IT~D.;STATES 

### ENVIRONMENTAL PROTECTION

### AGENCY 

### '&pice of Air Quality PlanningandStandards Research Triangle Park, NorthCarolina 27711 

### JUL 5 1965
,. \'..! 

### MEMORANDUIq SUBJECT: Revised Draft Policy on and Extensions FROM: 

### Darryl D. Tyler, Director Control Programs TO : 

### Directors, 

### Air Division Regions I-X The attached draft policy for handling changes to sources which have FSD permits and extensions of these permits is a revision of the November 19, 1984, draft policy distributed to the Regions for con~mcnt. This revised policy incorporates your comments on that draft. There are two major revisions to the November 19, 1384, package: (1) the secti'on dealing with extensions for phased construction projects has beei? altered to provide a better explanation of the manner inwhich extensions for dependent and independent mu1ti-phased projects are :ia;?dlzi ;I?(! 

### the ratiorale for a d~stincticn between the tkm types of projects; and (2) a new section devoted exclusively to permits for steam cjsnzrators subject to 40 CFR Part 60 (I'ISPS) when the permit involves a r~llii~g 30-day average emission limit 

### for S02. There have been other changes to clarify the text and respond to the comments we received, but those changes are relatively minor compared to the two revisiohs discussed above. Inparticular, 

### if you feel that the section dealing with the rolling 30-day avarage NSPS for S+ 

### should be treated as a separate policy, please indicate this inyour comments. We do notwant to hold up the entire policy inorder to resolve this recent addition. We also intend to hold a discussion on this topic at the Mid Pines NSR Workshop; please be prepared to take this opportunity to discuss your concerns. We would like to receive a11your coinments on this latest draft by July 19. Unless substantial adverse comment is received, rewill begin review of this package for formal 

### EPA policy adoption. 

### Itshould be noted that Section 

### VIIof the policy, Protection of Short-term Amoient Standards, includes new requirements for an agency which has issued PSD permits that do not specify short-term SO2 emissions 1 imits to adequately protect ambient air increments and standards. Insuch cases,... , 

### (1) 

### the sectfon dealing with extensions for phased cons'tructioh " - . .
. . 

### 'projects has $2217

### altered to provide a better explanation of the manner in which extensions for dependent and independent multi-phased projects

. .- 

### ?rehaxiled and 

### tile rationale for a distincticn between, the two types of 

### projects; and 

# . , . . I

. ,... , .. ! 

### (2) a new section devoted'exclusivelv to nermitscfor steam ~snerators subject'to 40 CFR 

### Par en the"perm;

### t 30-day average emissi 02.

. 

### There have been other'changas to clarify the text and respond to the comments we 

### received, but 

### those changes are'relatively' + 

### the two rev5si20t5sdiscussad above. .\ t' 

### In partic~ilar, if you feel that the section dealing with the rolling 30-day aq2raje NSPS for SO? should be treated as a separate policy, please indicate this in your comments. We do not want to hold 

### up the entire policy in order to resolve this recent addition. kle also intend to hold a discussion on this topic atthe Mid Pines NSR Workshop; please be prepared to take 

### this opportunity to discuss your concerns. We would like to receive all your comments on this latestdraftby July 19. 

### Unless substantial adverse comment isreceived, we will begin review of 

### this package for formal EPA 

### policy adoption. Itshould be noted that Section VIIof,the. policy, protection of Short-term Ambisnt Standards, includes new requirements for an agency which has issued PSD permits thatdo not specify short-term SO2 emissions limits
. 

### to adequately protect ambient air increments and standards. In such cases,


## EPA7APC013296

2.

### the proposed policy requires the agency to revise the perrnit 

### by adding liinits which 

### will provide such protectian. For all other cases, the policy presuines that the applicant is the party requesting a change. Ifyou have any questions, please contactGary NcCutcl?en, 

### (FTS 

### 629-5591). Thanks again for your assistance indeveloping this important policy, particularly the efforts of Roger Pfaff, Region 

### IV.

cc: B. Bankoff 

### G. Ernison 

### B. Pedersen 

### E. Reich P. Wyckoff

### 6/85 DRAFT PSD Permit 

### Modifications: Policy Statement on Changes to a Source, a Permit Application, or an Issued Permit and on Extensions to Co~struction Schedules AGENCY: 

### Environmental ProtectionAgency ACTION: Proposed policy statement
SUMMARY: For several years both the Environmental ProtectionAgency (EPA) and various States have issued permits for the prevention.of significant deterioration (PSD) of air quality to proposed new and modified major stationary sources. Some of the permits require revisions to reflect changes inconstruction or operating plans, including construction schedules.
Ir? 

### other cases, changes inplans have been proposed by applicants prior to permit issuance, or after EPA 

### has determined the source, as oriyinally proposed, isexempt from PSD review. No formal policy has been issued wh.ich addresses how such changes are to be handled. Consequently, a source owper proposii?gcha~?ges to a 

### source has no guidelines to determine what requirements must be 

### meet. Si

### nce no provisions are coctained inthe Act for modifying PSD permits already issued, a11 the requirements of PartCand a repeat of the permitting process appear to be necessary for changes insources not reflected inthe originally issued permit inorder to prevent obvious circumvention. That is, a new permitmust be obtained if 

### a proposed change would involve: (1) 

### a major modification; 

### (2) a difference inconstruction or design from what
was originally planned, when an increase inemissions or ambient impact would result; (3) a fundamental a1teration of an emissions unitor source; or 

### (4) a difference inapplicability, such as a source no longer being .exempt from PSD review. Today's policy proposes to provide a new and less cumbersome route by which changes can be accommodated while ensuring the equivalent environmental protection required under the Act. Indoing so, 

### it 

### eXtends the Alabama Power concept of

### - de minimis to include changes whichare so small interms of impacts that such changes could be excluded from the full rigors of permit review. The policy statement provides guidance for 

### (1) re-examining EPA-granted permit exemptions, 

### (2) revising any EPA-issued PSD permit or PSD application, 

### iccludicg those administered by States which have since obtained jurisdiction for PSD, and 

### (3) the development of State and local agency permit revision regulations or policies. EPA eccourages States to adopt similar policy statements concerning source changes and the processing of State-issued permits which need revision or extension and solici 

### ts comment as towhether such procedures should be required by 40 

### CFR Part

### 51. Today's policy staterii?rt proposes to distirgiiish between sources which have be~un operation acd those which have cot indetermining the type of procedures used wh?r d proposed change will require permit revisions. 

### A p~:-i;:itrevision for 

### a source already operaticg generally car be treated like any cthsr emissiors ircrezse or decrease at 8 major source ucirg est.-ulicned

. . procedsres. For a source notyetoperating, EPA proposes to group the racge of possible cha~yes to a PSD permit into three categories, based on their potential significance to the program: (1) those which can be expedited without detailed review (administrative changes); 

### (2) those which can be processed as permit revisions after appropriate analysis (minor and significant charges); and (3) those which should be treated through issua~ce of a new PSD permit (fundamectal changes). The required analysis for permit revisions typically would involve reconsideration of the basic decisions involved in the issuance of the original permitfor the units that would be affected by .the proposed change. Sepacate sections on the criteria for extending the 18-month commencement of construction dead1ine applicable to a11 PSD permits and on handling permit revisions resulting from the use of a 30-day rolling average SO2 new source performance standard (NSPS) are also provided.DATES: This policy statement is effective as interim guidance upon publication. The period for initial comment on the proposal closes on [date 30 days from the date this notice appears inthe FEDERAL RESISTER]. 

### A public hearing on the proposal 

### will be held on 

## , 1985, at 10:OO a.m., in 

## ,Denver, Colorado 80295. ADDRESSES: Comments should be sent intriplicate if possible to: Central Docket Section (LE-131), U

### .S. Environmental ProtectionAgency, 401 M St, S.W., Washington, D.C. 10460. Attn: Docket No. A-83-40. DOCKET: EPA has established docket number A-83-40 for this action. This docket isan organized and complete fileof all significant information subiiiitwd to or otherwise considered by EPA. The docket is available for public inspection and copying between 8:00 a.m. and 4:OD p.m., Mocday through Friday, 

### a t EPA's Central Docket Sectioa. A reasocable

.- ice nay be charged for copying.

,.. FgRTiiiR !NQi!IRIES: For. ?~:rtheri?for!mation, contact Gary IJlcCutchea,

. . New Source Review Sectioc (MD-15), Environmental Protection Agency, Research Triaagle Park, North Carolina 27711. SUPPLEMENTAL INFORMATION: 

### I. BACKGROUND A policy is needed to maintain the basic integrity of the PSD permitting process required by the Clean 

### Air Act when requests are received to revise, add to, or delete conditioas on issued permits or information contained in
a complete application. 

### A rigorous preconstruction review for PSD would ultimately not be effective ifsources could readily obtain subsequent .relaxations to their permi.t conditions under a lax policy for permit revisions.

For example, the Act clearly intends state-of-the-art application of best available control technology (BACT) by PSD sources, buta lax policy forsubsequent proposed changes could undercut the environmental protection offered by the original BACT determinations. Nhen EPA revised its PSD regulations inAugust 

### 1980, theAgency deferred the development of guidance governing its PSD "permit modification" process, 

### i .e., the procedures by which proposed changes to a source, application or permit would be handled. Since then, the Regions and States have handled requests for such changes on a case-by-case basis. These involve a broad variety of redeterminations of exemptions from perinit requirements and permit changes, both minor and important, arising from sources which are already operating as well as those on which construction has notyet commenced. TWis lhas catiiral

### ly l?d to a variety of d?cisiors across the country and, hence, creates confusion and 

### irefficiency inthe permitticg process for 

### iFA, irdustry, ard the States. A natiorwide policy is recessary to assist 211 parties ir deal-irgwith PSD source changes acd the need for PSD permit

.:.
. . ... rev:s<o?s in.2cai.sistent ma?%r. !c addition, scch a policy 

### \./ill .serve to-
, . establish a firm policy framework which resolves questions of legal risk wher a judgment ismade that new permits are not required. Current policy requires that a new permit be obtained ifa proposed change constitutes: 

### (1) a major ~nodification;

### (2) a difference inconstruction
or design from what was originally planned, when an increase inemissions or ambient impact would result; 

### (3) a fundamental a1teration of an emissions unit
or source; or (4) a difference inapplicability, such as a source no longer being exempt from PSD review. Today's policy proposes to provide a new and,less cumbersome route by which changes can be accommodated while ensuring .equivalent environmental protection. Indoing so, itextends tne Alabama Power concept of de minimis to include changes which are so small interms 

### - - of impacts that such changes could be excluded from the full rigors of processing.

### Due 

### to the similarity between major and minor "source modification" and "permit modification," itis important to establish a terminology which will not be confused with existing PSD terms and which can be used consistently and precisely to describe the situations and actions regarding this policy. Therefore, the term "permi

### t modification" will not be used. Instead, the following terms are used to describe this policy. 

### A "change" refers to the proposed or actual a1teration of an application, perini

### t, or source, or some combination of the three. 

### An application for a proposed change initiates Agency action if the application is complete. When the proposed change has actually been made, the altered source, permit, ,,plicatior is referred to as "changed" or "revised." Changes are classified 3:- a3-- 

### accordicy to the effect they would have on the reviewing agency's assessment of ti?. 

### sovrce. Ir orOer of ircreasing importance, changes are considered:



# . ,Adinir:istraI-$ve. 

### :,r admii?istrativecharge involves no increase ir 

### --
+ .. . . 

### ..ej.,.y;ere!n<sjicrs

### or jmpact; .ard-nofurdai~ertal charge ic-.ei thcr thesource -' . -, ., 

### or one of the emission units atthat source. Application or permit revisions may be necessary, but 

### additional review or analysis would not normally be required; examples are typographical and company name changes. One exception is the extension of commence construction dates, which may require a limited additional review consisting of 

### BACT reanalysis and public participation. 2. 

### Minor. Minor changes require revisions to permit applications or issued permi

### ts and a certair amount of additional review and analysis, but 

### do not constitute either a fundamental or significant change. Emissions or impacts increase as a result of minor changes, 

### but not above the significance 1

eve1

# . 3. Sigcificant. Significant changes are changes where one or more pollutant emission increases exceed the applicable significance level(s) but which do not constitute a fundamental change. Major modificationreview level is triggered unless the affected source is notyetoperating; significant char.ges at preoperating sources are considered application or permit revisions. 

