# Petition for Writ of Certiorari — Ohio Power Co. v. United States Environmental Protection Agency > Briefs, arguments, decisions, and more. URL: https://www.frixlaw.com/law-library/documents/brief%3Amicro_IA40385010_2577%3A1 ## Record - **Collection:** Supreme Court brief - **Document type:** Petition for Writ of Certiorari - **Published:** January 1, 1984 - **Citation:** 469 U.S. 1034 ## Text Office -Supreme Court, US. Fill kED AUé’S 1984 84-195 No. ——_—— ; ; ee eT racenpenacieiasicicsichiadteriemasiedans “3 | _ CLERK IN THE Supreme Court of the United States ‘OCTOBER TERM, 1984 OHIO PowER COMPANY, - — Petitioner, Vv. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY, WILLIAM D. RUCKELSHAUS, ADMINISTRATOR, Respondents. PETITION FOR A WRIT OF CERTIORARI TO THE. UNITED STATES COURT OF APPEALS FOR THE SIXTH CIRCUIT ? EDWARD BERLIN Counsel of Record for Petitioner FRANCIS S. BLAKE SWIDLER, BERLIN & STRELOW, CHARTERED 1000 Thomas Jefferson St., N. W. Washington, D.C. 20007 ; (202) 342-5500 . A. JOSEPH DowD ’ JEFFREY P. WHITE OHIO POWER COMPANY E. DONALD ELLIOTT Box 401A Yale Station New Haven, Connecticut 06520 Of Counsel WILSON - EPES PRINTING Co., INC. - 789-0096 - WASHINGTON, D.C. 20001 aa QUESTION PRESENTED May a court, which has held an administrative rule arbitrary and capricious, authorize an agency to limit’ its inquiry on remand to the “further study” of a single “issue,” notwithstanding the mandate of the Administra- - tive Procedure Act that agency action held to be’ arbi- trary must be set aside and returned to the\agency for repromulgation and the requirement of Article III of the ‘Constitution that courts must review the agency action in controversy, not abstract issues? * (i) ii PARTIES TO THE PROCEEDING BELOW Parties before the Court of Appeals in addition to Petitioner and Respondents named in the caption of this case were Columbus & Southern Ohio Electric Company, _ Dayton Power & Light Company, Peabody Coal Company, and the Commonwealth of Pennsylvania.* LIST OF PARENT COMPANIES, | ‘SUBSIDIARIES AND AFFILIATES A listing of parent companies, subsidiaries and af- filiates of Petitioner as required by Rule 28.1 of the Supreme Court Rules is as follows: Petitioner Ohio Power Company is a subsidiary of American Electric Power Company, the affiliates. and subsidiaries (other than wholly owned subsidiaries) of which are: Appalachian Power Company Cardinal Operating Company Columbus & Southern Ohio Electric Company Indiana Kentucky Electric Corporation Ohio Valley Electric Corporation * Additional parties appeared before the Court of Appeals in the initial proceeding leading to the remand of an “issue” to the agency (Shell Oil Co., Austin Powder Co. and E.I. duPont deNemours & Co.). Those parties were not involved in the deci- sion leading to the final judgment at issue in this case. TABLE OF CONTENTS I ie occvecenncsoecnaconiacens I his CONSTITUTIONAL AND STATUTORY PROVI- SN ssid nnccdckianaciscswnssdinessnashctsbsieonnssssoeess STATEMENT OF THE CASE W002... REASONS FOR GRANTING THE PETITION .......... The Decisions Below Raise Important and Unset- tled Questions of Administrative Law on Which There Is Conflict among the Lower Federal Courts.. A. The Lower Court’s Failure to Set Aside and Remand for Repromulgation Is Inconsistent with Congress’s and this Court’s Delineation of the Proper Relationship between Courts and Administrative Agencies ........00000000022- 0. B. The Lower Court’s Limitation of Judicial Re- view to the “Issue” Remanded to the Agency Is Inconsistent with the Proper Function of Judicial Review under Article III of the Con- a a salsa behlpnenencpaiaduns Ea a APPENDIX: . Opinions of the Court of Appeals —.........0.0000000000000... Decisions of the United States Environmental Pro- RETR EERE Judgments of the Court of Appeals Order of the Court of Appeals Denying Rehearing Se cece Constitutional and Statutory Provisions Involved.. (iii) 11 16 18 94a 98a 99a iv TABLE OF AUTHORITIES ~ Cases: Page Action on Smoking and Health v. CAB, 713 F.2d oR + _; RENT eNO RE ene eam 7,10 American Meat Institute v. EPA, 526 F.2d 442 A I ci sss te atcnmbbiineebe Redeigaiens 7 Buckeye Power, Inc. v. EPA, 481 F.2d 162 (6th Cir. 1973), cert. denied, 425 U.S. 934 (1974)... 12 Burlington Truck Lines v. United States, 371 U. S. OU i ae al cahasintis 15. California Cartage Co. v. United enema 721 F.2d I I soe ics dateaietenacaccctennsectianimnsicoes 7 Camp v. Pitts, 411 U.S. 135 (i978) OPENS AS 7-11 Central Power & Light Co. v. United States, 634 ¢ # 8 ge Th. : eeieie eee ce Cincinnati Gas & Electric Co. v. EPA, 578 F.2d 660 (6th Cir. 1978), cert. denied, 489 U.S. 1114 ¢. : | Eaaeneee POY ILD OL SIRS IO ee ORAL TE 2, passim Citizens to Preserve Overton Park v. Volpe, 401 Oa a eee 8-11 Cleveland Electric Illuminating Co. v. EPA, 572 F.2d 1150 (6th Cir. 1978), cert. denied, 439 U.S. i caiaediiclinien 3 Columbus & Southern Ohio Electric Co. v. ‘Guile, 638 F.2d 910 (6th Cir. 1980) ...........002220000222...2...- 5 EDF v. Costle, 657 F.2d 275 (D.C. Cir. 1981)........ 7 FCC v. Pottsville Broadcasting Co., 309 U.S. 134 RAB. SR SR eI LTE TY PR 13, 17-18 FCC v. Schrieber, 381 U.S. 279 (1965) .................. 13 Federal Radio Comm. v. General Electric €o., 281 ee Sg ENE By nen es rene oe eaten 17 FMC Corp. v. Train, 539 F.2d 973 (4th Cir. 1976)... 7 Ford Motor Co. v. NLRB, 305 U.S. 364 (1939)... 15 PC v. Transcontinental Gas Pipe Line Corp., 423 Oe 9,13 ‘Harrison v. PPG Industries, Inc., 446 U.S. 578 Bee, aR EE RR Ae NIeTe tare Pe RCN eC IG ear 8-9 __) Montana-Dakota Utility Co. v. FERC, 631 F.2d Ie 7 National Lime Assoc. v. EPA, 627 F.2d 416 (D.C. aerate crt ace ER th eae ah ee RROD 12 Vv TABLE OF AUTHORITIES—Continued Page NRDC v. EPA, 494 F.2d 519 (2d Cir. 1974) . eee 7 Port Norris Express Co. v. ICC, 687 F.2d 803 SE WIN: I can id onan eka crscaaaausuaiunienioncianenns 7 Public Power Council v. Johnson, 674°F.2d 791 I ON an ubdaucianiomnniaines 9 Rogers v. Hill, 289 U.S. 582 (19338) -................00...... 2 SEC v. Chenery, 332 U.S. 194 (1947) -........00000000.... 14, 15 Tabor v. Joint Board for Enrollment of Actuaries, ee &, Ble A. ys Ren cae 7 Valley Forge College v. Americans United for Separation of Church and State, 454 U.S. 464 I aN ae 17 Vermont ‘Yankee Nuclear Power Corp. v. NRDC, | EE NE TE FD oi inven datnonscrcisincnasaptebacodlbauson 11-13 Statutes and Regulations: Administrative Procedure Act, 5 U.S.C. § 500 et seq. Section 10(e), 5 U.S.C. § 706 .........................- 11-12 Clean Air Act, 42 U.S.C. § 7401 et seq: Section 109(b) (2), 42 U.S.C. § 7409 (b) (2) ..... 11 Section 110(c), 42 U.S.C. § 7410 (c) _20022- 3 Section 165(e) (3) (d), 42 U.S.C. § 7475 (e), (3) (d) ......-.- PRM OS EE AN AS Oe OTS 14 Section 302 (h), 42 U.S.C. § 7602 (h) ....000.......... 11 Section 307 (d), 42 U.S.C. § 7607 (d) _....000. 3, 12, 16 Section 820, 42 U.S.C. § 7620 _........................4.... 14 ' US. Constitution, Article III, Section 2 .......... -10, 16-18 Miscellaneous: EPA Promulgation of State Implementation Plan for the Control of Sulfur Dioxide for the State of Ohio (41 Fed. Reg. 36324 (August 27, 1976) ; 40 C.F.R. Part 52, Subpart KK, § 1881(b) OI vcivciskacilastaatnaetaditce Mek n a ees ee ee Ee ae EPA’s “Reconsideration of the Use of Pasquill- Gifford Dispersion Coefficients for Stability Class A in Setting Emission Limitations for Four Ohio Power Plants” : vi TABLE OF AUTHORITIES—Continued Page Comments Solicited (44 Fed. Reg. 7798 (Feb- SUE Ta TORO. taiicicccnbinicrenisssssadminiiibasioiagninsainn 4 Evaluation of Public Comments (45 Fed. Reg. 41501 (June 19, 1980) ) W000... 4 Denial of Petitions for Reconsideration (45 Fed. Reg. 74041 (November 7, 1980) )........ 4-5 Restart of Compliance Schedules (45 Fed. Reg. _ 73927 (November 7, 1980)) ....................-.-- 4 K. Davis, Administrative Law Treatise, §§ 7.1, 7.2 I i a ee 14 IN THE Supreme Court of the Huited States OCTOBER TERM, 1984 No. —— OHIO POWER COMPANY, . Petitioner, UNITED STATES ENVIRONMENTAL PROTECTION AGENCY, WILLIAM D. RUCKELSHAUS, ADMINISTRATOR, Respondents. PETITION FOR A WRIT OF CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE SIXTH CIRCUIT - Ohio Power Company petitions for a writ of certiorari to review the judgment of the United States Court of Appeals for the Sixth Circuit in this case. OPINIONS BELOW The opinion of the Court of Appeals remanding an issue to the United States Environmental Protection Agency is reported at 578 F.2d 660 (Petitioner’s Appen- dix at 9a-27a) (hereafter referred to as App.). The opinion of the Court of Appeals upholding the agency’s action on remand is reported at 729 F.2d 1096. App. 1la- 8a. The order of the Court of Appeals denying rehear- ing and rehearing en banc is reprinted at App. 98a. The decisions of the United States Environmental Protection Agency are reported at 45 Fed. Reg. 41501, 73927, 74041. App. 28a-938a. 2 JURISDICTION The judgment of the Court of Appeals (App. la) was entered on March 22, 1984. Rehearing was denied on May 8, 1984. App. 98a. This petition is filed within 90 days of the date of denial of rehearing. The jurisdic- tion of this Court is invoked under 28 U.S.C. § 1254(1). The decision of the Court of Appeals remanding an “is- sue” to the U.S. Environmental Protection Agency for “further study” was issued on June 29, 1978. Since that decision did not constitute a final judgment with respect to the controversy presented here, the decision is properly before the Court at this time under Rule 18 of the Su- preme Court Rules; see 28 U.S.C. § 2101(e); see also Rogers Vv. Hill, 289 U.S. 582 (1933). Other aspects of the Court of Appeals’ 1978 decision that were final are not at issue in this case. See Cincinnati Gas & Electric Co. V. EPA, 578 F.2d 660 (6th Cir. 1978), cert. denied, 4389 U.S. 1114 (1979). CONSTITUTIONAL AND STATUTORY PROVISIONS INVOLVED The following constitutional and statutory provisions are involved in this case and are set out verbatim in the appendix, App. 99a-107a: U.S. Constitution Article I{I, Section 