where a single source or small group of sources 

has the potential to cause an exce~dance of the NAAQS or PSD .! 

increments, as is often the case fbr sulfur dioxide and lead,' I 

EPA believes approaches other thanjenforcement discret~on are n~t 

appropriate. In such cases; any excess emissions may have a It 

significant chance of causing an ekceedance or violation of the . I, I 

applicable standard or PSD increment. ' 

'The term excess emission means an air emission level which 

exceeds any applicable:erilission litnitation. Malfunction means a 

sudden ,and unavoidable breakdown of process or controlequipmcn~_ 

2The term automatic exemption!means a generally applicable i 

provision in a SIP that would provide that if certain conditions 

existed during a period of excess ~missions, then those 

exceedances would not be considered violations. 

'This policy also does not apJlY for purposes of PM2.5 

NAAQS. In American Trucking Association v; EPA, 175 F. 3d 1027 

(D.C. Circ., 1999), the court remartded the PM2.5 NAAQS to the 

EPA. The Agency has not determined whether this policy is ~propriate for PM2.5 NAAQS. 
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Except where a single'source or small group of sources ,has 

the potential to cause an exceedance of the NAAQS or PSD 

:increments,sta,tes may include in, their, SIPs affirmative ""',' 

defenses' for excess emissions, as long as the SIP establishes 

limitations consistent with those set out below. If approved 

into a SIP, an affirmative defense would be available to sources 

in an enfoL'cement action seeki~g penalties brought by, the state, 

EPA, or citizens', ,Howeve,r, a determination by the state not to 

take an enforcement' actiQn would not' gar EPA or 'citizen action. 5 

In addition, in certain limited circumstances, .. {t may be' 

appropriate for the state to build into a source-specific ,or ' 

source-category-specific emission standard a provision stating, 

that the otherwise applicable emission limitations do not apply 

during narro~ly defined startup and shutdown periods. 

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I. '"AUTOMATIC EXEMPTIONS AND ENFORCEMENT DISCRETION 

If a SIP con~ains a, provision addre~sing exce~s emissions; 

it cannot be the type that providesfor'automatic exemptions. 

Automatic exemptions might aggravate ambient air quality by 

excus:j.!1gexc;:ess, emiss,ions that cause or contribute to a ,violation 

of an ambie!1t'air quality standard, Additional'grounds'for 

disapproving, a SIP, tha):. includes the automatic exemption approach 

are discuscsed'in more detaJl at 42 Fed. Reg. 58171 (November 8, 

1977) 'and,42·Fed. Reg.?1372 (April 27, 1977). As a,result, EPA 

will not approve any ~IP Fevision~ that provide automatic 

exemptions: for periods of excess, emissions. . , 

'. (" 

The best assurance that excess emission~ will,not interfere 

with NAAQS attainment, maintenance, or increments is to address 

excessemissi~ns through e~forcement discretion. This policy;,," 

provides alternative means for addressing excess emissions of ' 

criteria pollutants. However, 'this policy does not appi y where a 

single source or small group of sources has the potential to 

cause an exceedance of the NAAQS or PSD increments. Moreover, 

, , 

'The'term affii:-mative defense means, in the, context of an 

enforcement proceeding, a response or defense put forward by a 

defendant,regarding which the defendant has the bu~den of proof, 

and the merits of, which are, independently and objectively' 

evaluated in a judicial or administrative proceeding, • - .• • • i. 

5Because all periods of excess emissions are violations and 

because affirmative de~ense provisions may not apply in actions 

for injunctive relief, under no circumstances would EPA consider 

periods of excess emissions, even if covered by an affirmative 

defense, to be ." fed~rally permi.tted, releases" under EPCRA or ' 

CERCLA, 
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nothing in this guidance should be construed as requiring states 

to include affirmative defense provisions in their SIPs. - " " - -"" '. I'" -, ,. 