### 4. ~"ndamental. A fundamental change isso basic innature (size or type of source or emissions unit), regardless of the net emissions or impact differences, that the changed source or emissions unit isconsidered a new source or emissior.8 unitand thus triggers a totally new permit review. A fundamental change could even result inan emissions decrease but still require the owner or operator to obtain a new permit. Examples include proposing a kiln inplace of a dryer and proposing a 

### 500 TPY unit inplace of a 

### :Ci3 TPY urit. The effect of a chapye depecds inpart on the status of a project. Project status

### rnilsstopes are: 

### I. ixein;?ted i-om PS3 review

,. .

. .

## . . * . 

### 2.

. Pc.e~-i?rs irvctioc ?SD :err:; 

### t appl-ica.tion Sl~bmi tted .., " .. , .. 

### 3. Preconstructiot: PSD permit issued, butsource is notoperational (also, the applicabi

### ii ty of new PSD rules is affected by whether constructior. of the source has commenced) 

### 4. Precor.struction PSD permit issued and source inoperation The results of various combinations of changes and source status are suminarized 

### inTable 

### 1. A procedure for determining which result is applicable to a specific source isdiagramed inFigure 1. Note that both Table 

### 1 and Figure 

### 1car. only su~nmarizethis policy; more detailed informatior. appears in the text. 11. AGENCY JURISDICTION a Today's policy covers all PSD applicability decisior.~ and all PSD permits originally issued by EPA. This includes those PSD applicability decisions and permits which are still under Agency jurisdiction, as wellas the applicability decisions and permits issued by EPA which subsequently
come under State jurisdictior? as a part of PSD program delegation or SIP approval. The Agency intends that today's guidance also be used as a model for States developing their own permit revision processes for PSD, nonattainment
area (PartD of the Clear! 

### Air Act) and other new source review purposes. EPA be1ieves that regulation$ governing proposed changes to sources, permits
or applications are needed as a legal a1ternative to having to issue a new permit for a11 except certain administrative changes. €PA solicits comment
or the need for separate 40 CFR Part

### 51 regulations requiring State adoption of a siinildr policy to ersure the credibility of State PSD programs, as well
as 

### ti!? reed to extend this policy to include nonattainment area inajor sources 

### ar:d major. modificatio~s. As a inin'imum, EPA believes that state-of-the-art 3,s t ach;eva>.le cortro! t$chcoiogy (SACT) should be guaranteed by ary State reecsi!!? t<or

### ~i PSC ap;:i.icatiors and permits.

. , .. ,.. 

### IiI. CLASSIFICATION AND REVIEW OF CHANGES There are two primary factors to consider indetermininy the scope of review to be imposed upon a source inresponse to a proposed change. The firstof these involves the significance of the proposed change; the rnore significant the change, the more involved the review 

### will be. Four levels of change have been identified (administrative, minor, significant, and f~indaniental) 

### , leading to the same number of (but not always corresponding) levels of review stringency: amendment, revision, major modification and
new permit. 

### A second factor, stage of source development (whether the
source has been issued a permit, whether the source is operating and, in
certain cases, whether corstruction has commenced) 

## , iscri tical 

### in determining what action is required and whether any of the original increment allocation (for.particulatematter and sulfur dioxide) ispreserved. For reasonsexplained below, various changes by a source that is notyetoperating can reasonably be treated ina more stringert manner than would the same activity by a source already inoperation. 

### (A) stage of Source Development EPA proposes to classify some PSD-related source changes differently depending on whether the change is for a source that has already begun the operation authorized inits PSD permit. This difference intreatment between sources notyetoperating and those already doing so is based on several factors: (1) a project initsearlier phases ismuch more flexible than one already operating; (2) the company's commitment to the project prior to operation is less clear and its position regarding further changes
ar a piact which is notyet ir operation differs frcm that of most existing soaris: ard 

### (3) 

### ti?? test of i+ihi.ti?er a Source can operate and produce a .?rcr?!,~ct 

### b.irder the or$g'ral corstructior pla?s 

### ?l ;m;nates a great mary



### ..

## .

. -...:. . , . pi>ji~:.li ii.e.8.of. obvious r.3:-cu:r.verticn of the regviatioi!s. Treat'ng ar.

. . operating source as esse~tially having completed the permitting process eliminates the burden of uncertainty on the company of constantly having to evaluate proposed projects in lightof changes made years ago. Today's policy acknowledges these factors by typically imposing a less rigorous process for proposed chacges atoperating PSD sources. EPA solicits comment
or the reasor!ableness of this approach and on whether other events such as co:nmence!nect or completior of constructior should have some greater stacding ir. a final policy. 

### it should be noted that commencement of construction already confers an exempt ("grandfather") status to a source not only 

### ir! 

### -CFRParts 51, 52, and 

### 60, 9ut also inthis proposed policy when determining whether newly-issued rules are applicable (see below). 1. Pre-operational Sources. An application for a change to an application or permit for a source notyet inoperation would generallyprompt reanalysis of the proposed project as if the original application had been submitted 

### ir that form. However, some changes would be corsidered sufficiently unimportant that they could be treated as application or permit amerdments; these are termed admiristrative changes. Other changes would be important enough to prompt the need for a revised or new application
or permit, and could require additional review actions. These various levels of change are discussed indetail inthe nextsection. For application and permit changes requested prior to operation, EPA is proposing that the changes be handled as part of the initially permitted project, rather than as new projects. Th@ Agercy is concerned that changes
t'idt are irdjviduaily smal 

### I would be accumulated such that 

### a cumulative sigrificart change would rotbe given the full review that such a charge siiould receive. Thus, ever a - de m$nimis increase ir a poi1utar.t cdr be 

### s:;'iJect tii PS3 r?v;ew 

### .if t?at poilutact siouid be significart wher' added to

. .. . ... :prev:i.ous irc.reases. (Th:is..i,s.further explair!eii, below tunr!er 

### (;j)2. Revisiocs..)

. .. .- , . In order for EPA to treat such a change as a new project, and not as part of the already permitted project, the applicantwould be required to inake a demonstration that the two projects are physically independent and were considered to be separate projects for planning purposes. If the reviewing agency concurs that the new project is a separate project, the change can thec be treated as such. These criteria are identical to those used for judging separatioa of projects a1ready constructed (see below). The only difference is that EPA initially presumes that a change atthe siteof a noroperating source is not a rew project. 2. PSD Sources Alreacy inOperation. Applications for changes which would affect sources which have already been issued 

### PSD permits and been placed inoperation have generally been treated the same as applications to charge any existing major stationary source. That is, 

### if the cha~ge is 

## EPWAPCO1 

## 3306significant, itconstitutes a major inodification, as defined at

### 40 CFR Part

### 52.21, and a complete PSD review is required; if the change is not significant, itdoes notconstitute a major modification and no PSD review applies. Under today's policy, changes 

### will instead be processed inthe
manner described 

### in the next section. The only exception to the approach described below arises frorn the need to avoid circumvention of the regulations: 

### if the proposed change snould reasonably have beer! partof the initial project rather than a separate project, itshould be evaluated as part of a new total source impact rather than as a separate action. At times, such proposed changes take the form cf "separate" sources or even projects involving more than
one source. However, if the reviewing agency judyes that such sources or p'ojects are part of the I prgject covered in a previous PSD application, 

### ti-,? 

### ::har$es ihoilld ibe treated {derticaily to ciiarges for sources rwh'ci? have

. . -. e: ~&~,~,p
.



### gp~.:.sii or.. 1,hi.s I??!!&t be deter;nined $y the .rev?;i.+.i?g .a<;efi~y

. .... , . 

### :..
or 

### a case-by-case basis, tauing into accouct wheth2r the proposal represents charges at the source which are physically independent of the origina! project, and whether the applicant can provide documentation to show that planning of the second projectoccurred after the planning for the first project. Thus, ifa PSD-permi tted boiler has been constructed, and the
owner then applies for a 

### -- de minimis increase in

### SO2 emissions from the boiler, wiiich in the judgment of the review agency should have been a part of the original permit applica tion, the requested change cannot be treated
as 

### a new application (and therefore be exempt'from review because itis

### - de .minimis). 

### Itwill instead,be subject to each PSD review element within the permit revision process as described below. Conversely, if the applicant applies for a new processing unitto be used ina completely separate

### production area of a chemical plant, this application can be treated as a
new project and exempted from review, if 

### - de minimis. (B) 

### Levels of Review 1. 

### Amendment. Changes to a permit or application are classified as amendments if they are administrative in nature and result in no increase ireither the emissions or the air quality impact of a PSD source. In addition, neither the nature nor the size of the source or emissions uni

### t
car. be altered to the extent that the change would be considered fundamental. Amendments may be quickly processed without any major reevaluation of the decisions originally made in permitting the source. Examples of the type of cnacye which would often be treated as an aiilerdment include coinpany came
or operator chanyes, requiren1er.t~for more frequent monitoring or reporting 5y 

### the perinittee, correctior of typographical errors, emissioc decreases a1 

### ttioi!gn such decreases, 

### to be used irretticg or tradirg, must 2e 

### carefull,y

..,.. , 

### -dnc:i!ner.teri) an.! mi-or 

### b;a?d+rgc:l.arificat.iofis. It

### shouid be coteci 

### that8

... . . .. . , .. .. 