2. Administrative Procedure Act, 5 U.S.C. § 500 et seq., Section 10(e), 5 U.S.C. § 706. Clean Air Act, 42 U.S.C. § 7401 et seq., Section 307(d), 42 U.S.C. § 7607(d). STATEMENT OF THE CASE This case involves Ohio Power Company’s attempt to seek judicial review of the United States Environmental Protection Agency’s (EPA’s) action establishing an emission limitation for one of Ohio Power Company’s 3 ; powerplants. EPA promulgated the emission limitation at issue in 1976 pursuant to its authority under the Clean Air. Act." Ohio Power Company first sought judicial review of the emission limitation following its promulgation in 1976. Ohio Power argued that the emission limit was arbitrary and capricious because the computer model EPA used in | establishing the limit was not supported by the record in the rulemaking proceeding. In general, EPA uses com- puter models to predict the air quality impact of a plant’s emissions and then, based-on those predictions, establishes an emission limitation designed to ensure that the plant’s emissions do not violate the National Ambient Air Qual- ity Standards. See generally, Cleveland Electric Illumi- nating Co. v. EPA, 572 F.2d 1150, 1160 (6th Cir. 1978), cert. denied, 439 U.S. 910 (1979). In this case, Ohio Power contended that a critical set of assumptions (called the “Class A” coefficients” )- contained in EPA’s computer _.model were in error and had been discredited by the scientific community. The Court of Appeals for the Sixth Circuit, noting the scientific community’s rejection of the Class A coefficients, held: “On this present record we conclude that United States EPA’s employment of the Class A [coefficients] . . 1s not a rational decision and is arbitrary and capri- cious.” App. 16a. 141 Fed. Reg. 36324 (August 27, 1976); 40 C.F.R. Part 52, § 1881 (b) (47) (1984). Under section 110(c) of the Clean Air Act (codified at that time in 42 U.S.C. § 1857c-5(c) ), EPA promulgated a plan for control of sulfur dioxide emissions, including specific emission limitations for individual sources, for the State of Ohio. The Clean Air Act was substantially amended in 1977 and recodi- fied at 42 U.S.C. § 7401 et seq. (Supp. 1979). The agency’s author- ity to promulgate emission limitations was left intact by the 1977 amendments, see 42 U.S.C. § 7410(c), but the amendments did significantly expand the statutory procedures applicable to EPA’s promulgation of an emission limit, see id., § 7607(d). a 4 Having found the agency’s action arbitrary and capri- cious, the court then described its mandate to EPA: “Our ultimate action on this score is simupiy to remand this issue to United States EPA for surther _ study.” App. 17a. The court did not state in its decision that the emission limitation established by EPA was set aside.” - In the administrative proceedings that followed, EPA read the court’s mand. te as meaning that it could meet its obligations on remand by merely supplementing the record to support its use of the Class A coefficients. EPA ~ announced its intent to develop this supplemental record in February, 1979, and solicited comments for inclusion in the record. 44 Fed. Reg. 7798-7805. In June, 1980, EPA announced its final development of the supplemental record. App. 28a-62a. EPA contended at that point that it had fully discharged its legal obligations on remand by conducting a “further study” of the Class A issue. The agency rejected Ohio Power Company’s argument that it had to promulgate an emission limitation to replace the emission limitation which had been found arbitrary and capricious. In EPA’s view, the 1976 limitation had never been set aside, and the court’s mandate authorized it to conduct a separate proceeding to “study” the Class A issue without connecting that proceeding to the promul- gation of an emission limitation. App. 58a-59a. As a ‘consequence, EPA believed it was only required to show that the supplemental record supported the Class A coefficients, and not the 1976 emission limit. Jd. Ohio Power Company’s petition for administrative re- consideration of EPA’s decision was denied (App. 71la- 93a), and at the same time, the agency announced that 2 The Court of Appeals issued a subsequent decision “clarifying” its earlier order, but again did not indicate that it had set aside the emission limitation. App. 23a-27a. 5 the schedule for Ohio Power Company’s bringing its powerplant into compliance with the 1976 limitation was “restarted,” effective June, 1980 (App. 60a-70a). Following these decisions, Ohio Power Company again petitioned the Court of Appeals for review. Ohio Power argued that the emission limitation had necessarily been set aside by the court’s prior ruling that the ageicy’s action was arbitrary and capricious.* Ohio Power re- quested that the case be remanded to EPA for promulga- tion of an emission limitation. This request was not merely a matter of form. The agency, in its efforts to establish the propriety of the Class A coefficients on remand, used a different modeling procedure than it had used in establishing the emission limitation.* It did not, however, use that revised model- ing procedure to reevaluate the propriety of the emission limitation—the most significant matter at issue. Had it done so, Ohio Power argued, a substantially less stringent emission limitation would have resulted. The revised modeling procedure employs the Class A coefficients but results in an emission limitation with which the Com- pany’s plant is already in compliance. Thus, promulga- tion of an emission limitation to replace the one that was held to be arbitrary would moot the entire contro- versy. The costs involved in EPA’s refusal to repromul- gate an emission limitation are substantial—approxi- mately $29 million annually for Ohio Power Company. *Ohio Power Company pointed out that, in another case, the same panel that remanded the Class A issue to EPA had described its remand in this case as having “set aside EPA’s emissions limits.” Columbus & Southern Ohio Electric Co. v. Costle, 638 F.2d 910, 911 (6th Cir. 1980) (emphasis added). Based on that descrip- tion, it appeared possible—at least prior to the court’s March, 1984, decision—that the court’s failure to state that it had set aside the emission limitation was inadvertent and that the court would reject EPA’s interpretation of the remand order. * The revised modeling procedure was based on both a new model and different input data. App. 87a-90a. 6 The Court of Appeals, however, refused to address any issues relating to the emission limitation. It ruled that the emission limitation was not at issue in the case, since it had “carefully limited the remand to a single issue and we should now decide only that issue.” App. 6a (emphasis added.) That issue was: “[{W]hether or not the EPA, since the remand, has properly carried out this court’s mandate to undertake further study of the basis for the use of Class A coefficients.” App. 5a. Having narrowed its scope of review to the single issue of whether the agency had conducted “further study” of the Class A issue, the court then found that EPA “did re- consider and introduce into the record additional support for its original finding that the . . . Class A coefficients should be used and we now affirm.” App. 6a. REASONS FOR GRANTING THE WRIT This case presents an important and unsettled aber of administrative law: Whether a court must set aside an agency rule that it has found to be arbitrary and capri- cious and remand it to the agency for repromulgation in vompliance with the relevant statutory requirements. The two Sixth Circuit decisions at issue here® stand for the proposition that a court has the authority to remand selected “issues” to an agency for “further study” with- out setting aside the rule found to be arbitrary and ca- pricious and without requiring the agency’s rule to be repromulgated. | This approach conflicts with that taken by the majority of lower federal courts, which have held that the proper 5 As indicated in the Jurisdictional Statement, both decisions of the Sixth Circuit are appropriately before this Court for review since the 1978 decision was not a final judgment. See p. 2, supra. 7 remedy for an arbitrary and capricious agency action is “to vacate the action and to remand the matter back to the agency for further consideration.” EDF v. Costle, 657 F.2d 275, 285 (D.C. Cir. 1981); see also California Cartage Co. v. United States, 721 F.2d 1199, 1202 (9th Cir. 1983); Action on Smoking and Health v. CAB, 713 F.2d 795 (D.C. Cir. 198%); Port Norris Express Co. Vv. ICC, 687 F.2d 803 (3d Cir. 1982); Central Power & Light Co. v. United States, 634 F.2d 137, 150 (5th Cir. 1980) ; Montana-Dakota Utility Co. v. FERC, 631 F.2d 557, 562-63 (8th Cir. 1980); Tabor v. Joint Bd. for En- _ rollment of Actuaries, 566 F.2d 705, 711-12 (D.C. Cir. 1977). Decisions from other lower federal courts, how- - ever, have taken an approach similar to that of the Sixth Circuit. See FMC Corp. v. Train, 539 F.2d 973, 985 (4th Cir. 1976) (standards set under Clean Water Act “re- manded to the Agency for further documentation’) ; American Meat Institute v. EPA, 526 F.2d 442 (7th Cir. 1975 (remand for the Agency to consider whether evi- dence already in the record would support rule); NRDC v. EPA, 494 F.2d 519, 526 (2d Cir. 1974) (remanding agency action based on “unrealistic” computer model for further study on specific issues) .