II. AFFIRMATIVE DEFENSES FOR MALFUNCTIONS 

EPA can approve a SIP revisiol that creates an affirmative 

defense to claims for penalties in!enforcement actions regarding 

excess emissions caused by malfunctions as long as the defense I 

does not apply to SIP provisions that derive from federally I 

promulgated performance standards 6r emission limits, such as new 

source performance standards (NSPS) and national emissions I 

standards for hazardous air pollutants (NESHAPS).' In addition, 

affirmative defenses are not appropriate for areas and pollutants 

where a single source or small group of sources has the potenti~l 

• to cause an exceedance of ,the NAAQS or PSD increments. I 

Furthermore, affirmative defenses to claims for injunctive reliJf 

are not allowed. To be approved, ~n affirmative defense ! 

provision must provide that the defendant has the burden of proof 

of demonstrating that: ~ 

1. The excess emissions were caused by a sudden, 

unavoidable breakdown of technology, -beyond the control of the 

owner or operator; , 

2. The excess emissions (a) did not stem from any activit1 

or event that could have been foreseen and avoided, or planned i 

for, and (b) could not have been a~oided by better operation and[ 

maintenance practices; I 

3. To the maximum extent pratticable the air pollution 

control equipment or processe5 wer~ maintained and operated in , manner consistent with good practice for minimizing emissions; 

4. Repairs were made in an expeditious fashion when the 

operator knew or should have known that applicable eciission 

limitations were being exceeded. Off-shift labor and overtime 

must have been utilized, to the extent practicable, to ensure 

that such repairs were made as expeditiously as practicable; , 

, . 5. The amount and duration of the excess emissions 

(including any bypass) were minimized to the maximum extent 

practicable during periods of such1emissions; , 

I 

I 

a 

'To the extent a state ,includes NSPS or NESHAPS in its SIP, 

the standards should not deviate from those that were federally 

promulgated. Because EPA set thes~ standards taking into account 

technological limitations, additiorta1 exemptions would be 

inappropriate. I 
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6. " A:ll' possible steps were taken to minimize the impact. of 

the excess emissions on ambient air quality; 

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7. All emission monitoring syste~s were kept in operation 

if at all possible; 

8. The owner or.operator's actions in response to the 

excess emi~sionswere documented by properly signed,· , 

contemporaneous operating logs, or other relevant evidence; 

9. ~heexcess emissions were not part of a ~ecurring 

pattern ihdicativeof inadequate 'design! operation, or 

maintenance; and 

10. The owner or operator properly and promptly notified 

the appropriate regulatory authority. 

EPA interprets these criteria narrowly. Only those 

malfunctions that are sudden, unavoidable, and unpredict~ble in 

nature qualify for the defense. For example, a single instance 

of a burst pipe that meets the above criteria may qualify under 

an affirmative ·defense. The defense would not be available, 

however, if the facility had a history of similar failures 

because of improper design, improper maintenance, or poor 

operating practices. Furthermore,.a source must have taken all 

available measures to compensate for and. resolve the malfunction. 

If a ~acility has a baghousefire that leads to excess emissions, 

the affirmative defense would be appropriate only for the period 

of time necessary to modify or curtail operations to come into 

compliance. The ·fire should-not be used to excuse excess 

emissions generated during an extended period of time while the 

operator orders and installs new bags, and relevant SIP language 

must limit applicability of the affirmative defense accordingly. 

III. EXCESS .EMISSIONS DURING STA~TU? AND SHUTDOWN 

In general, startup ·and shutdown of process equipment .are . 

part of the normal operation of a source and should be accounted 

for in the plannin'g, design,. and implementation of vperating 

procedures for the proce~s and control equipment. Accordingly, 

it is reasonable to expect, that careful and prudent planning ,and 

design will eliminaEe violations of emission limitations durin~ 

such periods. 

A. SOURCE CATEGORY SPECI FIC RULES ·FOR STARTUP AND SHUTDOWN 

" 

For some.source categories, given the types of control 

technologies available, there may exist short periods of . \ 

emissions during startup and shutdown when, despite best efforts 

~egarding planning, design, and operating prcicidures, the . 
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o therW1se ' app 1 1ca 'bl e em1SS10n .' l" 1m1tat10n I , cannot b e met. 

