@002 STATIO~ARY SOl~CH	 Iitl 002 ~~~ U~~ uhyr~ V~

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
 

WASHINGTON, D.C. 2046D
 

SEP tI1!!! 

M"EMORANDUM 

SUBJECT:	 State Implementation Plans: Policy Regarding E~cess

Emissions During Malfuncticn5, Startup, and Shutdown 

FROM: Steven A. Her~-1IL---'-­ jA~stant Admi' _~, for Enforeement and Compliance 

~:::::n::>Ci'.opo 11_ J IJ _:

Assistant	 Adrnini51F~~\Jo-~dR:diation 

TO:	 Regional ~drninistrator8, Regions I - X 

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

exce9S emissions durin; malfunctions, startup, sh~tdown, and 

maintenance is contained in memoranda from Kathleen Bennett, 

formerly Assistant Administrato~ for Air, Noise a~d Radiation 

dated September 28, 1982 and February 15, 1983. A ~ecent re~iew

of SIPs suggests that several contain provisions that appear to 

be inoon~i3tent with this policy, either becau~e they were 

inadvertently approved after EPA issued the 1982-1983 guidance or 

becaus~ they were part of the SIP at that time and haveneve~

been removed. In order to address these provisions in a 

consi$tent manner, today we are reaffirming and supplementing the 

1982-83 policy. In so doing, we .are taking this opportunity to 

clarify several iS8ues of interpretation that have arisen since 

that ~ime. The attached updated policy will clarify the types of 

exces~ e~issions provisionB states may incorporate into SLPs so 

th~t they can in turn provide greater certainty to the regulated 

community. 

As EPA stated in its 198~ memQra~dum, because excess emission~ might aggravate air quality so as to prevent attainment 

or inter!ere with maintenanee of the ambient air quality 

standards, EPA view~ all excess emissions as Violations of the 

applicable ernis5ion limitation. ~evertheless, EPA recognizes 
STATIO~ARY SOl~CH 09/22/99 WED 16:58 FAX 202 564 0068 UA~ ........ ,. ••t'.... 'f ......... .A..". .....". rn..... VA"""''''":I:UJ.. ~rA VAwr~ u~
 

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that imposition of a penalty for sudden and unavoidable 

malfunctions caused by cir~urnst~nces entirely beyond the control 

of the owner or operator may not ce appropriate. Accordingly, a 

state or E:PA can elCercise its "enforcement discretion" to refrain 

from taking an enforcement action in these circumstancs3. 

The main question of interpretation that ha~ arisen 

regarding the old policy is whether a ~tate may go beyond this 

"enforcement discretion" approach and include in its SIP a 

provision that WOUld, in the context of an enforcement action for 

excess emission!!" excuse a source from penalties if the !Source 

can demonstrate that it rnee~5 certain objective criteria (an 

"affirmative defense"). This policy c:ladfies that states have 

the di$cretion to provide such e defense to actions fo~ penalties 

brought for ExCess emissions that a~ise du~ing certain 

malfunction, startup, and shutdown episodes. 

In the context of malfunctions, EPA recognizes ~ha~ even 

equipment that is prope~ly designed And rnain~ained can sometimes 

fail. At the same time, EPA has a fundamental responsibil~ty

under the Clean Air Act to ensure that SIPs provide for att~inment and maintenance of the national ambient air quality 

standards (~NAAQSNland protection of PSD inCIements. ThUS, EPA 

cannot approve an affi~ative defenBe provision that wou~d

undermine the fundamental requir~ent of attainment and 

mainte~ance of the N~AQS, or any other requirement of the Clean ~ir Act. See sections 110(a) and (1) of the Clean Air Act, 42 

U.S.C. § i410(a) and (1) ,1 Accordingly, an acceptable 

affirmative defense provision may only apply to actio~s for 

penalties, but not to acticns for in;unctive relief. This re~trictiQn insures that both state and federal authorities 

remain able to protect air quality standards and PSD increments. 

rur~hermore, this approach is appropriate only when the 

respective contributions of individual sources to pollutant 

concentrations in ambient air are such that no single source or 

small group of sources haa the potential to cause an exceedance 

of the NAAQS or FSD increments. z Where a single source or small 

lpureuant to Section llO[l}, EP~ may not approve a SIP 

revision if lithe revision would interfere with any applicable 

requirement concerning attainment and reasonable further 

progress, or any other applicable reqUirement of this chapter,lI 

See also § 1~3, 42 U.S.C. § 7S15, anQ the definitions of 

"em.ission limitation" and "emission standard" eontaineci in eM 

§ 302(k), 42 U.S.C. § 7602(kl. 