® ' This Court has not directly addressed the issue of the type of remand necessary after; an agency rule is invali- dated. The Court’s decision in Camp v. Pitts, 411 U.S. It should be noted that the circumstances presented in the above cases vary. In American Meat Institute, for example, the court offered the agency the alternative of supporting its arbitrary and capricious regulation with evidence already in the record but not previously relied on. The agency would be allowed to follow that course of action without repromulgating the regulation. The court also made it clear, however, that if the agency developed new evidence for the record, it had to repromulgate the rule. 526 F.2d at 467. The Seventh Circuit’s action, therefore, is a more moderate version of the Sixth Circuit approach, which authorized the agency to introduce new evidence into the record without repromulgation of the rule. g 135 (1973) (per curiam), holds that an arbitrary agency decision “must be vacated,” id. at 148. However, since the agency action at issue in Camp v. Pitts did not in- volve an exercise of agency rulemaking authority, the Court did not deal with the scope of the ensuing remand. The Court should grant certiorari in this case to resolve the confusion among the lower federal courts and to clarify the principle stated in Camp v. Pitts for agency rulemaking. The statutory, constitutional and policy issues involved are substantial. The scope of a court’s remand authority relates directly to the question of the proper boundaries of the relationship between courts and administrative agencies; the proper interpretation of the Administrative Procedure Act; and the “case or con- troversy” requirement of Article III of the Constitution. The present case is, moreover, a suitable one for the res- olution of these issues, since the Sixth Circuit’s failure to set aside the agency’s action and remand for reprom- ulgation has a substantial practical impact, amounting to nearly $30 million per year for Ohio Power Company. THE DECISIONS BELOW RAISE IMPORTANT AND UNSETTLED QUESTIONS OF ADMINISTRATIVE LAW ON WHICH THERE IS CONFLICT AMONG THE LOWER FEDERAL COURTS This Court’s decisions bracket, but do not directly address, the issue of the proper scope of a remand order following a decision that an agency has acted arbitrarily and capriciously. In Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402 (1972), the Court held that a limited remand for an explanation of agency action is appropriate if the grounds for the agency’s decision were not adequately disclosed on the record. See Camp Vv. Pitts, 411 U.S. 138, 143 (distin- guishing Overton Park); see also Harrison v. PPG In- dustries, Inc., 446 U.S. 578, 594 (1980) (reviewing court” » > may remand for further administrative proceedings if 2 nee Ne Ome eae beee: ML ae een oo. er 9 the record is inadequate to permit “informed judicial review”). The purpose of the limited remand in that circumstance is ‘to aid the court in its review, and the limited remand is issued without the court’s reaching a determination on the arbitrarmess or rationality of the rule. See, e.g., Public Power Council v. Johnson, 674 F.2d 791 (9th Cir. 1982). The Court’s decision in Overton Park, however, does not sanction limited remands for supplementation where the record before the court and the agency’s explanations for its findings and actions are sufficiently developed to allow judicial review. This distinction was clearly set out in Camp V. Pitts. The Court in Camp stated that, where the record is adequate for judicial review “[t]he validity of the [agency’s] action must stand or fall on the propri- ety of that finding, judged, of course, by the appropriate standard of review.” Camp Vv. Pitts, supra, 411 U.S. at 143; see also FPC v. Transcontinental Gas Pipe Line Corp., 423 U.S. 326 (1976) (per curiam). This case falls squarely within the situation described by Camp. The record before the court was fully adequate to permit judicial review, and the court never suggested otherwise. The court’s assessment, based on the record, was that EPA’s use of the Class A coefficients to estab- lish the emission limit was not a “rational decision” and was “arbitrary and capricious.” App. 16a. Having reached that conclusion, however, the court’s next step was to remand the Class A “issue” for “further study.” Its apparent conclusion—subsequently made explicit in its decision after the remand proceedings—was that the agency could enforce its original rule if it supplemented the record on that one issue. In Camp v. Pitts, the Court was not faced with the issue of determining the scope of reconsideration on re- mand necessary to resurrect an invalid rule. The agency action at issue in Camp was not subject to rulemaking 10 procedures. As the Court noted, “neither the National Bank Act nor the APA requires the Comptroller to hold a hearing or to make formal findings on the hearing records when passing on applications for new banking authorities.” 411 U.S. at 140-41. . A recent case interpreting Camp has pointed out: “Where, as in Camp ..., the agency’s explanation is required to be responsive to the purposes of the en- abling statute, rather than to a record developed through mandatory hearings or public comments, post hoc rationalizations, while undesirable, are not fatal.” Action on Smoking and Health v. C.A.B., 713 F.2d 795, 798 n.2 (D.C. Cir. 1983) (citations omitted). The court in Action on Smoking and Health went on to address the open issue of what “steps an agency must take to enter a valid new order... .” Jd. at 798. The D.C. Circuit concluded that the agency had to conduct a new inquiry, adhering to the same statutory require- ments applicable to the initial promulgation. Facing the situation left open in Camp, the court reasoned that repromulgation was necessary to prevent post hoc ration- alizations on the part of the agency and to provide the parties on remand the full benefit of the applicable statu- ' tory provisions. Id. The Sixth Circuit’s contrary conclusion in this case raises two distinct, though interrelated, issues: First, whether the failure to set aside an invalid rule and remand for repromulgation is consistent with Congress’s and this Court’s delineation of the proper relationship between courts and administrative agencies; and, second, whether the lower court’s subsequent limitation of judi- cial review to the “issue” remanded to the agency is con- sistent with Article III of the Constitution and the prin- ciples governing judicial review of administrative action. u A. The Lower Court’s Failure to Set Aside and Remand for Repromulgation Is Inconsistent with Congress’s and this Court’s Delineation of the Proper Relation- ship between Courts and Administrative Agencies. The lower court viewed its reihand for supplementa- tion as flowing from the proper rélationship between courts and administrative agencies as outlined by this Court’s decisions.’ The court noted that “decision-making (particularly in this highly technical’area) is the primary responsibility of the agency and not the responsibility of this court,” App. 16a, citing Vermont Yankee Nuclear Power Corp. v. NRDC, 435 U.S. 519 (1978), and Citi- zens to Preserve Overton Park v. Volpe, 401 U.S. 402 (1971). The court apparently viewed a remand for “fur- - ther study” as a less “intrusive” judicial action, and thus more in keeping with the spirit of Vermont Yankee and Overton Park, than setting aside the agency action and requiring repromulgation of the emission limit. The Court’s approach, however, was misguided and contrary to the spirit of Vermont Yankee. First, the court’s action was inconsistent with the Administrative Procedure Act (APA). The Sixth Cir- cuit’s initial review of EPA’s action was governed by the 7 The court may also have been influenced in its choice of a re- mand approach by its perception of the health hazards posed by powerplant emissions. App. 2a-4a; 6a. It is important to note, how- ever, that the court misunderstood the purpose of the emission limi- tation at issue in this case. The limitation was set to protect the “secondary” national ambient air quality standard, not the “pri- mary” standard. The primary standard is designed to protect health; the secondary standard is designed only to protect other general “welfare” concerns (e.g., vegetation). 42 U.S.C. §§ 7409 (b) (2); 7602(h) (defining “welfare” considerations). Indeed, EPA never claimed that the limitation was necessary to protect public health and stayed enforcement of the limitation pending its Class A “study.” App. 64a. 12 judicial review provisions of the APA, 5 U.S.C. § 706,” which state: The reviewing court shall— . (2) hold unlawful and set aside agency action, findings and conclusions found to be— (A) arbitrary, capricious, an abuse of discretion or otherwise not in accordance with law; .... 5 U.S.C. § 706(2) (A) (emphasis added). There is nothing in the Sixth Circuit’s opinion, how- ever, to suggest that the court recognized that the lan- guage of the APA constrained its choice of a remand order. Yet the Congressional instruction is unambiguous that the court “shall set aside” arbitrary and capricious rules. The APA certaintly contains no Congressional authorization for a limited remand of an arbitrary and capricious rule for “further study.” This Court has previously noted that the requirements of the APA represent a “statutory scheme through which Congress enacted ‘a formula upon which opposing social and political forces have come to rest.’” Vermont Yankee Nuclear Power Corp. v. NRDC, supra, 435 U.S. at 547 (citation omitted). The Act’s requirement that arbitrary rules be set-aside serves several vital purposes: It acts as a restraint on judicial review by ensuring that agency 8 The court’s review of EPA’s actions under the Clean Air Act, as in effect when EPA promulgated the emission limitation at issue, was governed by the judicial review provisions of the APA. 5 U.S.C. §§ 701-706. See Buckeye Power, Inc. v. EPA, 481 F.2d 162, 171 (6th Cir. 1973), cert. denied, 425 U.S. 934 (1974). The Clean Air Act Amendments of 1977 contain their own judicial review provisions modeled after the APA. 42 U.S.C. § 7607(d). The language in the Clean Air Act now states that the reviewing court is to “reverse any .. . action found to be—arbitrary, capri- cious... .” Id. § 7607(d)(9)(A). The legislative history of the 1977 Amendments clearly indicates that this language was in- tended to parallel the APA, see National Lime Ass’n v. EPA, 627 F.2d 416, 452 and nn. 126-27 (D.C. Cir. 1980). 