### fundamental change (seebelow) may also result in no increase in emissions
or impact, but

### cannot be treated as an amendment. The lack of emissions and impact increases for an amendment results in little or no review. Proposed amendments (which are nearly always administrative changes) to applications and permits do not require any reanalysis of the basic review originally submitted and need not be subject to piiblic participation requirements as a gereral rule. However, the Agency emphasizes that there may be instances where changes which are normally administrative may be sufficiently importact that the reviewing authority determines that review
.or public participation is.necessary, e.g., a change of ownership of a proposed source to a company which has been involved in highly controversial projects or has received public attention as a result of the manner in which' other air pollution sources owned by this company were operated.One administrative change which always receives some level of review is the extension of commence construction dates. Such changes cons

### titute amendinents butmu8t be reviewed to ensure state-of-the-art BACT; inaddition, itis usuai

### ly appropriate to seek public comment on the proposed extension, since other potential new sources may be affected. 

### A more detailed discussion of this type 'of change appears inSection VIbelow. 

### 2. Revision. The term revision encompasses the review level required for the large majority of minor and significant changes atall preoperational
sources and atexisting (operating) major stationary sources which do not qualify as "major modifications," as dafined by the PSD regulations, or as fardaine:?ial changes. iievisio~s icclude, in the case of operating sources, :nost charges involving copstructior! or chacges in the inethod of operation of a source, cd co::irol equipmect, that do 

### -- not produce a cet s'igrificart
.,;Ti- ...,,, s~ors 

# . itccrease; 2 r? t sigrifica-t eaissiors ircrease resultirg froin 

### a ;i::ys,icai .c!?zryecr ::Rar?e 

### ifi. themethod of operation.ata? operati!:y source

. -.. . , . usually corstitutes a major modification as defined in the rules and is processed as such. Itshould be noted that there isa distinction between (a) modifications (as defined in the PSD rules) which are notsubject to NSR, and 

### (b) changes (whether requested or necessary) to a permit or permit application. A change which does not result ina significant net increase iremissions is cot considered a "major modification" and is not subject to PSD; liowever, the chanye (nay require (or the owner may request) a revision of the source permit (or application). Insuch cases, the reviewing agency may consider some level of reanalysis and review necessary before revising thepermit or accepting ar.application revision. For example, a source may want to change a solvent used inone of its processes, with no increase in emissions, but the permit specifies the solvent to be used. Before revising' the permit to allow use of the new solvent, the reviewing agency may decide

### to repeat public comment if the new solvent ismore odorous or toxic than the current solvent, repeat the impact analysis if the new sol vent ismore reactive or toxic than the current solvent, or revise some other component of the exi; ting analysis. Despite the possibility of a revised analysis, nonsignificant emission increases do not constitute the type and degree of review-to which major modifications are subject. In many cases, itis anticipated that little or
no revised analyses will be required of nonsignificant emissions increases. 

### On the other hand, changes to permit (or application) parameters which the review agency considered important enough to include on the permi

### t (or rely u?on in the applicdtion) should certaicly be subject to review before those parameters are revised.


## ~. Ths 

### term ri.v:s!or also ercompasses tne level of review of iiiost 

### cacdidate a:;?.lcat!oc ard pzrmi

### t ciiti~ges 

### wilich are praposed atsources v4n;ch are ?catocwit:!:res;)ec>:to. cons-triicti,ofi,approved 

### ic their PS!? 

### permi.t,

. .. 

### The ocly exceptiocs are those changes which are administrative, or which
are so great that they require a totally new PSD review (fundamental changes). Once a change is classified as requiring the revision level of review, 

# <t is screened to determine which elements of PSD review now apply and to what extent. 

### A revision will firstrequire a screening analysis to determine whethsr existiny analyses addressing the PSD requirements are sti11 

### accurate
o: whether there is a ceed for revised analyses. Iqajor components of the
cew source review irclude 

### BACT, ambient impact analysis, monitoring requirements, additional impacts analysis, Class 

### I area protection, and public participation. -A 

### full description and explanation of these review components is contained in the August 7, 

### 1980 FEDERAL 

### REGISTER (45 

### FR 52676). 

### Depending upon what change is proposed, this screening may be very simple, as in the case of a very.smal1 increase in the size of an emissions unit, or very involved, as

### in the case of the addition or replacement of a new uni

### t ata preoperational
source. The proposed change must be examined not only to see if any existing analyses should be revised, but

### also to see if any new analyses should be performed. The criteria for requiring additional review elements will be whether the original new source or major modification application underwent all of the review which would have applied had the application been submitted in its revised form originally. In addition, any new requirements added to the PSD regulations since the time that the original permit was issued also could apply, unless construction had commenced so as to qualify for an exernpt'or (as djscussed below). If 

### there is ro circuiiivertion of the permit requireiaerts, the r-evisior rev?e\vwouid focus on only that portion of the sc,j:.si. im!riediate!y i?v~lv?.d i

### n the proposed change, rather than all of tL?j? i 

### s 

### i)?ev.io:i~lyr;)~; 

### .?~*ied.

. i-!:? 

### e):aii;?iii. 

### .is a pro,oos?c! c4?3?ge ;priorto permit 

### issuance to.add il

### !!nit

. .. , ,.. , 

### emitti?g 

### 15 tons per year of S32 to ar application for a source which originally provided for 100 tons per year of particulatematter and 35 

### tons per year of SO2. This would constitute a minor change. Since the change is combined with the original application, both the new uni

### t and the already permitted units must undergo each PSD review element for S02. This is because the original permitted level of SO7 

### - was 

### - de minimis, thereby exempting SO2 froin rev';ew, but 

### the total new level of SO2 is significant (35

### TPY 

### and 15 

### TPY together exceed the 40 

### TPY threshold). However, the original application date is used in a1locating increment for the original 35 

### TPY SO2 emissions .leve1 unless circumventior.of the SO2 review had been intended. As another exainple, suppose a permit for a new PSD source allows 60 tons per year of SO2 emissions and the source was not required to gather preconstruction monitoring data because i

### t created a 

### - de minimis ambientimpact. The source owner wishes to lower the stack which emits S02, making total SO2 impact significant. The source owner would therefore be required to conduct a new modeling analysis and gather representative preconstruction monitoring data before the cnange could be approved. In processing a revision, whether for a minor change or a significant change, the reviewing authority must follow the same public participatior! procedures noted in40 CFR 52.21(q) for the processing of preconstruction 

### PS3 permits. EPA believes that the reconsideration of the conditions and review of an existiny permit undergoing revision should receive no less
an opportunity for public involvement than did the original permit application. This ir?cludes pub1ic notification by newspaper advertisement inthe area 

### of the source. The notice would contain inforination regarding the agency's prelirninary deterniria

### tior, tile expected ambient impact of the proposed chdrg?, the 3C-day oiip9rturity for r!ri tten cornrnect, 21:d an opporturity for 

### a ;ub!ic tear.ing..

... . . A proposed change qualifying as a revision, rather than as a new permit, receives certair. befief 

### i ts. As mentioned previously, a revision
can be exempted from any new PSD requirements that were added between the time of the original permit issuance and the submission of the proposed change if the source had commenced construction prior to the adoption of the new PSD requirement. "Comnience construction" is defined in terms of tile owner or operator having dl1 the necessary preconstruction approvals
or permits and either having (1) begun, or caused to begin, a continuous program of actual on-site construction of the source, to be completed .within a reasonable time, pr (2) entered into binding agreements or contractual ob'ligations, which cannot be cancelled or modified without substantial loss to the owner or operator, to undertake a program of actual construction of the source to be comaleted withir! a reasonabletime. The purpose of subjecting revisions to new requirements for sources not havicg commenced construction is to remove the potential benefit 

### a source might obtain by submitting a questionable application to reserve increment or avoid new PSD provisions. Another major advantage a source gains by qualifying for a revision, rather than having to obtain a new permit, is that the source retains the ircrement rights afforded by the original application or permit. Neither
cew permits nor fundamental changes to an original proposal (which by definition change the very character or nature of a source) preserve the original increment a1locatioc, because that a1location was for 

### a specific type and size of source ata specific location. An allocation is not autoriiaticaliy corferred to, for example, a cement plant which is proposed in

.. ..,, t,c:.h~ :.3cs::r.1e.d. i;?:yr]::i: t$,at

### wig;cally

### a1located, toay'5:pol4.cy .i!o:i!d 

### a11o!~

. tne adaitional :rcreniect consumptior: only when increment is available after prior complete appiicatiors have been processed acd only atthe concurreme of the State inwhich the source would locate or is located. If new increment corsumption beyond the significance amounts iden

### tified inthe 

### 1978 preamble (excluding Class 

### I areas where any new impacts must be authorized by the Federal Land Manager) would result atany point, such increment consumption m!;s t also be authorized by the State inwhich the source would locate or is located. An especially significant issue arises from situations inwhich there .is competition for the available air resource: other permit applications ard changes are pending such that the ambient ceiling imposed by the 

### NAAQS or increment would prevent the granting of all of the applications. In such circumstances, EPA would take a firstcornelfirst served approach

### to allocating the growth rights, subject to State approval. This means that the original emissions growth rights would be preserved but 

### that the reinaining growth rights would be awarded to intervening applicants filing applications prior to the filing of the proposed change. When 

### EPA is implementing this policy, itwill recognize the rights of complete PSD applications filed with States which have 

### the responsibility under their
own PSD program for future permit applicants. Any State taking jurisdiction of EPA-issued permi ts may develop a1ternatives to firstcome/firs

### t served allocation of air resources to which 

### EPA would generally defer; of course,
no such a1ternative system can allow an increment violation to resuit. 3. Major Modification. Operating units which propose changes that constitute a "major modification," within the meaning of the NSR regulations
are subject to those requirements. 

### Generally, this review is equivalent to the requiremerts for a Pew source (seebelow), but 

### the review is conducted orly for the nodificatioc, :ot for the ertire existing source. The term "major modification" is deficed as "any physical change in or change in the method of operation 

# ... that would result in a net significant emissions increase..

# .." Physical changes are, in general, readily identifiable, but 

### changes in the method of operation are often more subtle. The latter includes such activities as removal or significant a1teration of pollution control equipment. For a source notyet operating, however, proposals which would normally be considered major modifications would generally under this policy be treated as an application or permit revision (see above). 

### 4. New Permit. Some changes are sufficiently important such that a separate new application or permit is required, rather than a revision to the existing application or permit. These are of two types. First, a change to an application or a permitted source which affects the fundamental nature of the source triggers the need for a new permit. 

### A general guidetowhether the fbndamental nature of a source is being changed iswhether the proposed changes would result ineither a different2-digit SIC Code for the source or a large increase insize. However, the reviewing authority must use good judgment and make this decision on a case-by-case basis. A new application or permit is required for fundamental changes because the proposed change would be of such major importance to source operation that the basic permitting process should be repeated, with no .iccreinent rights reserved. For example, a chacge from a dryer to a kiln rnay affect a review such that differentemissions control or product recovery operatiocs would be found to be feasible for the kilnwhere they
were rot for tne dryer ucder the original acalysis. Since itis often inappropr.iate to apply SIC codes to portions of sources, this procedure carrot easily be used ~i?ec the iproposed action



## . . W1Ji6afFect ocly 2 part uF ar existiry sourcc. The rev;ewicy authority

F
. rr

J , d ~liereforc ciecide 3:: d case-by-case basis whether the fi:nddmenc.al cature of the permitted portioc of the source is being changed. 