Z In the case of lead and sulfur dioKide, attainment 

problems usually are caus@d by one or a few sources and an 
IaJ004 

~004

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9roup of sou~ces has the potential to caUSe a~ exceedance of the 

Nk~QS or PSC inerements, EPA believes an af£irrnative defense 

apptoach will not be adequate to protect public health and the 

environment,and the only appropriate means of dealing with 

excess em1ssions during malfunctton, startup, and shutdo~n

episodes i~ through an enforoement discretion approach. 3 

E?A ~s also taxing this opportunity to clarify ~hat it does 

not intend to approve SIP revisions tha~ wo~ld recognize a state 

director's decision to bar EPA's or citizens' ability to enforce 

applicable requirement~. Such an approaeh would be inconsistent 

with the regulatory scheme establisneQ in Title! of the Clean 

Air Act. ~PA is also adding contem~oraneous record keepin9 and notifica~ion cr1te~1o to make its policy regarding these types of 

events consistent with its enforcement approach. 

Finally, EPA is clarifying how excess emissions that occur 

d~ring perioQs of startup and shutdown should be addressed. In 

general, because exoess amissions that occur durin; these periods 

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

EPA recogni2es that, for some source oategories, even the best 

available emi3sions control systems might not be consistently 

effective during startup or shutdown periods. In areas where the 

respective contribu~ion~ of indiVidual sources to pollutant 

concentrations 1n ambient air are such that no single source or 

small group of sources h~s the potential to cause .n exceedance 

o! the NAAQS or PSD inc~ements, these technological lirnitation~

may be a~d~~==ed 10 the underlying standard~ them~elv~~ thtough 

narrowly-tailored SIP revisions that take into account the 

potential impacts on ambient .~r quality caused by the inclusion 

of. these allo~ances. In these instance~, as part of its 

justifieation of the SIP revision~ the state should analyze the 

affirmative defense is not approp~iate. Thi~ situation c~n ~e

Farticularly aggravated where a short-term standard (e.g .. where 

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

in place. A1thou~h this policy is generally applicahle for other 

NAAQS. enforcement Qiscretion is the only appropriate approach 

for ~ealing with excess emissions during startup I shutaown, and 

malfunction in a specif~c area where a singla source or a small gro~p 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. eire .. lS99). the court remanded the PM2.S NAAQS to the 

EPA. The ~gency has not determined whether this policy is 

appropriate for PM2.5 NAAQS. 
f4Ioo~ STATIONARY sotCRCH ilZl ou5 ~." v~ ~A~r~ ~~

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impao~ of the potential worst-case emissions that could occur 

during ~tartup and shutdown. 1 

In addition to this approac~, states may address this p~oblem

through the use of enforcement discretion or they may include a 

genetal affirmative defense provision in their SIP~ for shor~ and 

infrequent startup and shutdown periods along the lines outlined 

in the attachmen~. As mentioned acove l however, in those areas 

~here a single source or small group of sources has the ~otential

to cause an exceedance of the NAAQS or PSD increments, issues 

relating to excess emissions arising during stattup and shu:do~n

may only be addressed through an enforcement disere~ion approach. 

All Regions should review the SIPs tor their states in light 

o! this clarification and take $teps to insure that excess 

emisaions ~rovisions in tnese SIPs are cons1atent with the 

attached guidance. 

Attachment 

4States may account for such emissions by including them in 

their routine rule effectiveness estimates. aule effectiveness 

estimates may be prepa~ed in accordanoe with an EPA policy 

Qocument entitled "Cuidelines fo:t" Estimating and Applying llule 

Effectiveness for ozone/Carbon Monoxide S~ace Implementation Plan 

nase Year Inventories." (EPA-4S2/~-9~-OlO) November 1'92. 
I4l 006 

IlllOOli 

Attachment 

POLICY O~ EXCESS EMISSIONS DURING MALFUNCTIONS, ST~RTUP, AND 

SHUTDOWN 

l:ntroduction 

This policy specifies when and in what manner stgte 

implementation plans (SIPs) may provide for defenses to 

violations caused ~y periods of excess emissions Que to 

rnalfunction~,l $tartup, or shutdown. Generally, since SIFs must 

provide fo~ attainment and maintenance of the national ambient 

air quality standards and the achievement of PSD 1ncr8ments, all 

periods of excess emissicna must be c~n6idered violations. 