13 action will not lightly be found arbitrary; it obviates the Due Process concerns that would be raised by an agency’s attempting to enforce an arbitrary rule during the pen- dency of a remand; and it protects the integrity of the administrative process. The latter point is particularly important in this case. In the past, this Court has struck down lower courts’ attempts to impose particular procedures on remand. See Vermont Yankee Nuclear Power Corp. v. NRDC, supra, 435 U.S. at 542-49 (court order requiring rulemaking process on remand to include more extensive procedures) ; FPC v. Transcontinental Gas Pipe Line Corp., supra, 423 U.S. at 333 (court order requiring agency to study issue of natural gas shortage); FCC v. Schrieber, 381 U.S. 279, 290 (1965) (court order requiring confidential pro- ceeding on remand) ; FCC v. Pottsville Broadcasting Co., 309 U.S. 134 (1940) (court order requiring agency to conduct proceedings on remand based on then-existing record). In this case, rather than imposing a special procedure on the agency, the court authorized a special procedure. The remand order was then used by EPA as justification for limiting its scope of inquiry to the Class A issue and for ignoring the ultimate question of the validity of the emission limitation.? The court’s authorization of the truncated inquiry on remand harms the administrative process as much as the imposition of special procedures in cases such as Vermont Yankee. It is not the province of a reviewing court to assume that an arbitrary and capricious rule can be cured by ® For example, in denying Ohio Power Company’s petition for reconsideration, EPA briefly discussed the differences between the modeling procedures it used in setting the limitation and those it used to “study” the Class A coefficients. In that discussion, the agency simply concluded that the differences were insubstantial for purposes of its “study,” but never addressed whether those differ- ences "vould result in a changed emission limitation. App. 87a-90a. 14 studying and supplementing the record on one particular factual issue. An agency rule is an amalgam of factual findings and poliey considerations applied to yield a final action—here, an emission limitation. K. Davis, Adminis- trative Law Treatise, §$ 7.1. 7.2 (1979). Removal of one finding from the jackstraw pile of findings and policy considerations that comprise the agency’s final action can have effects that the court, lacking in technical expertise, cannot anticipate. See SEC Vv. Chenery, 332 U.S. 194, 195-97 (1947). That is well-illustrated in this case. The computer models EPA uses to set emission limita- tions are, in essence, sophisticated methods for processing facts (data) in accordance with a given set of assump- tions (such as the Class A coefficients). Changes in either the input data or the method of processing the data can alter the resulting emission limitation. The Class A co- efficients can be used to produce any of a variety of results depending on the data and computer model used.” What the court’s remand authorized EPA to do was to “study” and justify the Class A coefficients using a model with a different set of data and assumptions than those used in the model that produced the emission limi- tation. By failing to set aside the emission limitation and remand for repromulgation, the court invited EPA to pull one set of assumptions out of the statutory deci- sion-making context and deprived Ohio Power Company of the opportunity to challenge the connection between the ‘agency’s finding of fact (i.e., the computer model used to process data) and the agency’s action (the emission limitation) .™ 10 See p. 5, supra. 11 Computer models are an increasingly important tool in agency rulemaking. Congress’s concern over the potential abuses of com- puter modeling in the context of the Clean Air Act led it to re- quire EPA to establish uniform modeling techniques and review and update the models periodically as science develops. 42 U.S.C. §§ 7475(e) (8) (D) and 7620. 15 In the context of adjudicatory proceedings, this Court has emphasized that an order remanding an agency ac- tion should not constrict the parties’ opportunity to raise any and all objections to an agency’s action on remand. See Ford Motor Co. v. NLRB, 305 U.S. 364, 374-76 (1939) (a proper remand “does not encroach upon ad- ministrative functions” or restrict the parties’ right to raise all objections to the agency’s action since “the set- ting aside of the findings and order carrie[s] with it the opportunity for reconsideration and the making of a new record”); see also SEC v. Chenery, supra, 332 U.S. at 201 (“after the remand was made.. ., the Commission was bound to deal with the problem afresh, performing the function delegated to it by Congress’). The same principle should apply in the context of in- formal rulemaking. A contrary conclusion would invite post hoc rationaliza- tions. But see Burlington Truck Lines v. United States, 371 U.S. 156, 165-69 (1962). In this case, the court’s re- mand encouraged post hoc findings. It allowed EPA to keep the 1976 emission limitation in place, on the condi- tion that the “further study” of the Class A coefficients resulted in an affirmation of those coefficients. App. 17a. Post hoc supplementation of the record was the path of least resistance, allowing the agency to avoid reconsider- ation of the emission limitation itself. . The failure to set aside invalid agency action thus provides the agency with an excuse for truncating the administrative inquiry. The agency is invited to design the inquiry on remand to satisfy the court’s limited or- der, not its statutory mandate. That is what oceurred in this case, and it affected both the proceedings on remand and the subsequent judicial review. 16 B. The Lower Court’s Limitation of Judicial Review to the “Issue” Remanded to the Agency Is Inconsistent with the Proper Function of Judicial Review under Article III of the Constitution. In reviewing EPA’s response to its remand, the Sixth Circuit held: “Thus the sole issue of practical signifi- cance before this court at this time is the question as to whether or not the EPA, since the remand, has properly carried out this court’s mandate to undertake further study of the basis for the use of Class A coefficients. .. .” App. 5a. In fact, the Class A coefficients in isolation have no practical significance; it is the emission limitation that determines what Ohio Power must do. The issue the court reviewed was whether EPA complied with its man- date of “further study,” not. whether the agency com- plied with Congress’s mandate that its emission limita- tion be rational and supported on the record. 42 U.S.C. § 7607(d). Similarly, the court reviewed whether EPA’s action on remand was adequate in terms of the “further study,” but not whether its action was adequate for the promulgation of an emission limitation. App. 6a, n.2.” In short, the court substituted its interest in the Class A issue for the Congressionally-mandated focus on the ra- tionality of the emission limitation. - In failing to review the issue of the emission limita- tion, the lower court treated judicial review of agency rulemaking as though it were a collaborative process in which the court affirms findings and identifies problem 12 The Court briefly addressed the issue of whether EPA had to comply with the procedural requirements of the Clean Air Act relating to the promulgation of an emission limitation. App. 6a, n. 2. The court held that EPA did not, since its “study” did not involve promulgation of an emission limit and that, in any event, the “study” was done with adequate notice and comment, making the procedural error “harmless.” Jd. The court clearly did not address whether the agency properly reconsidered the emission limitation itself. 17 areas and the agency, in response, must only address the problem areas.’* That approach may be appropriate in the context. of judicial review of a lower court decision but it is inappropriate for judicial review of agency action. See FCC v. Pottsville Broadcasting Co., 309 U.S. 134, 140-44 (1940). As Justice Frankfurter stated in Pottsville : What is in issue is not the relationship of federal courts inter se—a relationship defined largely by the courts themselves—but the due observance by courts of the distribution of authority made by Congress as between its power to regulate commerce and the re- viewing power which it has conferred upon the courts under Article III of the Constitution. Id, at 141, At heart, the error in the decisions below was that the Sixth Circuit perceived its judicial function as though it were reviewing the resolution of the issue of the Class A coefficients and not the action of the agency in imposing an emission limitation. Courts, however, have no author- ity to review issues”; their authority is to review “cases or controversies”. U.S. Const. Art. III § 2, cl. 1; see Valley Forge College v. Americans United For Separation of Church and State, 454 U.S. 464, 472 (1982); Federal Radio Comm. v. General Electric Co., 281 U.S. 464, 469 (1930) (a court on judicial review “cannot give decisions which are merely advisory; nor can it exercise or partici- pate in the exercise of functions which are essentially . . . administrative’) . . 