### SIC codes could be used as a guide to do this. For example, if a new boiler is placned or permitted ata kraftpulp mi11, acd the applicantwishes to construct a lime kiln icstead of a boiler, itisclear that the fundamental nature of the unit (the boiler) isbeing changed, even though the source (the kraft pulp inill) is cot; the lime kilnwould require 

### a new permit. Fundamental changes ic the size of a permitted emissions unit or source are those changes which iccrease the fixed capital cost of the emissions unitor source by greater than 50 percent. This could often require more than a 

### 50 percent increase insource or emissions unitsize, since cost per production unit usually decreases as the size of the unit increases. 

### A decision to review a change as a new permit application would generally entail the same data development as would the original permitapplication, although the review would focus on the proposed changes. In many instances, data from the original permit application could be used to expedite the new perniit review process. Additional data would often be required for the new or changed units and all units affected by them. 

### If the new or changed units affect the original BACT, air quality, and modeling analyses, these analyses would need to be revised accordingly. As ~oted above, one area where the processing of certain significant ard all fundamental changes may differ greatly from that of many significant acd all minor chanyes concerns the awarding of new increment rights: sources or emissions units involved inapplication and permit revisions (which assumes rofundanental change) retair! their origical increme~t riyhts during the revision process. 

### Ir! cortrast, a change that is processed as a new permit :nust compete for available air resources behind acy complete aiipiications



## ., i; 

### led before tile cciiip;tzte 

### ap;?licatior! for the chacge is filed. It is importar!t 

### t- cote thdt, wh: !e the perm.; t as prev:ously issued ertities the criginal project design to be built, the permitdoes not award equivalent ificrement riyhts to the source for ary substantial shift inconfiguration, type, or size of ur!its that itmight wish to construct. If there has been much growth inan area or if the area is heavily icdustrialized, air quality may have deteriorated so as to be near the ceiling imposed by the incremerts or NAAQS. Ir! such a case, a new source permit may cot be issuahle. Consequently, either the one-year deadline for processing a complete application

### wi11 be control1icy (EPA mustdisapprove
a permit if insufficiect increment is available within a one-year timetable) or, if the original permit has already been issued, the 18-month deadline for commenciny constructior! (assuming no extension) 

### wi11 force the source attempting to change 

### its PSD permit to finish 

### its original construction plans or to withdraw its proposed change and not construct ata11.Figure 

### 1 o"t1ines the process that a reviewing agency can follow in classifying an application for a change. EPA also offers Table 1 inorder to convey summarized guidance on which of the above described levels of review should be applied to various types of permit changes. Table 1 lists
a wide range of ways inwhich a source might be changed and indicates the Agency's proposed conclusions on which forms of review would apply. It should be noted that both Figure 

### 1 and Table 1 are presented for purposes of 

### !1lustration; other types of changes may occur and, inaddition, special circumstances may arise which prompt the review authority to address a charge differently. The Agency solicits comments regarding other types of everts which sllould be ircluded on the listor on the way that the listed itens are classified.

' iIACUiviYiRTiON i? cietericti?ati?r by a rs'diiew agercy thdt a proposed charge cotst'itutes circc::i:!.e"ticr resv: 

### ts.ai!t.?:n;;Mcz!

### ly .in 2 require;nert that a ?el4 sfrn:i 

### 2

. . . . applicatior: be filed. Tne app1.icar.t would be urable to preserve a!?y of the ircrement a1located to the original permit. A1though circumvention has been discussed inmore detail elsewhere, the concept of circumvention within the framework of changes to 

### a source presects additional complexitief;. An example of circumvention would be the proposed addition of a 15-tonsper-year 

### SO2 enlissions urit to a permit for a source originally proposed to en.; t 150 TPY particulate%atter ard 

### 35 TPY 

### S02. The reviewirg agency then d;scovers that a 50 TPY 

### SO2 unit had been planned for that source from the beginning, but that the applicant had attempted to avoid SO2 PSD review (including BACT) by applyicg intwo stages. Insuch a case, the original permit isvalid only for the source exactly as specified. If the applicant wants to change the source, a new permit application must be filed. None of the original increment allocation is preserved; the "complete application"

### date for the source would be the date the proposed change application was considered complete. This policy is intended to discourage the submission of deliberately incomplete or misleading applications through loss of any increment a1location that resulted from such actions. However, EPA 

### would still intend,
even in cases of circumvention, that any portior! of the original application and review which are still applicable be retained, and that subsequent actions concentrate on the changes to the source that resul

### t in a need for additional revjew. 

### V. INCREMENT ALLOCATION AND 

### PRESERVATION Currently, 

### EPA a1locates increment on a first-come, first-served basis, using the date a coiriplete application was subrnitted to determine an applicant's place in lire. The allocated ircrement is assigned to the specific source (or 

### emiss::or:s u::i 

### t) arid locatioc described ir tile pernii

### t and ap(11 ication;

; 

## . + 

### car~ot be 

### used Sy 

### the apijl?cartfor another source, even if the second

,.. . . . . S~!.J?CF 

### .is121

### aroed 2t 

### the s..?-ie 

### locatioo, nor.can i

### t te vs?d ~CC 

### the same.type

. . , . 

### of source ata different location. For example, assume a permi

### t has been issued for a cement plaot at Location 

### A, wi th 

### an anticipated Class I1 (plantboundary) 24-hour total suspended particulate (TSP) impact of 40 micrograms per cubic ~neter (ug/m3) and a nearby Class I 

### 24-hour TSP impact of 2 ug/m3. The increments reserved for the cement plart are the 

### 2 and 41) ug/m3 Class I 

### and 

### I1 impacts. If the oviner decfdes irstead to constract an asphalt plant atLocation 

### A, the ircrements assigned to the cement plant are not "preserved" for use by the asphalt plant. The owner must submit a new application for the asphalt plant, receive a new date of submittal of a complete application, and try again for an increment allocatiol?. 

### (In fact, without today's policy even minor changes to the cement plant could result in loss of the allotted

### increment, since the increment use is assigned to the source ar!d location exactly as specified in the permit and application.) Similarly, if the cemect plafit owner decides that location B 

### would be
a better place to construct than locatior!

### A, the increment allocated to the cement plant atlocation 

### A is not preserved for use atlocation B. 

### The
owner inust submit a new application for location B 

### and this new date of subinittal of a complete application isused to establish the first-come, first-served -incremertallocatior!. In addition, current policy does not provide any increment allocation for proposed sources which atfirstare exempt from PSD revjew but

### become subject to PSD 

### review ata later date due to a proposed char!ye. For example,
assume a 

### 1isted Source A 

### (major at100 

### TPY) is estiinated to eini

### t 85 TPY of 

### SO2. Tne owcsr submits ar iippl

### icati3c to th? 

### reviewii?~ ageccy, is toid tlia

### t tile source is exemgt from 

### PSD 

### review, acci proceeds to 0bta.i~ a;

### 1 the ',"S,..

... -4.:. a,.,. ,, 

### .dry, L~ 

### i?d:il SCJ

### I 2ger.cy

### p~;ii;i 

### ts ax z-oninence consti-ucvi:31'1.; A ... . . 

### this poirt, the oi.rr?er discovers that S02 emissions from this source will be 115 

### TPY S02 rathe? thar! 

### 85 TPY. 

### Assuming that there is no indication of attempted circumvention, the source under currect policy must sti1

### 1 reapply and, even though already ucder construct'ior!, the new applicatior!date is used to a1locate increment. If another application for a large SO2 source had beer! subinitted between the firstar!d second Source 

### A applicatiocs, Source 

### A may be denied a perini

### t despite the constructior! costs already committed to the project. Today's policy, ir! contrast, provides in certain
cases for the "preservation" of incremefit that 

### had previously been allocated to a source if (1) 

### the proposed change is not fundamental, and (2) there
was no intent to circumvent new source review provisions. Preservation of ircrement refers to the retention by a review agency of the original complete application f

### iling date in determining allocation

### of increment on a first-come, first-served basis. In other words, this policy specifies that for administrative, minor, and significant changes, the original complete application submittal date is used to a1locate increment. However, the preserved incremefit is based on no more than the original emission rates ar?d ambient impacts. If the revised emission rates or ambient impacts increase, only the "original" portions of the total pew rates and impacts are preserved; the increases are allocated on the basis of the date a co~nplete applicatioc for the proposed change was submitted. If the revision results in emission rates or impacts less than the original levels, the remaining portions of the original rates or impacts are no locyer preserved: tnjs is because this policy is not intecded to provide trad5rg or cettirg credits to a proposed source. The orly intent is to
reserve a quaiifyir?g source's piace in lice for ircrenient allocatin?. As ar. exa;:ipl~, assuxe Saiirc? 

### 6 subraitted ar origiral coinplete application

, , for.

### 2.75.TPY

### 55i:onJa-i\i~&ry. 2(.1.,,.?986i,

### Or iiugus

### t 15,

### ,1336,before a i:t?rni 

### t has been issued, Source 3 

### files a complete application for a chaaye which would increase SO2 emissions by 55 

### TPY, to a total 330 

### TPY 

### S02. 

### On a first-come, first-served basis, increment from Source 

### B is allocated using the following dates: January 20, 1986 

# - 275 

### TPY SO2 

### Aligus

### t 15, 1986 

### - 55 TPY 

### SO2 Note that the source's place ir lice for the original incremect is based on tne origical applicatioc date, hut 

### that subsequent increases in emissions
are allocated based on the date the application for the increase was filed. Source B, 

### under today's policy, would not be competing for all 330 

### TPY 

### SO2 einissions 

### on the basis of an August 15, 1986, increment allocation date as would have beer! the case under currentpolicy. Instead, Source B 

### competesfor only the 

### 55'TPY SO* additional increment or? the basis of the later August 

### 15, 1986, applicatior filing date. Sources which had previously been exempted from PSD review present a particularly difficultsituation. These nonmajor sources consume increment but, urlike major sources, are not allocated increment. Today's policy, however, a1lows increment a1location preservation for sources which, as a resultof a proposed admi~istrative, minor, or sigrificant (but not a furdamental) charge, would become major as long as no circumvention was irtended. Such sources viould have increme~t allocated for the original ernissiors rates on the basis of the original (exemption) complete application :!ate ard the ddditioc?al ei;iissior?s rates on the oasis of the proposed cha~?ge conplete applicatior! d~te.iiius, the origi~al source, even though exempted from PS; 