Acco~din91y, any provision that allows for an automatic 

exemptionZ for excess emissions is prohibited. 

..1

However, the imposition of a penalty for excess emissions 

during malfunctions caused by circumstances snt1~ely beyond the 

control of the owner or operator may no~ ba appropriate. StAtes 

may, therefore, as an e~erctse of their inherent enfo~cement

discretion, choose not to pen.lize a source that has prod~ced

excess emissions under SUch c~~c~mstances.

!his policy P4o~ideg an alternative approach to enforcement 

disc~etion for areas and pollutant~ where the respective 

contributions of indiVidual sources to pollutant concentrations 

in a~ient air are such that no single source or $~all group of 

sources ha~the potential to cause an exceedance of the NAAQS or 

PSD increments. Whexe a sin91e sou~ce or. sm.ll group of sources 

has the .potential to cause an exceec:1ance of the NMOS or PSD 

~ncremants, as is often the case for eulfur dioxide and lead,3 

EPA believes a?p~oaches other than enforcement discretion are not 

appropriate. In such ca5e3. any eXC8SS emiseions may have a 

significant chance of causing an &xoeedance or '7iolation of the 

applioable standard or PSD incremen~.

'The te~m Bx~ess emission means an ai~ emission level which 

exceeds any applicable emission limitation. Ma'£un~ti2D means a 

sudden and 'unavoidable breaKdown of process or conc~cl equipment. 

%The te~rn automatic exemption means a generally applic~ble

provision in a SIP that woulQ provide that if certain conQitions 

existed during a period of excess emission~. then those 

exceedance5 would not be considered violations. 

'~h~s policy also Qoes not apply for purposes ot PMZ.5 

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

(D.C. eiro., 1999), the coure remanded the PM2.5 NAAQS to the 

EPA. The Agency has nOL Qeeermine~ whether this po1icy is 

appropriate for PM2. 5 NAAQS. . 
~OOi

lQJo07 

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Except where a single source or s~all group of sources has 

the potential to Cause an exceedance of the NAAOS or PSD 

increments, states may include in their SIPs affirmative 

defenses 4 for excess emissions, as long as the SIP estahlishes 

li~itations co~eistent with those set out belo~. If approved 

into a SIP, an affirmative defense would be available to sou=ces 

in an enforcement action seeking penalties brought by the state, 

EPA, O~ citizens. However, a determination by the state not to 

take an enforcement action would not ba~ EPA or citizeq action.~

In addition, in certain limited circumstances, it may be 

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

source-catego~y-specificemission standard a pr,ovi5ion stating 

that the otherwise applicable emission limitations do not apply duri~9 narrowly defined sta~tup and shutQown periods. 

I. AUTOM~TIC EXEMPTIONS AND ENFORCEMENT DISCRETION 

!f a SIP contains a prevision addressing excess emissions, 

it cannot be the ~ype that provides for automatic exemptions. 

Automatic exemptions might aggravate ambient air quality by 

excusing exces~ em1S5ion$ that cause or contribute to a violation 

of an ambient air quality standard. Additional grounds for 

dieapproving a SIP that 1ncludes the automatic e~emption approach 

are discussed in mo~e detail at 42 Fsd. Reg- 56171 (November 8. 

1977) and 42 Fed_ Re9. 21372 (April 21, 1977) _ As B result, EPA 

will not approve any SIP revisions tha~ provide automatic 

exemptions for periods of exoess emissions. 

The bes~ assurance that e~Ce9S e~s~ion~ will not interfere 

with NAAQS attainment, maintenance, or incremen~5 is to aQdre~S

excess emissions through enforcemen~ discretion. This policy 

provides alternative means for addressing excess e~ss~ons of 

c~ite~ia pollutants. However, thi$ policy doe~ ~ot apply where a 

single source or 'mall group of sources has the potential to 

cause an exceedanC8 of the NAAQS or PSD increments. Moreover, 

4The term affirmative defense means, in the context of an 

enforcement proceeding, a response o~ defense p~t forward Py a 

defendant, regarding which the defendant ham the burden of proof, 

and the merits of which are independently and objeotively 

evaluated in a judicial or administrative proceeding. 