18 The Sixth Circuit was of the view that it had “approved the EPA plan in all respects except one. The exception pertained to the EPA’s employment of the Class A assumption... .” App. 4a. The court did not explain how it could have “approved” the ’ emission limitation while striking down the agency’s use of the Class A coefficients, particularly since the Class A coefficients, as employed in the agency’s previous model, were the determining factor in establishing the emission limitation. See App. 14a. 18 The requirement that arbitrary agency action be set aside and remanded for repromulgation implements the “case or controversy” limitation by ensuring that the court reviews and acts upon the contested agency action and that the proceedings on remand are directed to the resolution of the relevant statutory issues, not the court’s interest in an issue in the abstract. As evidenced by the Sixth Circuit’s decisions, it is en- ticing for a court to limit its remand to “issues.” That approach appears to provide a short cut through what may be perceived as a cumbersome administrative process and a method of limiting the issues for subsequent judi- cial review. But as the court stated in Pottsville, it is an enticement that must be resisted. It is . . . urged upon us that if all matters of administrative discretion remain open for determina- tion on remand after reversal, a succession of single determinations upon single legal issues is possible with resulting delay and hardship. . . . But courts are not charged with general guardianship against all potential mischief. . . . Congress which creates and sustains these agencies must be trusted to cor- rect whatever defects experience may reveal. Inter- ference by the courts is not conducive to the develop- ment of habits of responsibility in administrative agencies. 3 FCC v. Pottsville Broadcasting Co., supra, 309 U.S. at 146. CONCLUSION In several recent cases, this Court has attempted to correct the inclination of the lower federal courts to in- sert themselves into the administrative process and “im- prove” upon the statutory structure created by Congress. This case presents a comparable problem in a different; though equally important, context. The Court should ad- dress the issue of the proper scope of a remand order after agency action is found arbitrary and capricious. 19 The issue is one that arises frequently and the lower courts have reached conflicting conclusions. Several strains from this Court’s prior decisions—the concerns expressed over intrusive judicial review, post hoc agency rationalizations, and the proper role of the courts under Article I[1]—all suggest that the Sixth Circuit’s resolu- tion of the issue left open in Camp was in error. Ohio Power Company has been substantially harmed by that error. This Court should grant certiorari to resolve the issue of the proper scope of a remand order and to clarify the . ‘ application of the principles announced in Camp v. Pitts and Overton Park for agency rulemakings. Respectfully submitted, EDWARD BERLIN Counsel of Record for Petitioner FRANCIS S. BLAKE SWIDLER, BERLIN & STRELOW, CHARTERED 1000 Thomas Jefferson St., N.W. Washington, D.C. 20007 (202) 342-5500 A. JOSEPH DowD JEFFREY P. WHITE OHIO POWER COMPANY E. DONALD ELLIOTT Box 401A Yale Station New Haven, Connecticut 06520 Of Counsel August 3, 1984 APPENDIX =~ —- la APPENDIX UNITED STATES COURT OF APPEALS FOR THE SIXTH CIRCUIT Nos. 80-3561, 80-3730, 80-3732, 80-3813, 77-1367, 76-2090 CHIO POWER COMPANY; CINCINNATI GAS & ELECTRIC COMPANY, et al., Petitioners, Vv. UNITED STATES ENVIRONMENTAL PROTECTION AGENCY and ANNE M. GorsucH, Administrator, Respondents. THE COMMONWEALTH OF PENNSYLVANIA, (80-3813), Petitioner, v. : UNITED STATES ENVIRONMENTAL PROTECTION AGENCY and ANNE M. GorSUCH, Administrator, Respondents, OHIO POWER COMPANY and COLUMBUS AND SOUTHERN OHIO ELECTRIC COMPANY, Intervenors. On Petitions to Review Final Action of the Administrator of the United States Environmental Protection Agency Decided and Filed March 22, 1984 2a Before: EDWARDS, Circuit Judge; PHILLIPS and PECK, Senior Circuit Judges. EDWARDS, Circuit Judge. This appeal concerns the problem of airborne sulphur dioxide emanating from three major power plants located in rural areas in the State of Ohio.t The pollution of the ambient air by sulphur dioxide (produced by burning high sulphur coal), is a medically recognized threat to human health. This is particularly true as to infants, the ill and the aged. It also contributes to acid rain with its subsequent dele- terious impact on the plant and fish life in the lakes and rivers of Ohio and neighboring states. Indeed it is al- leged to contribute to the latter type of pollution in down- wind areas as far removed as New England and East- ern Canada. The fundamental issues of this case were dealt with and decided over five years ago in Cleveland Electric Illuminating Co. v. EPA, 572 F.2d 1150 (6th Cir. 1978) and Cincinnati Gas & Electric Co. v. EPA, 578 F.2d 660 (6th Cir. 1978), cert. denied, 489 U.S. 1114 (1979). In those two opinions, this court approved the EPA’s plan for controlling the ambient air affected by four power plants and the Supreme Court denied certiorari. This court’s basic rationale for its approval of the EPA’s air quality standards was (and remains) concern about human hezlth and safety. In our earlier Cleveland Elec- tric decision, we said: 1(1) Stuart (Dayton Power & Light)—now in compliance, but remaining in litigation; (2) Cardinal (Ohio Power Co.)—limits not contested, but if P-G Class A coefficients are again vacated, the limits are once again in question; and (3) Muskingum River (Ohio. Power Co.)—only plant in which emission limitations are still contested. One petition involved in the original appeal (that of Columbus & Southern Ohio Electric Company’s Conesville plant) has been voluntarily dismissed. 3a The federal Clean Air Act program which pro- duced these standards is based primarily upon the adverse effect which sir poiution has upon human life and health. 3 Acute episodes of high pollution have clearly re- sulted in mortality and morbidity. Often the effects of high pollutant concentrations in these episodes have been combined with other environmental fea- tures such as low temperatures or epidemic diseases (influenza) which may in themselves have serious or fatal consequences. This has sometimes made it difficult to determine to what extent pollution and temperature extremes are responsible for the effects. Nevertheless, there is now no longer any doubt that high levels of pollution sustained for periods of days can kill. Those aged 45 and over with chronic dis- eases, particularly of the lungs or heart, seem to be predominantly affected. In addition to these acute episodes, pollutants can attain daily levels which have been shown to have serious consequences to city dwellers. a * o * There is a large and increasing body of evidence that significant health effects are produced by long- term exposures to air pollutants. Acute respiratory infections in children, chronic respiratory diseases in adults, and decreased levels of ventilatory lung func- tions in both children and adults have been found ~ to be related to concentrations of SO, and particu- lates, after apparently sufficient allowance has been made for such confounding variable as smoking and socioeconomic circumstances. Rall, Review of the Health Effects of Sulfur Oxides, 8 Env’tal Health Perspectives 97, 99 (1974). * * * * Two other facts should be added from the exten- sive technical record in this case before we turn to 4a the specific legal issues. The first is that sulfur dioxide emitted from plant stacks reacts with other elements in the atmosphere to form sulfuric acid mist and various suspended sulfates which are in fact the irritants which adversely affect human health. T. Lewis, M. Amdur, M. Fritzhand & K. Campbell, Toxicology of Atmospheric Sulfur Dioxide Decay Products 17 (1972). The second important fact is that these derivatives from sulfur dioxide tend to be airborne for days. They affect areas at great distances downwind, even when in the original sulfur dioxide form they were emitted from a high power plant stack. Rall, Review of the Health Effects of Sulfur Oxides, 8 Env’tal Health Perspectives 97, 106 (1974). 572 F.2d at 1153, 1155. While three of the original petitioners are parties to this appeal, we are advised that two of the four are now in compliance with the EPA standards which we ap- proved in 1978. As to those two appellants, this appeal is in effect a petition to roll back emission standards which are currently being met, and thus to increase SO, emissions in the ambient air in Ohio and elsewhere. As indicated above, the plant not in compliance is Ohio Power Company’s Muskingum River plant. This court, in its opinion in Cincinati Gas & Electric Co. v. EPA, supra, approved the EPA plan in all respects except one. The exception pertained to the EPA’s em- ployment of the Class A assumption in determining pol- lution dispersion under least stable wind conditions in rural areas. As to this issue, we remanded saying as follows: On this present record we conclude that United States EPA’s employment of the Class A assumption in determining pollution dispersion under “least ~ ——— ee « > 5a stable” wind conditions in rural areas and areas of complex terrain is not a rational decision and is ar- bitrary and capricious. As we read EPA’s position on this point, it is that no better solution has been proposed. This answer, however, ignores the Enviroplan and Smith-Singer studies. More importantly, it ignores the conclusions of the experts’ conference convened by Argonne Na- tional Laboratory at United States .EPA’s own re- quest. The report of that conference suggested “elimination of the A curve and the use of the B curve for both A and B stability categories.” See Report of the Specialists’ Conference on the EPA Modeling Guideline, Feb. 22-24, 1977, Chicago, II- linois, at § 2.7.5: “Vertical Dispersion Estimates.” mandate its acceptance by United States EPA. Our ultimate action on this score is simply to remand this issue to United States EPA for further study. This might result in the writing of a new record which supplies the now missing support for the use of Class A coefficients for the least stable wind con- dition in rural counties, or it might result in United States EPA’s adoption of use of the Class B co- efficients for the two least stable wind conditions, or it might result in a new record which supports a: wholly new solution. 