### rr'viii~~ $5elirjj;?;f? 

### f.)? soine de9ree of ircre!ner.t preservat.ior!.



## . . T35s ;ioliiy .15 int:?!?!!ec; t, dpp.ly to sources vih<ch have rotyet completed

.... .. . . c.ol:j trur.cj$fie, 

### .Tr..??,$Si> rui.e;.. provj

### de.tnat?xex]; te.-?..',' \ scuries ~o subject to FSO do rot becoin? subject to PSD until their ernissior.~ exceed the threshold 

### I imits acd they ther propose a major modification (with ore exceptior:


### a modification to a minor source which would initself qualify as a major
source 

### will result 

### ir PSD review), but this does rotaddress proposed charges to a source prior to completion of that source. Sirce ircrement preservatior using firstcome, firstserved, re1ies to a great extect 

### or the date of submission of the origi~al application, tnis is a particularly importartdate to document. Owrers and operators who feel that a source is exempt from PSD review are nevertheless encouraged to promptly submit complete applications for the State permit or for the record, even if they have already been informed verbally that a source is exempt, because the submissior! date establishes i~crement a1location priorities. Without a clearly documented original complete application date, this policy

### wuld be difficil

### t to apply. 

### In cases where the date a complete original application was filed cannot be determined, 

### EPA will use the date construction is commenced. VI. 

### EXTENSION OF 

### 18-MONTH COMMENCEMENT 

### OF CONSTRUCTION 

### DEADLINE One permit revision topic that deserves special attention is extension of the 18-month commencement of construction dead1ine. The subject regulation, 40 CFR 

### 52.21(r)(2), states that "Approval to construct becomes invalid if constructior- is rot commenced within 18months after receipt of such approval, if construction is discontinued for a period of 18months or more, or if
construction is not completed within a reasonable time. The Administrator iaay extend the 18-niorth period upoo a satisfactory showing that an extension isjustified. This provisioi: does not apply to the time period between coxtr~ictio~ of 

### ti-:e apprsvsd phases of 

### a phased constructiofi projsct; each 

### !p'.is? ??US 

### t c%imerc:! copst.r:~ctior! i.ii 

### thi~: 18niorths of the projeczed and ?DE~~VC.(I 

### c3in1i::!ncexer: 

### r.d?

### t.?*" : ., . . , , 

### Itis important to rote that the Clean Air Act and 40 CFR 

### Part 

### 51 regulations do not expressly ir-clude the 18-month dead'line. Therefore, those States that have takei: over the 

### PSD program through SIP development
are not required to have the particular 18-month deadline in question. However, those States to whom the PSD program has been delegated are required to implement the 18-mooth deadline, since a delegate State is implementing the Federal reyulatioas. Often itis difficult 

### to determine in the preconstruction phase how all aspects of the construction plan will develop. Many of the permits issued in the earlier part of the PSD program arematuricg as projects. Corsequently

## , the EPA 

### has received several industry requests for various adjustments to their permits and construction schedules. These requests
are usually based upon chacges in the economy, weather, or consumer consumptioninareas such as energy. EPA is responding to this need by interpreting the r e g u l a

### tion and proposing the policy articulated here for reviewing extensioc requests. Effective implementation of these provisions is especialiy important inview of the prospects for economic growth. The showing which a source must make inorder to receive a permit extension has been a longstanding problem. Various approaches have been advocated, ranging from a stringent standard, such as impossibility in the legai sense, to such lesser showings as economic impracticality. Each of those approaches presented varying degrees of subjectivity and certain difficulties of factual aralysis. Today's policy avoids those difficulties by providirg extersions to virtually ail good faith applicatiors for extensiors to which the affected States do notobject. 

### A good faith effort;iiust include
a certificatior tliat tne co!iipary currertiy pians to comi?lerce co?structior oy 

### a specific date tbat usualiy should fa1

### l withir the requested extension

. .,, , . ,. . . 

## . . .i,:..,",".

%, .but experd. .rurti-;2;-j(!tc;'",., future 

### if i

### r ;s wjti,i;i.w'hijt.

. . . . .,. Ltli the review agency co,?siders a reasonable period of time. The i~tent of this is to discourage situations where a source may not plan to actually
commence construction for a number of years butcortinues to tie up increment ard consequently prevent growth which could occur immediately. Previous decisiors often a11 owed a source making the threshold showing of justification of ar extecsior to proceed 

### without flirther aralysis. There are persuasive reasors for reopenirg certain portions of the permit review, such as BACT, when a permit isexterded. As described below, today's policy expressly provides for this further analysis. Providing extensions more readily but requiring more substantive review of those extensions preserts a reasorable comproinise that simp1ifies the policy while assuring important ervironmental protection.The Clean 

### Air Act requires review of new sources to be timely. This is especially important for key elements of review such as BACT determinations and ambient impact assessments. Consequently, there must be 1 imitations on the period granted inwhich a source can construct without an updated review. In particular, BACT isan independent requirement under the Act ard the Act contemplates that the BACT be current for the period inwhich the source's cocstruction isactually commenced. Similarly, ambient air quality can chacge considerably, rendering inadequate an assessment performed atan earlier time. This policy generally outlines a method which addresses
coocerns about the consistency of extension requirements across the country, wnilecoriiplying with the Act's requirement that certain PSD determinations be timely. It is emphasized that timely requests for extensions or other noj:fjcatiocs are ci~e respcrsibi

### ii ty of the source. A permit i4ii1 a"toil:atically cease to exist 

### i? a request for extension is not received
re."s-,expiratio.r ?&:?.-. 

### I!: the'.case 

### of. .a:later request, 

### a 

### new permit

. ., ..,,,. .~ application must be filed. Today's policy proposes that candidate perinit extecsion8 must meet the following tests for substance and processing inorder to be issued: 

### A. BACT Review. EPA believes that inmany cases the original BACT deterinination would stiI1 qualify as BACT if itwere reviewed. This is especially the case sirce cocsideration during a BACT reevaluation is given to the costs that would be iccurred ic changing plans and equipment purchases 

### if a differett techooloyy were employed. These costs and time delays may be prohibitive if construction had a1ready commenced and the
source was notdesigned to accommodate new state-of-the-art control technology, but EPA notes that there 

### will also be cases inwhich a1teration of construction plans isfeasible. This could well be true of long-term, mu1ti-unit projects for which major improvements inBACT have occurred and the expanded constructiontime frame has proven conducive to such project a1terations. However, EPA 

### will require a BACT reevaluation on all extension requests to the extent of reviewing EPA's BACTiLAER Clearinghouse. The original SACT determination
can be assumed to remain appropriate, even if construction has notcommenced, 

### ifno significant state-of-the-art advancement inBACT isnoted from EPA's BACTILAER Clearinghouse data or from the subsequent public comment period, and rotmore than fiveyears has elapsed from the time of the original BACT determinatioc. B. Additional PSO Review Requirements. Other aspects of PSD review such as ircrement rights acd air quality impacts 

### will be assumed to remain valia urless adverse coniiiiects are received from affected State(s), Federal Laro ibiacagers 

### , or other irteres ted parties duriry the public comnert period, sfrice subseqr~er:"igrowth ic tile area snould have cocsidered tile impacts of the per;:i:tted soiirce. Adverse soi;iii1e?ts, if rot reasocably addressed by the

,.... .. . . . ...-.pp

### !iczct,.w; 

### 1.1.typically.trigger tne ceed for a c:)cfe.re?ce ai::or.,: 

### EPA, the. applicart, the affected State(8)

## , and other itterested parties such as Federal Land Managers. The cocference may be combined 

### with the public participation requirements for extensions. The State is responsible for ersuring that interim source growth inthe area of the perinittrd source has rotcaused sufficient degradation of air quality to the extect that operation of the soiirce requestirg the extension would cause or contribute to increment
or NAAQSexceedarces; ceitiler extersiors of issued permits nor issuacce of additioral permits isallowed when they would cause or contribute to such exceedances. If the State icadvertently fails in this regard, 

### itis responsible for remedying any subsequent violations by obtaining sufficient emissions reductions 

### ir the area. The State is also responsible for indicating whether an extension consumes a11 remaining increment, thereby prohibiting issuance of permits to other possible sources in the area. A source willnot be subject 

## tb any other aspects of PSD review beyond those mentioned above. 

### C. Duration of Extension. EPA's regulations do not state the maximum length of extension which can be granted. In practice, EPA's Regional Offices have used 

### 18 months as the norm and, incertain instances

## , have a1lowed 1

onger extensions. Due to concerns of growth rights and public participation, EPA will presumptively 1imit extensions to durations of 

### 18 months, or less, \.if th renerial possible. This allows industry the possibility of mu1tiple extensions if necessary but ensures that the impacted State(s) and public have control of their air resource and growth rights and that state-of-the

### a?t BACT 

### viii

### I be eiiiploynd. 9. Public Comment. The Clear 

### Air Act particularly emphasizes the 'inpar tarce nf pub1ic coinriii?rlor ndtters affect!rg air resource consumption.

-. i:i?rc?for?, EpA iv.i11 

### e the sane public participation procedures for



### :n: rimum 30-day public comment period. E. Extension of Later 

### Urits of Phased Mu1ti-Unit Projects. Phased mu1ti-unit projects are considered either dependent or independent by EPA. In a footrote in the preamble to the 

### 1978 firal PSD regulations 

### (43 FR 

### 26388), EPA defined the difference between these types of phased projects: "The dependence of faci

### 1ities 

### within a source 

### wi11 be determined or! an individual basis. 

### Two or more facilities 

### will generally be considered deperdent if the corstruction of one biould necess

### itate the construction of the other facility(ies) atthe same site inorder to complete a given project or provide a given type (not level of) service. 

### A kraft pulp 

### mi11 is an example of a source 

### with dependent facilities, whereas a three-boiler power plant is a typical example of a source with major 

### independent faci1

### ities

# ."
The purpose of this approach was to differertiate between those phased projects which would be "grandfathered" (i.e., not subjected to new PSD rules) and those which would not. Dependent phased projects were considered fullycommitted as soon as construction began, so all of the dependent facilities
were accorded the same status; 

### ifconstruction on the firstphase of a dependent phased project commenced by an applicable grandfather date, then all of the dependent facilities were considered grandfathered even ifconstruction of those phases of the project had notyetcommenced. Conversely, each phase of an independent phased construction project had to individually commence cocstruction by the gra~dfather date to be grandfathered. This approach to phased projects was upheld inAlabama Power Co. v. Costle. The 1978 preamble also states that EPA does not generally intend to limitthe time for cor?struction of phased projects, butdoes intend to :.?quire commencement of corstruction of the first phase 

### within 18 monihs of perrnit approval and of subsequent phases witliii? 18 inonths of the date aj~rsveci :I? th? i;zrnii t. Breaks 

### ir copstruct.ior, as 

### wi t!i single-phase prsji.cts, cari:ot exceed 

### 18 morths. These require1ner:ts apGear in40 CFR

. .