~~ecause all periods of excess emissions are violations and 

because af£i~mative defense provisions may not apply in actions 

for injunctive relief, under no circumstances would EPA consider 

periods of excese emis~ions, even if aove~ed by an affi~mative

defense, to be "federally per1n1tted releases" under :SPCRA or 

CERCLA. 
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nothing in this guidance should be construed as requiring $tates 

to include affirmative defense provisions in their SIPs. 

II. ~Fr!RMATIVE DEFENSES FOR MALFUNCTIONS 

EPA can approve a SIP ~evision that ereates an affirmative 

defense to claims for penalties in enfo~cement actions regarding 

excess emissions ca~sed by malfunctions as long a~ tbe defense 

does not apply to SIP provisions that dexive fxom federally 

promulgated pe~formance standards or e~ssion li~its, such as new 

source performance standards (NSPS) and national emissions 

standards for hazardc~8 ai~ pol~utants (NESHAPS).' In addit1on, 

affirmative defenses are not appropriate for areas and pollutants 

where' a single source or small group of sour~es has the potential 

to cause an exceedance of the N~~QS or pso inc~ements.

Further~ore. aff1~at1~e defenses to claims fo~ injunctive relief 

are not allowed. To be approved, an affirmative de!en~e

provision must provide that the defendant has the burden of p~oof

of demon~tratin9 that: 

1. The excess emissions were caused by a sudden, 

unavoidable breakdown of technology, beyond the co~trol of the 

o~ner or operator; 

2. The excess emissions (a) did not stem f~om any aetivity 

er event tha~ could have been fore5een and avoided, or planned 

for, and (b) could not havG been avoided by better operation and 

maintenanee practices; 

3. To the maximum extent p••ct1cable the air pollution 

control equipment or, processes were maintained and operated in a manne~ consistent with good practice for minimizing emissions; 

~l Repairs were made in an expeditious fashion when the 

operator knew or should have known that applicable emission 

limitat10ns ~~re being exceeded. Off-shift labor and overtime 

must ha~e been utili%~d, to the extent practicable, to ensure 

that such repairs were made as expcaitiously as practicable; 

S. The amount and Quration or the excess em1~sion5

(includin9 any bypa~s) were mini~ized to the ma~irnum extent 

practicable auring periods of su~h emissions: 

'To the ex~ent a _tate includes NSPS or NESHAPS in its SiP, 

the standards should not deviate from those that were federally promulgated. Because EPA set these standa~ds t_k~ns into aocount 

teahnolo9ioal limitations. aaditional exemptions Would be 

inappropriate. 

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"t::.:.I vvu 

_. 0 • ._ !ill 009

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6. All possible steps were taken to mi~imi~e the 'impact of 

the excess e~issions on ambient air quality; 

7. All emission monitoring systems Were kept in operation if ~t all possible; 

8. The owner or operator's actions in respo~se to the 

excess emissions ~ere dooum~nted by properly signed, 

cQntemporaneou5 operating logs, or other relevan~ avidence; 

9. The excess emissions were not part of a recurring 

pattern indicative of 1nadequate design, opexation. or 

maintenance: and 

10. Tha owner or opera~or properly and promptly notified 

the appropriate regulatory authority. 

EPA interprets these criteria nar~owly. Only thoBe 

malfunctions that are sudden, unayoidable, and unpredictable in 

nature qualify for the defense. For ex~ple. a single instance 

of a hurs~ pipe that meees the above criteria may qualify under 

an atf1rmatl~e defense. The defense would not be available, 

however, if the facility had a history of similar failures 

because of imp40per design, improper ~aintenance, or poor 

operating practices- Fur~har.more, a source mus~ have taken all 

available measures to compen~ate for and resolve the malfunction. 

If a facility has a bcghouae fire that leads to excess emissions, 

the affirmati~e def_nse would be appropriate only for the period 

of time necessary to modify or cu~tail operations to come into 

co~liance. The fire should not be u~ed to excuse excess 

emissions generatad ~uring an extended periOd of time while the 

operator orders and installs new bags, and relevant SIP language 

must limit applicability of ~he affir.mative defen~e accordingly. 