578 F.2d at 663-64. Thus the sole issue of practical significance before this court at this time is the question as to whether or not the EPA, since the remand, has properly carried out this court’s mandate to undertake further study of the basis for the use of Class A coefficients and whether, if so, the record now supports EPA’s renewed determintion that the Class A coefficients should continue to be used for power plants in rural areas. By pointing out this proposed solution, we do not 6a We now have this case back before us with many newly stated arguments from EPA’s opponents® and some from Intervenor State of Pennsylvania. After a lengthy hearing (which included the State of Pennsylvania’s contentions), the court concludes that we carefully limited the remand to a single issue and that we should now decide only that issue. This record shows that EPA did re¢onsider and did introduce into the record additional support for its original finding that the Pasquill-Gifford Class A coefficients should be used and we now affirm. Since the beginning, this case has been the subject of careful study by this court because of 1) the complexity and technicality of the record; 2) the economic impor- tance of the decision to the industry concerned; and 3) the health hazards to the general public. Yet our review is limited by a very narrow standard. Congress has provided : (9) In the case of review of any action of the Ad- ministrator to which this subsection applies, the court may reverse any such action found to be— (A) arbitrary, capricious, an abuse of discretion, or otherwise not in accordance with law; 42 U.S.C. § 7607(d) (9) (A) (Supp. I 1977). The Supreme Court has elaborated upon this standard: Under the “arbitrary and capricious” standard the scope of review is a narrow one. A reviewing court 2 Petitioners also contend that EPA was required on this remand to follow the formal notice requirements of § 307(d) of the Clean Air Act, 42 U.S.C. § 7607(d). We agree with EPA, however, that the reconsideration ordered by this court did not constitute either promulgation or revision of an implementation plan. Additionally, if we were to assume the applicability of § 307(d) to this proceed- ing, any deviation from the § 307(d) requirements under the record contained here would be harmless within the meaning of 42 U.S.C. § 7607 (d) (9). a ee ee Ps Ta must “consider whether the decision was based on a consideration of the relevant factors and whether there has been a clear error of judgment. .... Al- though this inquiry into the facts is to be searching and careful, the ultimate standard of review is a narrow.one. The court is not empowered to sub- stitute its judgment for that of the agency.” Citizens to Preserve Overton Park v. Volpe, supra, at 416. The agency must articulate a “rational connection between the facts found and the choice’ made.” Burlington Truck Lines v. United States, 371 U.S. 156, 168 (1962). While we may not supply a rea- soned basis for the agency’s action that the agency itself has not given, SEC v. Chenery Corp., 332 US. 194, 196 (1947), we will uphold a decision of less than ideal clarity if the agency’s path may reason- ably be discerned. Colorado Interstate Gas Co., V. FPC, 324 U.S. 581, 595 (1945). Bowman Transportation, Inc. Vv. Arkansas-Best Freight System, Inc., 419 U.S. 281, 285-86 (1974). Undertaking the review called for concerning the issue in this case, we find that the agency took the following actions: 1) At a meeting of EPA Region V staff representatives on August 15, 1978, this court’s remand of the Pasquill- Gifford dispersion coefficients was considered. EPA there- after decided to continue to use the Class A coefficients “until an alternative approach is sufficiently demonstrated to. be more adequate.” 2) February 7, 1979, EPA published a Notice of Re- consideration in 44 Fed. Reg. 7,798 (1979), concerning 1) the use of Class A coefficients at the four power plants then concerned; and 2) extending the time necessary for compliance with emission limitations. 3) EPA also considered and rejected the solution pro- posed by appellants, namely, the use of Class B dispersion 8a coefficients “as contrary to both dispersion theory and available data.” It based the rejection in part upon data taken from studies at the Karlsruhe Nuclear Research Center in Germany. These studies, EPA found, supported use of the Class A coefficients. 4) A period followed when EPA received and con- sidered objections filed by the appellants claiming 1) in- applicability of the Karlsruhe data and EPA’s mis- interpretation of it; 2) EPA’s failure to consider all alternatives; and 3) its failure to take into proper ac- count “The enormous economic costs involved.” 5) On June 19, 1980, EPA announced and published its intention to continue to employ the Pasquill-Gifford Class A coefficients (See 45 Fed. Reg. 41,501 (1980) ). It subsequently denied appellants’ motions to reconsider. This court, of course, has no responsibility for deter- mining the merits (or lack thereof) of the technical ' standard EPA has adopted. Our duty ends when we are able to say that the agency has acted lawfully and that the decision is not “arbitrary, capricious or an abuse of discretion.” We find no violation of this standard on review of this record. The instant petitions for review are dismissed. : ee a ‘ — 9a UNITED STATES COURT OF APPEALS SIXTH CIRCUIT Nos. 76-2090, 77-1367, 76-2232, 77-1361, 76-2241, 77-1357, and 76-2278 CINNCINNATI GAS & ELECTRIC Co., COLUMBUS & SOUTH- ERN OHIO ELECTRIC Co., DAYTON POWER & LIGHT Co., OHIO EDISON Co., OHIO POWER Co., SHELL OIL Co., AUSTIN POWDER Co., E. I. du PONT de NEMOURS & Co., Petitioners, Vv. ENVIRONMENTAL PROTECTION AGENCY and DoucGLas M. CosTLE, ADMINISTRATOR OF THE ENVIRONMENTAL PRO- TECTION AGENCY, Respondents. Argued Oct 21, 1977 Decided June 29, 1978 Louis E. Tosi, C. Randolph Light, Fuller, Henry, Hodge & Snyder, Toledo, Ohio, Daniel W. Kemp, Cincinnati, Ohio, for Cincinnati Gas & Elec. Co., Shell Oil Co., et al. James Van Carson, Squire, Sanders & Dempsey, Cleve- land, Ohio, for Austin Powder Co. Carl B. Everett, Legal Dept., E. I. du Pont de Nemours & Co., Wilmington, Del., for E. I. du Pont de Nemours & Co. i ee ee i ee = —— - = 10a Ronald C. Hausmann, E.P.A., Paul M. Kaplow, Dept. of Justice, Washington, D.C., Mary Ann Muirhead, Region V, E.P.A., Chicago, Ill., Ned Williams, Director, Ohio E.P.A., Columbus, Ohio, for respondents. Before PHILLIPS, Chief Judge, and EDWARDS and PECK, Circuit Judges. EDWARDS, Circuit Judge. This opinion deals with certain additional issues pre- sented in 23 industry petitions covering 32 major power and industrial companies in Ohio objecting to the United States EPA’s plan for control of SO, pollution in Ohio. These additional issues concern only point sources of SO, pollution in Ohio’s rural areas or areas with complex terrain. This opinion should be read as supplementary to the opinion of this court dated February 13, 1978, Cleve- land Electric Illuminating Co., et al. v. Environmental Protection Agency, et al., 572 F.2d 1150 (6th Cir. 1978). Our focus herein is upon the following petitioners and the designated facilities belonging to them. These peti- tioners protest certain features of the United States EPA model (MAXT-24) employed for predicting plant pollu- tion in rural and complex terrain areas: .- Nos. 76-2090, 77-1367: Cincinnati Gas & Electric Co., all facilities (Hamil- ton & Clermont Counties). Columbus & Southern Ohio Electric Co., all facilities (Athens, Coshocton, Pickaway Counties). Dayton Power & Light Co., all facilities not covered by opinion dated February 13, 1978 (Adams County). Ohio Edison Co. (Jefferson County) Sammis Plant only. Ohio Power Co., all facilities (Washington and Mor- gan Counties). lla No. 76-2278: E. I. du Pont de Nemours & Co., all facilities (Hamil- ton County). Nos. 76-2282, 77-1361: Shell Oil Co., all facilities (Washington County). Nos. 76-2241, 77-1357: | Austin Powder Co., all facilities (Vinton County). The MAXT-24 model (Second Maximum 24-Hour Dis- persion Model with Terrain Adjustments) is designed for use in predicting SO, pollution resulting from single sources located in rural areas. Unlike the RAM model employed in urban areas, which we dealt with in Cleve- land Electric Illuminating Co., supra, MAXT-24 does not provide estimates of comparative contributions to total SO, pollution from a number of point sources. The MAXT-24 model treats each point source as an isolated problem, and only general background SO, pollution data are added into the formula. In other respects the MAXT-24 model strongly re- sembles the RAM model.* Thus, like RAM, MAXT-24 starts with a solid ascertainable data base, namely, the established design capacity of the power or steam gen- erating plants in question related to the sulfur content of the fuel used by such plants. Emissions data are developed from these factors. Subsequently, stack height, wind, weather, and terrain data are added. Like RAM, MAXT-24 employs a Gaussian plume formula and as- sumes vertical and horizontal dispersion of the pollution plume. It employs the Pasquill-Gifford stability classifi- cations and coefficients. Like RAM, the MAXT-24 model was designed by United States EPA largely as a result of industry criticism of 1 See Cleveland Electric Illuminating Co., supra, Section 3, 572 F.2d at 1160-64. , 12a the use of rollback modeling. As was true in relation to the RAM results, the results of use of MAXT-24 were generally less strict than those contemplated by the 1972 and 1974 Ohio EPA SO, regulations.” Indeed, the comments this court made in Cleveland | Electric Illuminating Co., supra, in Section 3 of the opinion are largely applicable to EPA’s adoption of MAXT-24 and we cite and rely on said Section 3 in hold- 2 The following summary is drawn from Cleveland Electric Il- luminating Co., supra, Appendix A, 572 F.2d at 1165-74: OhioEPA Ohio EPA US EPA 1976-77 1972 1974 MAX regs are: regs for: regs for: 1. less strict than 19 16 of petitioners’ facilities * stricter than 1 5 - ambiguous ” compared with 3 2 2. less strict than 31 27 of Ohio counties modeled entirely with MAX stricter than 3 * ambiguous ” compared with 5 6 es 3. less strict than 38 82 of Ohio counties in which MAX : was employed stricter than 3 6 7 ambiguous ” compared with 12 15 - *Including facilities to the regulation of which petitioners do not object. > /.e., stricter for some stacks or facilities and less strict for others; or employing different units of measurement, rendering comparison impossible. The 1972 Ohio EPA plan was submitted to United States EPA on January 30, 1972, but was “withdrawn” by the Gov- ernor of Ohio on August 27, 1972. The 1974 Ohio EPA plan was submitted to United States EPA on September 22, 1974, and was withdrawn on July 16, 1975. See Cleveland Electric Illuminating Co., supra. 