# ..- ..pirt52.,21(r)(2), !~ri~:e ..i-.~te!!sioi\s. of-thet'ize per5od betwpec. c3nstrci::tis:r
, .. . of different phases cf phased construction projects are not allowed. The UtilitiesAir Regulatory Group (UARG) has petitioned EPA to delete the portion of the regulation 1imiting extensions of permitted construction ic7.tervalsbetween phases atphased construction projects. 

### Since the regulation could be i~terpreted as a1lowirg for extefision of the construction commencement deadline only for the firstphase of independert, mu1ti-unit projects, and
s

### irce mos1 uti1 

### itjconstruction projects are phased irdependect mu1ti-unit projects, UARG is concerted that the reyulations prohibit extensions for 1

ater phases of these uti1

### i ty independent mu1ti-phase projects. Inresponse, EPA provides the following clarifications. First, itis EPA policy that both dependert and independent phased projects may obtain a single comprehensive PSD permit for all phases of the project. 

### A single permit offers an applicant the advantages of reduced paperwork and assurancethat the entire project (rather than only a portion of it) ispermitted. Since comprehensive permits apply to projects which are often large and complex, such permits should specify atleast two 

### i tems that are not needed inpermi

### ts for single-phase projects. These 

### iteins are: (i) Which BACT determinations will be reassessed prior to commencement of construction, and (ii) The date by which later phases (but not necessarily the initial phase) of tile project must commer?ce construction. BACT review (and redeterminations of BACT 

### as appropriate) is required by 40 CFR 52.21(j) (4) atthe latest reasonable time which occurs no later than 

### Id mootns prior to comcnercement of construction of each independent phase of a project, so irclusior 

### ir a permit of the BACT determinatiors which 

### wi11 be reassessed is rota requ;r?mert for beirg able to coriduct sucn a reassessment. i-i3:,1ever, the irclvslor of this inforinatior 

### ir the perinit proviries the

w-er,c.pe.?a.tor 

### ,.. the i.rs.pfr",or,:and the pub1i.c advance notice:of thi. .icter,.t

. .. . .. ,.. of the review agercy to conduct such a reassessnent. The commence cocstruction dates 

### ir the permit cannot be exteqded using the mechanism embodied in

### 40 CFR 52.21(r) (2)

## , but this does notmean that such dates are unchangeable. In fact, those dates 

### - can be changed, but not by the granting of extensions. Since these dates are 

### a part of the perrnit, changes to the dates require a permit change, which 

### will usually be considered
an adolir.istrative change (albeit ore which rormally should irclude BACT review ard public participation). The "projected and approved commencement date" referred to in40 CFR 52.21(r)(2) is the date which appears in the permit,
a date which can be changed by revising the permit. The procedure for changing commerce construction dates which are embodied ina permit is the same procedure used for any other permit change, as outlined intoday's policy. The initial phase commence construction date isextendable using


### 31 

## EPA7APCO1 

## 3328the 40 CFR ~art'52.21(4)(2)procedure urless that date isalso embodied in the permit. Wher embodied ir! a permit, ever the 

### iri tial phase comineoce cor!struction date can be changed only through a permit charge. The above policy cor!cernir?g the initial phase commence corstructior date may appear to corflictwith 40 CFR 52.21(r,)(2); itdoes not. The irtentof 40 CFR 52.21(r)(2) is to establish an automatic 18-month expiration date for permits, with provisions for exterding the expiratior! date or? a caseby-case basis. For phased projects with a sirgle comprehersive permit, 

### EPA presumed that commercemer!t dates for each phase of the project, except the iri tial phase commercemert date, would be incorporated into the permit. Thzrefore, 

### iritia1 phase cominerceiaer t ciate charges would be hard;ed 

### with


### a @OCF!?52.21(r) (2) extersior, and subsequert phase commencernett dates :,:~ui d "i i16i?diec: ti?ro,yi-i jit?r!nit charges. This ack~oviedgesar!d jreserves 

### tihe validity arid 

### Icga!. ty .,f the corditiors specified 

### ir a permit.

.. . .. . 11: =or.some rezso?,,-c_:~i!!. 3s 

### a lorg ?lac"?>> lead time on a complex project, the iri tial phase coclmerceinert date is lor?ger thar 18 niorths but
sti1

### 1 within a reasorable period of time (e.g., 2 years and 

### 6 morths), the review agercy may specify the iritial phase commer!cement date inthe permit, keepirg irinir!d that tile source isgrarted 

### 18 morths beyord this date to actually commence corstructior. A1terratively, the review agency may specify tile permit expiratjar date ir the permit. The expiratior date simply ircludes the iti tial 18-morth grace period; itis determired by addirg 18 inorths to the commerce corstructior date ard avoids the corfusior! that could result wher! dealicg with the commerce corstructior! date alore. The specified date
ir? the permit takes precedent over the "automatic" 18-month expiratior! based
or the permit issuaoce date, but ir! doirg so rerders the permit ineligible for the 18-mor?th extensior process described ir! 40 CFK 52.21(r)(2); a permit change is required to charge a commencement (or expiration) date that appearsina permit. 

# here is an exception to this: 

### if the date specified inthe permit for the initial phase of a project is simply the expiration date of the permit (the commence construction date plus the 18-month grace period), then that date is assumed to be inthe permit for information purposes, does not make the source ineligible for 

### 40 CFR 

### 52.21(4) (21) extecsions, and does not need to be changed to grant extensions of the expiration date. For some projects, the commence construction dates for each phase may have beer. ircluded ir the application or other materials, butmay not appear iethe permit. Insuch cases, the commencement dates for each phase are those dates which the review agency used inevaluating the impact the
source would have. Nearly always these 

### will be the dates submitted by the applicart in tne applicatior, ard these coininencemeet dates are chacyed by fc;llowitg today's ?oiicy or cliargicy applicatiors ard permits. As a part of ary such chacge, r?v:rw agsrcies sho~ild cot orly revise the dates in the 

### icatior,, .-but. als:? irc1;d.e the i;x.tended..c-ommer,remert or exp4ration.date i: a revised permit. Independent phased mu1ti-ucit projects have the option of havicg separate permits for each phase; dependent phased projects do not have this optior, because all phases of a dependent project must be completed for that

. project to operate as intended. Separate permits for each phase of an irdependert phased project are treated for processing purposes as if each permit was for a separate faci1

### ity, 

### with icdeperdert commencement dates, ?ACT determinations

## , enforcement actions, etc. Separate permits may increase paperwork, but inreturn provide an applicant with the optior?of proceeding with planring on a project one phase ata time. The concept of "separate" permits versus a sfngle comprehecsive permit ismore 

### a matter of the manner inwhich the phases are treated than the physical manner inwhich the permit is issued. 

### A single comprehensivepermit, for example, could consist of a number of permits for various emission units and phases of the project, with possibly a general permit to address conditions common to a1

### 1 the project facilities. Conversely, "separate" permits for an independent phased project may physically consist of a "single" permit which nevertheless treats each phase separately. Of course, EPA would presume that single and mu1tiple permits were what they appeared to be unless there actually existed some clear basis for treating a sirgle permit as a set of separate permits, and vice versa. The reason for distinguishing between dependent and independent phased projects 1 ies in the applicabi1 

### ity determinations when new or revised PSD rules becoilie effective after corstruction comiiierces oi: the ici tial phase, but before constructiol! coinmerces on the lastphase. All phases of dependent lp?ased projects are grdr!afatilered [not subject to tile new or revised PSD rgles if carstructior ;ii? the p?~j~?it (USUS! ly the first phase) had coiniiierced

L*



### ;,.$k,e-.eff,?ctiv? 

### d.?:?. of the rsie cfiarge andrc, irialidi ty ii,pses jr! . . corstructior had occtirred]. Incontrast, each phase 

### of an icdependent pnased cocstructiori projectmust individually cominerce construction by the prescribed grandfather date(s); any phases which had commenced construction would rotbe subject to the rew rules. Since the concerr expressed by UARG appears to be addressed toward 

### mu1ti-ucit power plarts which may have beer permitted as depecdect, rather tnar irde~erdert, mu1tiphased projects, today's policy offers irdeperdent phased project applicacts ar opportunity to convert (or otherwise obtain ackrowledgement from the review agency of such change inproject classificztion) a deperdent mu1tipnased project permit for that project into independent mu1tiphased project perinits with full preservation of the increment allocated by the original permit, as long as no increment or NAAQS exceedances would result. This conversion (but pot any simultaneous or subsequent requests

### for other actions, such as extensions) would be carried out without additional ?SO 

### review requirements, such as review of BACT, 

### although such conversion does not abrogate any other authority either 

### EPA or other review agencies have to reasssess permi

### t analyses. 

### In particular, this conversion would rot allow circumvention of the BACT 

### review prior to construction of each irdependent phase which is required in 40 CFR 

### 52.21(j)(4). UAKG 

### also expressed concern regarding the time taken by review agencies to decide whether to grart construction date extensions, citing a case where
an applicant fe1

### t forced to initiate construction simply to protect the validity of the permit because no response to the request for an extension hat1 

### beer, received. Aitliough the new policy described above of providing extersions to virtually all good faith applications should resolve this problei~, 

### EPA shares the coyerr of UARG 

### that such "forced coostructio~?" be pre\i?rted. Therefor?, todiy's pol<cywill also ircorporate the fo:lowirg ap;)rcac;: ir hacdlins 

### sach 

### :'iqi;ej.ts (1) A 

### source has ar, obliyatior to provide sufficient time for an agency to review requests for extersion of a conlinencement of construction date. Therefore, such requests (i ncluding adequate documentation) should be submitted to the review agency atleast six months prior to the date on which the permi

### t would become invalid (

### the scheduled commencement of construction date plus 18morths). (2) EPA 

### will inake every effort to respord to sucli requests within three months of the date the request for an extension is submitted. (3) If 

### a request was submitted in accordance with paragraph 

### (1)above, ard EPA has not responded within the three-month ti~ne period indicated .;r paragraph (2) above, the? the permit invalidation date will be considered extended automatically in such a manner that an applicant will always have atleast three months between the date on which 

### EPA does respond and therew permit invalidation date. The three months provides the applicant time to either commence cocstruction or take other action. This policy does not apply if the applicantdoes notmeet the obiigation expressed iaparagraph (1); ir such cases, there is no automatic extension of the invalidation date. For example, assume a permit was issued for a large project with an anticipated commencement of construction date of 2/1/86. The date the perm; t would become invalid (unless construction had commenced) is 18 inonths after this date: 8/1/87. On 1/30/86, the source applies for an 18-month
extersion, meeting the six-months-in-advance source obligation. If EPA agrees to tile extecsior, then the extension is for 18 months from eithe[. the :avalidatior? date (8/1/87) or the date EPA respoaded, whichever is late:.. If EPA &sapcraves ai?y extersion, the irvai?datiordate is either 

### 7 0:. three niorths 1 the date of iPA's resgorse, wh5chever is later,

, 

# .'

. 