III. ~XCESS EMISS!O~S DURING STARTUP AND SHUTDOWN 

In general. star~up and shutdown of prOCG$S equip~ent are 

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

fo~ in the p~ann~ng. desiqn, and implementation of operat1ng 

procadure5 for the process and control equipment. Accordingly, 

it is reasonable to e~pect that careful and prUdent planning and 

design will el~minate violation~ of emission limitations during 

such periods. 

A. SOURCE CATEGORY SPECIFIC ROL£S rOR STARTUP AND SHUTDOWN 

For some source eategories, given the ~ypes of control 

technologies available, there may exist short periods of 

emissions during 3tartup and shutdown When, despite be$t efforts 

regar.ding planning, design, and opetating procedures, the 
~UJ.U

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otherwise applicable emission limitation cannot be met. 

~ccordingly, e~cept in the case' where a ~ingle source or small 

g~oup of ~ources has the potential to cause an eXceedance of the 

NAAQS or PSD increments, it may be appropriate, in consultation 

with EPA, to create narrowly-tailored SIP revisions that take 

these technologi~al limitations into account and state that the 

otherwise applicable emissions limitations do not apply during 

narrowly defined startup and shutdown periods. To be approved, 

these revisions should meet the following reqUirements: 

1. The revision must be limited to specific, na~rowlydefined	 soUr~e categories using specific control st~ategies

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

selectiue oatalytio reduction); 

2. Use of the control st~ategy for this source category 

must ~e technically infeasible during startup or shutdown 

periods; 

3. The frequency and ~uration of opera~ion in startup or 

shutdown mOQe must be minimizea to the maximum extent 

practicable; 

4. As part of its, justifi~ation of the SIP rev1sion, the 

stete should analyze the potential worst-case emissions that 

could occur during startup and shutdown; 

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

of ~mia8ions durinq star~up and shutdown on ambi.nt air quality; 

6. At all times, the facility must be operated in a manner consis~ent with geod practice for minimizing em1aaions, and the 

source mUGt have used best efforts regarding planning, des1qn, 

and operating procedure. to meet ~h. otherwise applica~le

emission limitation; and 

7. The owner or operator's actions during startup and 

shutdoWn periods mU3t be documented by properly signed, 

contemporaneous operatinq logs, or other relevant eVidence. 

B.	 GE~ERAL ArFI~MATIVEDErENSE PROVISIONS ~ELATING TO 

STARTUP AND SHUTDOWN 

In addition to the approach outlined in Section II(A) above, 

states may ad~ress the problem of excess emi$5iens occurring 

d~rin9 startup and shutdown periods through an enforcement d~scretion approach. Further, except in the case where a single 

source or small group of ~ourc~s has ~ha potential to cause an 

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

for their SIPs an affirmative defense approach. Using this 
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approach, all periods of eXcess emissions arising during startup 

and shut~own must be t:eated as violations, and the aff{rmativQ 

defen!e provision must not be ava1lable for claims for inj~nctive

relief. rurthe~ore, to be approved, such a provision must 

provide that the defendant has the burden of proof of 

demonstrating that: 

1. The periods of excess emissions that occurred dUking 

startup and shutdown were sho~t and infrequent and could not have 

been prevented through careful planning 4nd de~iqn;

2. The eXcess emissions were not part of a recurr1~g

pattern indicative of inadQquats design, operation, or 

maintenance; 

3. If the excess e~ssion~ were caused by a ~ypass (an 

intentional diver~ion of .control equip~ent), then tha bypas~ was 

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

property damage: 

4. At all times, the facility was opera~ed in a manne~

consistent with good practice for minimizinq emissions; 

5. The frequency and duration of operation in startup o~

shutdown mode was minimized to the maxim~ extent practicable; 

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

the excess emissions on ambient air quality: 

7. ~ll emission monitoring systems Were kept in operation 

if at all possible; 

B. The owner' or operator's aeeions during the period of 

excess emissions wete documented by properly signed, 

contempo;r:aneous operating logs, or other relevant evidence: and 

9. The owner or operator properly and promptly notified the 

appropriate regulatory authority. 

If e~ce6s emissions occur du~in9 routine startup or shutdown 

periods due to a malf~~ction, then those instances should be 

treated as other malfunctions that are suhject to ~he malfunction 

provisions of thi~ policy. (Referenda Part I above).