572 F.2d at 1156. 13a ing that in general (and with one exception noted below) the EPA’s adoption and use of the MAXT-24 model is not arbitrary or capricious and, like the use of the RAM model, must be affirmed by this court. Despite the discussion above, we are not certain that any of the petitions we deal with in this opinion seriously disputes the general] validity of the MAXT-24 model. What these petitioners clearly do contend is that the MAXT-24 model results are badly skewed to their great economic disadvantage by 1) the Class A assumption em- ployed to estimate pollution dispersion in the least stable wind condition, and 2) the failure of EPA to employ the half ground displacement theory in estimating pollution impact on hillly terrain. I THE.CLASS A ASSUMPTION ISSUE The MAXT-24 model makes use of a set of six co- efficients for determining plume dispersal. The classes of coefficients employed were based upon six different weather conditions. The term Class A is employed to describe both the least stable weather condition and the set of assumptions which is based on the most direct and - quickest impact of the pollution plume upon ground level with the least prior dispersal. The six Pasquill-Gifford coefficients employed in MAXT- 24 are derived from a Nebraska study made in the 1950’s and are referred to by United States EPA as “time- tested” What this defense appears to ignore, however, is that petitioners in this instance (contrary to the general attack upon the six coefficients employed in RAM) are not objecting to the use of the coefficients; they are attack- ing the accuracy of one set of them—the Class A set associated with “gusty winds.” Specifically they claim that the Class A assumption is fallacious in that it as- sumes a longer period of downward draft than occurs in fact and fails to make allowance for the lateral dispersal which would accompany such a vertical wind at the point of impact. l4a The lead brief for the utilities presents the case thus: In all modeling of rural power plants, EPA utilized dispersion coefficients under Class A stability eondi- tions which have no support in data, which have been repudiated by most modelers and which are demon- strated inaccurate by this record. As applied to this rulemaking, this seemingly simple assumption is ex- ceedingly important because, for almost 1% of the power plants in Ohio, it was the determining factor in establishing emission limits. The meaning of “Class A.” Diffusion models can account for thousands of bits of data. Most important are meterological data of which stability classes are an aspect. Specifically, stability classes are categorizations of the atmosphere’s ability to disperse plumes. These classes are divided into six categories ranging from extreme dispersion of plumes (Class A) to minimum dispersion (Class F). Under Class A, a plume is assumed to disperse very rapidly to the ground level - before there is any substantial dilution. This, in turn, leads to predictions of high ground level con- centrations. The fundamental issue, therefore, is whether the Class A assumption describes the manner in which plumes disperse at rural power plants and whether the phenomena it depicts really occur. Brief of Utility Petitioners at 31-32 (emphasis in original). Petitioners then detail the results of three separate studies which they claim attack and undermine the va- lidity of the Class A coefficients, and generally urge substitution of Class B coefficients. These studies are the privately financed study by Environplan, Inc., a similarly produced study by Smith-Singer Meteorologists, SSE eS ee ee erhrh Oc lL 15a and a strongly critical report resulting from the Spe- cialists’ Conference of February 22-24, 1977, sponsored by United States EPA itself through the Argonne Na- tional Laboratory. To this argument the EPA’s response is as follows: EPA properly determined that the “Class A” sta-— bility factors should continue to be used until new field data proved them incorrect. Petitioners argue that EPA should have changed the dispersion coefficients used in the rural MAX (CRSTER) model for analyzing ground level con- centrations caused by a source in very unstable weather, known as “Class A” conditions. In the remand comment period, the utility petitioners pre- sented various theories that the model did not ac- ° curately reflect the way wind patterns in such weather conditions affect dispersion patterns and that therefore the model might be overestimating ground level concentrations for a 3-hour analysis. Petitioners argue that it was arbitrary or capricious for EPA not to accept theories presented in their comments. EPA recognized in the STSD [Supplemental Tech- nical Support Document] at 55 that there was a growing concern among atmospheric modeling scien- tists about the issue. EPA determined, however, that until further studies could be done to substanti- ate the theories, there was no experimental or field data to justify changing the dispersion curves or to determine how the dispersion equations should be changed. And since petitioners did not submit any data, no change could be made in the equations used. Id. EPA Brief at 48-49. 164 We are, of course, aware that decision-making (par- ticularly in this highly technical area) is the primary responsibility of the agency and not the responsibility of — this court. See Vermont Yankee Nuclear Power Corp. v. NRDC, 435 U.S. 519, 98 S.Ct. 1197, 55 L.Ed.2d 460 (1978). As we said in Cleveland Electric Illuminating Co., supra: Our standard of review of the actions of United States EPA is whether or not the action of the agency is “arbitrary, capricious, an abuse of discre- tion, or otherwise not in accordance with law.” Clean Air Act Amendments of 1977, Pub.L. No. 95- 95, §305(a), 91 Stat. 775 (to be codified as 42 U.S.C. § 7607(d) (9) (A)). Thus, we are required to affirm if there is a rational basis for the agency action and we are not “empowered to substitute [our] judgment for that of the agency.” Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402, 416 [91 S.Ct. 814, 28 L.Ed.2d 136] (1971). 572 F.2d at 1161. On this present record we conclude the United States EPA’s employment of the Class A assumption in deter- mining pollution dispersion under “least stable’ wind conditions in rural areas of complex terrain is not a rational decision and is arbitrary and capricious. As we read EPA’s position on this point, it is that no better solution has been proposed. This answer, however, ignores the Enviroplan and Smith-Singer studies. More importantly, it ignores the conclusions of the experts’ conference convened by Argonne National Laboratory at United States EPA’s own request.* The report of that * This conference was initiated by United States EPA and one of the participants was the Director of EPA Region V, which Region includes Ohio. The conference occurred during the remand Way conference suggested “elimination of the A curve and the use of the B curve for both A and B stability categories.” See Report of the Specialists’ Conference on the EPA Modeling Guideline, Feb. 22-24, 1977, Chicago, Illinois, at § 2.7.5: “Vertical Dispersion Estimates.” By pointing out this proposed solution, we do not man- date its acceptance by United. States EPA. Our ultima’e action on this score is simply to remand this issue to United States EPA for further study. This might result in the writing of a new record which supplies the now missing support for the use of Class A coefficients for the least stable wind condition in rural counties, or it might result in United States EPA’s adoption of use of the Class B coefficients for the two least stable wind conditions, or it might result in a new record which supports a wholly new solution. II THE TERRAIN ADJUSTMENT PROBLEM The original MAXT-24 model assumed that the pollu- tion plume moves downwind in a straight line from a point determined by the height of the smoke stack plus plume rise (“effective stack height”). Under that as- sumption, if effective stack height is 600 feet and there is a hill 800 feet high downwind, a receptor site located 600 feet up that ‘hill will therefore in theory receive the full impact of the pollutants in the center of the plume. Petitioners’ attack upon this set of assumptions is, we © believe, best stated by the Shell Oil Co. brief: The reference to “the effect of the terrain on the plume” is an easily understood concept. Since the wind which blows the plume toward a hill (terrain) period of this litigation, and three months before the finally amended regulations were promulgated. We consider the Confer- ence Report to be properly a part of the appellate record. 