### ?RGTECT!Qh OF S){CRT-TE?i{ #,MSiENT STAIID#,XU$

, . . , 1t has been the practice of many review ageccies to presume that any einissiors 1imit compr-ises a "not-to-be-exceeded" co~tinuous emissions 1imit, whether that limitis ircluded ia the permit (e.g., "SO2 emissior?s shall not exceed 875 pounds per hour"), referenced in the permit specifically (e.g., 

# - "this source issubject to Regulation 6, Section IV.A.Z.b.(ii), for fossil fuel-fired steam generators"), or referenced gererally (e.g., "I;? addition 

# - to the specific corditions coctained hereir, source issubject to a1

### I applicable rules al?d regulations.. 

### ."). That this assumption iswidely held isevident in the number of cases where the review agency (and applicant)
uses an emissions 

### limitto determine 3-hour and 24-hour amb'ient air impacts, butdoes cotspecify the averaging time for the emissions limit. The New Source Perfor~narce Stardards (NSPS) have reinforced this assumption of 

### a continuous emissions 

### 1imit through the prescribed reference test methods,

### which generally average three or more samples taken over periods of time ranging from one to three hours. Thus, use of NSPS limits or NSPS test methods has been considered sufficient indication of the intent of the review agency to establish not-to-be-exceeded continuous emissions 

### 1imits. A 

### divergence between the NSPS emissio~s rate averaging time for fossil fuel-fired steam generating units and the PSD emissio~s rate averaging time requ<rementsfor these same units is affecting this assumed interrelationship. Protection of the PSD SO2 increments requires einission limits with averaging times no longer than the averaging times for the increment. Thus. compliance 

### w?th a 3-hour SO2 increment requires an emissions limit averaging time of 3 iiours or less. For exanple, assume that a continuous emissions limit is 2stablished for a source ata level that would result in a 3-hour ambient
.> 

### :.,+act :- r 

### almost iderticdi to tile ambient impact ircrement ailowed; the emissioc! 

### 1

### 'mi t pre\lenis ":i:.akU e:niss 

### io.? rates ttiat coiild result irexceedarces .he iccrener.t.. 

### An emissio-s 1 initwith a 6-,.hoiiraveragirg- 

### time wo!il 

### c

... , 

### rotrecessarily provide this protection; a 3-hour "peak" could be offset by a 3-hour "low" to meet the 6-hour average emission limit, but tile ambient impact during the 3-hour "peak" would exceed the 3-hour incremen

### t. On October 21, 

### 1983 (48 FR 

### 48960), EPA proposed new SO2 compliance, emissions measurement, and reporting requirements for sources subject to rieiri Source Performance Stardards (NSPS) under 40 

### CFR 

### 60 Subpart

### D (fossil fuel-fired steam gererators larger than 250 million btu 

### per hour heat input). This proposal would require Sc)2cornpliance testing agains

### t the existing numerical NSPS 1;mits of 1.2 and 0.8 pounds SO2 per million btu 

### for coal ard oil, respectively, but requires compliance demonstrations on a continuous basis through the use of continuous emission monitors (CEM) 

### or fuel sulfur aralysis (FSA). Sulfur dioxSde emissions would be calculated on a rolling 30-day average basis instead of a short-term (approximately 3-hour) stack

### test. A1 though a rolling 30-day average NSPS (SubpartDa) had been promulgated
on Juae 11, 

### 1979, for new electric utility boilers (44 FR 

### 33580), the October 21, 1983, action would apply after the fact to nearly 500 operating Subpart D 

### units for which the ir.itial permits relied to some degree on the presumption that compliance with the NSPS would be achieved on a continuous short-term (3-hour and 24-hour) basis rather than on a continuous 30-day rolling average basis. Many reviewing agencies have determined air quality 

### <mi)~ts by modelirg the NSPS 

### limit (1.2 or 0.8 pound SO2 per million btu) as the maximuin short-term emissior! rate for most Subpart D 

### and many Subpart Da sources, but did not specify such short-term analyses or continuous compliance p:.ocedurcs 'ic 

### t!ieir perm; t 

### cordi

### tfons. Ar? 

### ernissior levei which averages 1.2 pound S02 per millior t~tu over a iisriod of 30 

### clays car oi: a short-term basis be nigher Char that limit as



## . . 1x9as 

### ths 

### 30-day s:nI;s:o?s zverage atctr Seiow 1.2 

### pounds SO2 per millio~ btu.


### r p . . 

### sx:!>ip! 5, .].Q 

### .jr!.ys a:.. 

### 1,3 

### pr::ci.nr. S3- % 2: 

### mi 

### 1-1(on.Sti; 3rd 23 days ,of !;0 pou~ds . 

### per million btu wjl

### I average 1.1 pounds S02 per mil'lion btu and ineet the 30-day average NSPS, but will exceed 

### 1.2 pounds SO2 per million btu 

### for 10 of the 30 days. This is not intended to imply that a rolling 30-day average makes possible extremely large variations in emissions rates; itdoes not. The 10 days of 1.3 

### pounds SO2 per million btu, for example, had to also be cornpersated for by the 20 days preceediny th.is higher 10-day rate, sirce this is a rollifig average. Hoiever, policy is required to avoid confusion by both sources acd review agencies regarding what short-term and long-term emission limits must be met by sources affected by these NSPS revisions. Since the most important role of 

### PSD permits 

### is to prevent significant deterioration, EPA's policy regarding perinits affected by this and utlier NSPS revisions is based on the effect of these actions on the ambient air. The NSPS action was based on both technical and cost co~siderations, but the 38 

## EPA7APc013335revisions of perhits for any PSD sources, whether related to NSPS revisions
or cot, are based or! PSD goals and air quality considerations. 

### A. Subpart D Sources EPA's policy regarding PSD permits for Subpart 

### D sources affected by the October 21, 1983, NSPS proposed revision is this: 

### (1) If there are any SO2 emissioc limits (e.g., pounds SO2 per hour, poucds SO2 per megawatt, etc.) inthe permit, these liinitations represent 

### BACT acd inust be met by the source unless and until such limits are altered by a permit change usicg the procedures specified intoday's policy. Any permit emission 

### limitisconsidered a limitwhich must be complied with continuously 

### inl less specified otherwise. (2) PSD permit einission avzraging tiines are co~?siderecl short-term averaGes, ever. for the Subpart O 

### NS?S 1imits, as loiig as itcar! reasorably be presumed that at tii+ t'me of permit issiiance the emissions limits were

crsidered-,550~ 

### t-ternern;ss;or 1im.its.(e..g, 

## , by useof such 1 

### iiait..in.:nodel; 3-hour or 24-hour ambient impacts). That lirnit remains a short-terii! 

### limit (regardless of the regulatory revisions to the NSPS) unless and unt! 

### 1 the permit ischanged to specifically indicate otherwise. Infact, a short-term emission 1i~ni t may not always be included as part of the permit (a1though good permit processicg practices encourage the inclusion of 

### - all applicable conditions and 

### 1imitatiors); the 1imits used indemonstration of short-term amb<ei!t air impacts comprise correspocding short-term emissions 

### 1imits. (3) If the ocly SO2 emissio~ limits associated with the permit are specifically stated to be long-term (longer than the 3-hour and 24-hour averaging times) and no short-term SO2 ambient air impacts were determil?ed, the PSD permit is incomplete, the 3-hour and 24-hour increments and NAAQS must be protected, and an analysis is needed to provide such assurance. In this case, the review agency (without waiting for a requestfrom the 3 9 

## EPA7APCO13336source) must reassess short-term inipacts for all sources on the basis of maximum articipated short-term emissions. If the legal authority exists for a review agency to initiate revision of ar incomplete PSD permit, the ageccy should do so, specifying short-term limits. If a request for a permit revision must be initiated by the applicant, the agency should not only irclude short-term 1imits at the firstopportunity, but also encourage the
source to apply for a revisior. 

### At the least, any new levels of increment ard iiAAQS coilsumptior resultiny from a lack of enforceable short-term emission limits must be taken jnto account infuture PSD permit analyses. If increment
or NAAQS exceedances are predicted by the new analysis, the review agency in:ist act to prevert sucii exceedarces. The review agercy must also estabiish
a policy providirg short-term 

### Iirnits on PSD permits to protect shol't-term

;"r'.,n > , . 1. d?d >!,$t!lX.

I,-. fj.
, 

# , , 

## , ti?. ;IOS 5

## ,: $3

### Ie zxc?(>ti 

### or of thcsc sour-ces fa11

### irig u?der. :paragraph (3) 3'39ve, owers arc operatcrs 3: sosrces witii 2SD peri!!i 

### ts i.iisiiirg to take acvartage of the relief from solfur variab.ility offered by the rollirg30-day average NSPS must apply for a PSD permit change and obtair a revised permit 

### if exceedance of the NSPS or 

### BACT emission level on a short-term (including aever-to-be-exceeded and 

### 3- or 24-hour) basis is anticipated. To be granted, these permit change requests mu8t meet two criteria: (1) The source nust de~nors trate that ary BACT level of compliance embodied ir the permit (ircludirg BACT 1imits with shorter averaging times as well as more stringent 1imits) is either (a) no longer feasible on either a technological
or economic basis, or (b) wi11 sti11 be ensured by the use of the longer .term average. (2) The source must demonstrate that neither the NAAQS nor the increments for SO2 would be exceeded (as demonstrated by dispersion modeling) by afiy revised short-term emission 1 imits contained ineither permits or the SIP.During the processing of such requests, the review agency must take the opportunity to provide specific emission 

### 1imits or other permit conditions which protect all applicable NAAQSand PSD increments. A1 though itis EPA's pol

### iiy that the emissions limi ts used to determine compliance with short-term increments and NAAQS are enforceable even ifsuch limits are not specified ir the permit itself, €PA strongly encourages the inclusion of all applicable emissions limits, operating parameters, fuel specifications, 

### - averaging times, compliance nietliods, and other requirements inthe permit. Such action 

### will both decrease uncertainty regarding the limitatiocs a source mu8t meet and reinforce the legal basis of such 1

### imitations. The 

### ijrni tatiocs, to be fillly effective, nus

### t specify averagi~g tim?s corresponding to ace or more short time periods consistent with the limiting Psi) iccrement
or !.:?,AQS (e.g., pounds S07 per hour). A 

### iimitatioo such as pounds SO2 per
rii I

### Ibr btir neat, irput 

### is an excellent control techrology 1

### imitatioc, hiit he trie iieat input (So: !er !o?,d) 31. thee:iiissions per unit of time inust also be 1inited to provide anibiect air impact protection. 