Accordingly, except in the case wh~re'a single source or,small 

group of sources has the potential I to" cause" 'an exce'edan:ce' 'ofth'e 

NAAQS or PSD increments, it may be:appzopriate, in consultation 

with EPA, to create narrowly-tailored ~IP revisions that take 

these technological limitations into account and state that the 

otherwise applicable emissions limitations do not apply during 

narrowly defined startup and shutd6wn periods. To be approved, 

these revisions should meet the following requirements: , ' 

" I. , . 1. The'revision must be limited to specific, narrowlydefined source categories using specific control strategies 

(e.g., cogeneration facilities burning natural gas and using 

,selective catalytic reduction); 

2. Use of, the 

must be technically 

periods; 

control strat~gy for this source category 

infeasible during startup or shutdown 

3. 

shutdown 

I 

The frequency and duratio~ of 

mode must be minimized toithe 

practicable; I 

, 

operation in startup or 

maximum extent 

4. As part of its justification of the SIP revision, the 

state should analyze the potential, worst-case emissions that 

could occur during startup and shutdown; 

5. All possible steps must be taken to minimize the impact 

of emissions during startup and shutdown on ambient air quality) 

6. At all times, the facility must be operat~d in a mannek 

consistent with good practice for minimizing emissions, and,the 

source must have ~sed best efforts regarding planning, design, 

and operating procedures to meet tpe otherwise applicable 

emission limitation; and I" 

I 

7. The owner or operator's aCtions durin§ startup and 

shutdown periods must be documente~ by properly Signed, 

contemporaneous operating logs, or~ other relevant evidence. , 

, B. GENERAL AFFIRMATIVE DEFENSE PROVISIONS RELATING TO 

STARTUP AND SHUTDOWN 

In addition to the approach oLtlined in Section IlIA) above, 

states may address the problem of ~xcess emissions occurring 

during startup and shutdown periodb through an enforcement 

discretion approach. Further, exc1ept in the case where a single 

source or small group of sources h~as the potential to cause an I 

exceedance of the NAAQS or PSD increments, ,states may also adoPrt 

for their SIPs an affirmative def~nse approach. Using this I ". 
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approach, all ~efiods of ek~eis emissions. arising during startup 

and shutdown must be treated as violations" and the· affirmative 

,,···,· .. ·,,·····'·Oefenseiprbvision'mu·st 'not' be available for claims 'for injuncHve' 

relief, Furthermore, to be approved, such a provision must 

provide that'~he·defetidant has-the burden of proof of. 

demonstrating that: . , . , 

... ,1.' The periods·of excess einissions ·that occurred during. 

startup an~;shdtdo~n·were short and infrequent and could not have 

been prevented through careful planning and design; ., 

2.' The excess emissions 'were not part of a .recurring 

pattern indicative 'of in'adequate .de·sign, 'operation, or 

maintenance; 

3; 'I f the excess emissions' were caused by a bypass (an 

intentional diversion ·of control .equipment), .then the bypass was 

unavoidable to prevent loss of life, personal injury, or severe 

property damage;' 

4. At all times,' the facility'was operated in a manner 

consistent with good practice for minimizing emissions; 

5: ,The' frequency and duration .of operation in' startup or 

shutdown mode was~minimized to the maximum extent practicable; 

6. All possible steps were taken to minimize the impact of 

the excess emissions 'on ambien·t air quality;· 

7. All emission monitoring systems were kept in operation 

if at all possible; 

·8. The owner or operator's actions during the p,eriod of· 

excess emissions were documented by properly signe.d, 

contemporaneous operating logs, or other relevant evidence; and 

9. The owner, or operator properly and promptl'y notifie9 the 

appropriate regulatory authority. 

If excess emissions occur during routine startup or shutdown 

periods due to a malfunction, then those instances should be 

treated as other malfunctions that ~re subject to the ma~function 

provisions of this policy. (Reference Part I above) .. 

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benneI1899a.wpdlAuguSI 11, 1999