### 5. Subpart Da Sources On June 

### 11, 1979 (44 FR 33580), EPA promulgated new requirements for electric uti

### lity boilers (Subpart Da sources). These new requi:-ements, actually ineffectsince September 18, 1978 (43 

### FR 52154), specified a rolling30-day average NSPS for SO2 for new Subpart Da sources. PSD permits issued sunsequent to these ciates, a1though irtecded to protect short-term
as well as long-term increments and standards, may specify in the permit only the rolling30-day average NSPS as an SO2 emission limitation. This situation differs from that.of Subpart D sources ir! that the NSPS for Subpart Da sources was not applied retroactively to sources alroady permitted; the Subpart Da permits were issued by review agencies 

### with ful

### l know1edge that the 

### SO2 NSPS was a long-term (rolling30-day average) limitation. EPAcannot presume that agencies considered the revised Subpart Da 

### NSPS to be a "never-to-be-exceeded" short-term emission limitation as was assumed for the Subpart Dsources. As a result, EPA's policy regarding PSD permits for Subpart Da sources is this: 

### (1) If the 

### PSD permit contains (or incorporates by reference) short-term 

### S07 emissions limits, those limits must also (in addition to the Subpart Da 

### NSPS) be met by the source acd presumably represent BACT. The emission 

### 1imit averagirg times, ever 

### if not specifically stated (e.g., pounds per hour), are considered short-term averages as long as itcan redsorably be p:.iisu;iied that they were carsidered as such (e.g., 

### - by use of such liiiiit in model

### iry 3-hour or 24-nour ainb<e~t impacts). These enissiocs 1 <mi ts ther coinjrise e:r'orcea!)!ir silar

### c-ierin !im; ts wh;ch adequately protect the :<-hour
8y.3 '2-i?aijr 

### i c :;A,\?S a

.... 7:.,-If: ti7.e Ci;g 3cmci't; !jr~?s.?ot cartair: (or ificorporate ; rsferefice) t L,,, ,. ., , i- i snort-term SO? einissioi: 1:'mi ts adequate to protect short-term ircreinents and 

### NAAQS, the review agercy responsible for PSD permits must take the followiny actions withii: six months of the date of publication of this policy 

### :'c tlie FEDERAL REGISTER. (a) Reassess short-term impacts for all such sources on the basis of naxiaum articipated short-term emissions and take these new ificreinent cor.sumption levels irtoaccoupt ir future PSD permit analyses. (b) If increment exceedances are predicted by the new analysis, develop
a revision to the SIP to prevent such exceedances. (c) Develop and iinp:..-riiert a policy or reyulatior! requiring short-term 1iinits inPSD permits that adequately protect short-term increments.A report to EPA on the actions taken and the sources acd areas affected by these actions must be submitted by the responsible review agency within 

### 8 months of publication of this policy inthe FEDERAL REGISTER. 

### C. ~aximurn Anticipated Short-Term Emissions Normally, ambient air impacts during permit processing are based on maximum allowable emissions since the source is notyetoperating. Then, when the source begins operatiny, impacts are based on actual representative em;ssions. In these Subpart 

### D and Da NSPS cases, however, not only is the soiurce likaly to already be inoperation (which calls for use of actual en:'ssions), but also there may not be any specified short-term emission


# ,2F ;


## . .,n.:a tioc (so that roa! I~i~able em;ssion limits are specified). S\i'ce these sourc?s have been issued PSD permits (if the PSD permit has cotyet b2_.!: isSii2d ~. 

## , L' ~nere is 

### s

### ti !i opportur:ity KO -include !n the perinit short-terin

. 

## . .: ., ,.-..?:

.,

# - 

# . .,,

# ."11:::; 

### Ir, ti;i:s a,~~ooiiil:i:~ this p:-oblem), ir?formatior:on fuel-sulfur ,i;--ab<.]{.bj, si>oii!d i?b.!e.

. For exa~pjethe 24-h~uraverage f';le;.

. , ,,.. . ., .. ,.-, , sdinjjles or 24-hour CEM averages required by the NSPS for calculating rolling 30-day averayes can be used directly to determine the variatior in24-hour SO2 emission levels that can occur with the specific fuel beicg used by a sl~ecific source. Standard statistical techniques can determine the 3 siyma upper bound on the values and this 3 sigma value can be used as the maximum a?.t;cipated 24-hour emissioas level. I? aaditioc, the range of anticipated 3-hour emission levels can be derived froin the 24-hour averages, a series of 30-day averages, and the annual a,verage. From this range of 3-hour values, an equivalent 

### 3 sigina maximum anticipated 3-hour emissicr level can be derived. Itshould be noted that these short-term "maximum anticipated" emission levels are not enforceable (unless incorporated--specifically or by reference-- ipto.the applicable regulation or permit). They are instead a statisticalestimate of the actual short-term emissions anticipated ata source based
on the characteristics of the fuel that source is using. As such, they constitute an estimate of actual short-term emissions that can be used to
assess short-term ambient air impacts inlieu of specific 1 imitations. 

### D. Compliance with Short-Term Emission Limitations Inan effort to balance the cost of gathering data and the need for data to determice compliance 

### with short-term emissions 1 

### imits, EPA ir? today's policy is placirg niost of the emphasis on 24-hour average emissiors data. There are two reasons for this: (1) The NSFS for Subpart D and Da sources require that collection of 

### ~ata be based on 24-iiodr tine periods. The average of 30 of these 24-hour average eniissiors :-ates is the erforceable 1 imit, but the emissions rates
are availaSi@d-d ;!ie ~iior; tori~lg equiI,inert ir place as a resui

### t crf the 

### I<S?S

p?t



# :. .- , 

### At riics

### t, tijtldy's pol<cy ?ti

### i 

### 1 requ:re ol?iy that d3ta be collecieti

. . . ,,, - ,2rd.r;lpcrtes-

### ?s 'c:'ivi d;.i5,1 .?S..i?o:~c a5d.e?agej $3. additior to the.ro;

### 1irg

. . , . , ,, . 3C-day average. 

### (2) For iiiacy 

### of these sources, the fuel is handled insuch yuantities that
even ifdata on emissions are available almost immediately, littleor nothing could be dore. For example, a low sulfur coal-fired boiler bunker inay hold
an 

### 8 (or more) hour supply of coal; even if a CEM is inuse (rather thar! fuel sarnpl'irg) 

### , the krowledge that d 3-hour average 1{mit has just been exceeded does little good; there is arother 

### 5 (or more) hour supply of coal in the burker which has to be burced before any corrective steps (such as blending 

### ir a lowr sulfur coal) take effect. Fuel sampling analysis (FSA) increases
even further the time required to respond because 

### ittakes longer to obtain the sampling results. From the above, itfollows that the best approach to compliance with
a 3-hour average emissions limitis to project, based on sampling datarepresenting either the sulfur content of the fuel or sulfur dioxide emissions, tne maximu~n anticipated 3-hour average emissions rate. As long as the projected rate is 

### less than the a1lowable short-term emissions limit, the source wauld be considered in compliance with the 3-hour emmission limit, with one exception: if3-hour average emission rate data are available (e.g., 

### - from a 

### CEM or stack testing) acd show exceedance of the 3-hour average a11 owable limi

### t, then the 3-hour data can provide the basis for a noncompliance determination. Thus, today's policy is that for 

### PSD emissions limitcompliance purposes, S!~bpart D and Da sources need gather only 24-hour average emissions data, ?Sit< a !nethod (CEM or 

## is:\) specified by the appropriate NSPS. The 24-hotir 3>,erayes must, however, be reported individually rather than as rolliag30-day
~3

.<,c2 cs, ,.,- a::d 

### a statistical aralysjs iriust be corducted iri tially, tiler: arr~ally 

### (
..,. -':>rs .- wa:-~i:ci .ir! :.:ri tirc; 

### !,y the revfew agency) ai?d whe;?ever the ::re1 s;ilfli?



### t (i: .-t.rms 3fprgt~r:?~ .~f.-Ei+ per:m;'.ll.jor $tu)inay.have.chafiyed as , .. . . eglderced by (1) use of fuel froin a differentsource, or (2) evidence of
a c?,aage inche average sulfur coctect of the fuel or sulfur dioxide emissions rate of the source. Sources subject to tile rolling30-day average SO2 NSPS must submit their ici tial report to EPA by 

### (6 months from the date this policy is proposed 

### i r the FEDERAL REGISTER). The ici tial report shall include sufficient 24-hour average einissiorc rate data to demonstrate (1) compliance with any 24-h3ur emission 1intitatioa, and (2) that24-hour SO2 increment exceedances
are not being caused or contributed to by the source. Inaddition, the .reportshall include a stetistical analysis (or specific sampling data) showing the maxinium anticipated 3-hour average SO2 emissions rate expected to occur. Subsequent reports of 24-hour average 

### $02 emission rates are to be subinitted with the NSPS emissions data.VIII. AMBIENT IMPACT EQUIVALENTS Proposed changes to permits can affect the ambient air impacts of a source without changing the level of emissions from the source. For example,
a shorter stack could increase ground level ambient impacts; so could relocation of a planned emissions unit closer to the source's restricted access boundary. Proposed changes of this type must also be taken into account, and today's policy proposes doir!g so by establishing the concept of equivalent ai?b;ent iinpacts. When a change is proposed which would result ir! changes inthe source's arnbient impacts, today's policy proposes the following (unless some other 

### ij?cct ~f 

### tli? change req~iirss inore extens'ive docuinentatior! or review): (1) i?ecreases inambiert air impacts are processed as aidnSristrative c';qes.



## . . (2) Ii::reds~?s I.

### rn5? 3 1"i)acts are subjected t3 a;~pro?riate .?e?siorl?ode-l.ins. to-rietermine t!?e equiv21ent eniss-ions.<ncrili?se from the

. ,.. p!-eciiange source or emissiocs unitwhich would produce the same ?rnpactas t'ne proposed change. The equivalert emissions level isused to determine whether the proposed change isminor or significant. Inmany cases, ambient impacts, once modeled, are proportioral to emissions increases and decreases; if, for example, emissions double, the anihient impact doubles. For such cases, the equivalent emissions increase
csr 3e determined 

### by ratio: 

### E = Eo (In/Io) 

# - Eo where: E = "equivalent" emissions rate change, grams per second Eo = original. (prechange) emissions rate, grams per second I, = postchange ambient impact, micrograms per cubic ineter 

### 1, = prechange ambient impact, micrograms per cubic meter

### 1, and lo, must be based on the same averdying time and must represent the maximum ambient air inipact increase resulting from the proposed change. If there isco proportional relationship between emissions acd ambient impacts, dispersioc modeling usicg different emissions rates may be necessary to determine equivalents. Ac,y such complex cases should be handled by appropriatemodelicg experts. IX. CONCLUSION 

### i4e be1ieve tliat today's proposed pol.icy statement addresses the classificatior! and processicg of the types of change requests most often referred to EPA 

### for col?suItation. Because of the wide range of activity sdbjeit 

### to proposed scjiirce cliar!ges, the Agercy especSally solicits commect frsm 

### tllo~i? with experi2cce i this area regardicg whether additioedl issues toi,jcs silodid 

### Se 

### ..i,,,- , cliid~d. 

### S‘;miiarly,EPA 

### seeks cominect reyarairg 

### the ,111:tcintiai f of int 

### y?w?al dpprodch deviijoped for 

### processirg



### - Admicis

### trator