18a cannot blow through the hill, it must blow up and over the hill. This effect causes all the layers of air above the wind at ground level, and hence the plume itself, to be carried up and over the hill rather than hitting directly into its side. A widely recognized means of accounting for such a situation, and one which EPA has used, is to incorporate mathematical changes in the model which reduce the receptor height by the one-half difference between stack base and receptor elevation and limit the approach of the center line of the plume to ten meters above the receptor. Shell and its consultant, Enviroplan,, recommended this change to U.S. EPA. Moreover, this change was supported in the modeling literature by two other independent experts—Briggs and Egan. Also, another consultant, Environmental Research & Tech- nology, Inc. (“ERT”), recommended the same ad- justment in a report submitted to EPA during the comment period for Columbus & Southern Ohio Elec- tric Co. See “A Technical Review of the U.S. EPA Ohio State Implementation Plan for Sulfur Dioxide,” January 1977, prepared for C&SOE. (App. 210-213.) Indeed, this approach is so well recognized that EPA, Region II, approved its use in sustaining a revision of the implementation plan for Puerto Rico. See 40 Fed. Reg. 52410 (1975). Brief of Shell Oil Co., at 19-20.. As to this argument, the EPA brief contains this comment and admission: Contrary to petitioners’ claims, EPA utilized avail- able monitoring data wherever possible. As set forth in detail in both the Final and the Supplemental Technical Support Documents, EPA conducted valida- tion studies of the dispersion model used to set emission limitations for isolated, rural power plants. 19a See STSD at 53-55, and the FTSD at 27-34. The validation studies compared model predictions of SO. ground level concentrations to actual air quality monitor data. These comparisons indicated that for sources located on flat terrain, the correlation be- tween monitor data and predictions was quite good with the model tending to underpredict, but that for power plants located on hilly terrain, the compari- sons showed consistent overpredictions. EPA Brief at 45-46 (footnote omitted). The EPA brief then goes on to assert that cootain adjustments have been made in the model “so that it could handle dispersion in hilly terrain more accurately,” and then cited the Supplemental Technical Support Docu- ment at page 55. The STSD materiai referred to follows: The validation studies which compared model pre- dictions of SO, ground level concentrations to actual air quality monitor data indicated that in certain situations the model overpredicted and needed modi- fication. The problem usually occurred when air quality monitors were at elevations higher than the top of the stack. To correct this, terrain data used in the model was limited in such a way that terrain features were always assumed to be no higher than the stack height of the source stack in question. This was deemed to be an appropriate adjustment because the validation study showed a high degree of correlation between model’ predictions and sample readouts from monitors positioned on terrain. lower than stack height in elevation. When this assump- tion was mathematically incorporated into the model, the validation studies showed that the. model ac- curately predicted the ground level concentrations observed by the monitors. Petitioners proposed a different method for modi- fying the model to account for complex terrain situa- 20a tions, but the proposal is not based on any valida- tion studies of the CRSTER model. The Agency has no way of determining if the proposal is a better modification to the model than the modification made by the Agency after the validation studies. The Agency, therefore, has determined that the model does not need further modifications because of any information presented by the petitioners. EPA Brief at 54-55. While the record does not establish conclusively that this adjustment made by United States EPA in the re- mand period will prove a satisfactory solution to the problem posed, neither does the record offer evidence to the contrary. We note, of course, that United States EPA has disowned the apparent implication in its brief that it had made validation studies of this latest adjustment for hilly terrain. And, in fact, our holding on this issue should not be read as this court’s rejection of petitioners’ half ground displacement theory in favor of the United States EPA adjustment outlined above. There may well be occasion for the agency to continue to review this is- sue. All we hold is that on the present record, we can- not find that United States EPA’s present terrain ad- justment in MAXT-24 is “arbitrary or capricious.” For the reasons indicated above, the petitions of Day- ton Power & Light Co. (Adams County facilities only), Ohio Power Co. (all facilities), Columbus & Southern Ohio Electric Co. (Coshocton County facility only), and Austin Powder Co. (all facilities) are remanded to the United States EPA for reconsideration of the employ- ment of Class A coefficients in least stable wind condi- tions in rural counties. All petitions referred to at the beginning of this opin- ion are denied to the extent that they attack the MAXT- 24 model as to the terrain adjustment feature. 2la III OTHER ISSUES that there is no merit to objections based e to calibrate the MAXT-24 model (or failure to reject its results because of claims of overprediction as demonstrated by some monitor readings). See Cleveland Electric Illuminating Co., supra, 572 F.2d at 1163-64, numbered paragraph 7. Shell contends that its emission limitation should be expressed in terms of pounds SO, per hour rather than pounds SO, per million British Thermal Units. The Shell proposal would require the EPA either to assume that stack gas temperature and exit velocity (the impor- tant factors bearing on plume rise and thus ultimately on ground level SO, concentration) are relatively con- stant, or alternatively to monitor stack gas temperature and exit velocity. Clearly, EPA considers policing such a system to be an impossible task. EPA’s formula, by contrast, requires only the use of fixed, easily ascertain- able date—the plant’s design-rated capacity. We regard EPA’s choice of formula, which minimizes administra- tive costs while obeying the Clean Air Act’s command to “insure attainment and maintenance” of national am- bient air standards, 42 U.S.C. § 1857c-5(a) (2) (B) (1970),* to be within the range of the agency’s dis- cretion. We have considered the other issues raised by Shell and find them to be without merit. Disputes between petitioners and EPA concerning ap- propriate SO, background levels, emission data, or other fact issues will not be decided by this court until com- pletion of the administrative review of such issues which was suggested by this court and agreed upon by the parties. 4 Newly recodified at 42 U.S.C.A. § 7410(a) (2)(B) (1977 Pam- phlet) . 22a Based upon what has been said by this court in Cleve- land Electric Illuminating Co. v. EPA, supra, and in this opinion, and finding no other material issues, we dismiss the following petitions in toto: Cincinnati Gas & Electric Co:, Shell Oil Co. Final dispositions in the petitions of Columbia & South- ern Ohio Electric Co., Ohio Edison Co., and E. I. du Pont de Nemours & Co. will be entered on resolution of the remaining issues therein. 23a UNITED STATES COURT OF APPEALS SIXTH CIRCUIT Nos. 76-2090, 77-1367 THE CINCINNATI GAS AND ELECTRIC COMPANY, et al., Petitioners, V. ENVIRONMENTAL PROTECTION AGENCY and DouGLas M. CosTLe, Administrator of the ENVIRONMENTAL PROTECTION AGENCY, Respondents. June 29, 1978 Petition for Review of an Order of the Environmental Protection Agency Louis E. Tosi, C. Randolph Light, Fuller, Henry, Hodge & Snyder, Toledo, Ohio, Daniel W. Kemp, Cin- cinnati, Ohio, for petitioners. Ronald C. Hausmann, E.P.A., Paul Kaplow, Land and Natural Resources Div., Pollution Control Section, Dept. of Justice, Washington, D.C., Mary Ann Muirhead, Re- gion V, E.P.A., Chicago, Ill., for respondents. John W. Edwards, Lane, Alton & Horst, Columbus, Ohio, for amicus curiae Ohio Mining and Reclamation Ass’n. William W. Wehr, Freifield, Bruzzese, Wehr, Morland & England, LPA, Stuebenville, Ohio, for amicus curiae Ohio Coal Operators’ Ass’n, Inc. 24a William J. Brown, Atty. Gen. of Ohio, Environmental Law Section, David E. Northrop, Asst. Atty. Gen., Co- lumbus, Ohio, for intervenor, State of Ohio. Before PHILLIPS, Chief Judge, and EDWARDS and PECK, Circuit Judges. ORDER On receipt and consideration of a motion for clari- fication of this court’s opinion, dated February 13, 1978; and Believing that said opinion is self-explanatory, but un- derstanding petitioners’ desire for certainty, we reprint below the specific dispositive paragraphs of Cleveland Electric Illuminating Co. v. EPA, 572 F.2d 1150 (6th Cir. 1978) (Nos. 76-2090 et al.), numbered in sequence of their appearance in the opinion. 1) The cases dealt with in this opinion’ present the major general issues. Other individual cases, in ad- 1 This decision dismisses the objections to the regulations that apply to the following facilities : (a) Cleveland Electric Illuminating Co.—all facilities. (b) Dayton Power & Light Co.—Montgomery County facilities only. (ec) Ohio Edison Co.—Lorain County facilities only. (d) Toledo Edison Co.—all facilities. (e) The Timken Co.—all steam generating units. (f) White-Westinghouse Corp.—all facilities. (Although there was some confusion on this point in the briefs, the record makes clear that White-Westinghouse’s Franklin County facility is subject to the RAM model. See EPA Final Technical Support Document at IV-57.) (g) Standard Oil Co. of Ohio—Lucas County steam generating unite. ; (h) Interlake, Inc.—all steam generating units. (i) Coulton Chemical Corp.—all steam generating units. id., at 1152 (emphasis added). 25a dition to presenting one or more of the general issues, also present specific issues of fact. These are reserved pending a review of and reports on the factual dis- putes between the United States EPA and the in- © dividual petitioners. | 2) No other material issues are presented. 3) One petition pending before this court from the Northern Ohio Lung Association attacks United States EPA’s failure to promulgate a separate im- plementation plan for the “secondary standards” for the ambient air. This petition will be the subject of separate consideration. 4) Simliarly, this opinion does not govern any petitions where the RAM model waz not used. We do not de- cide any specific fact disputes raised by any petitioner as to plants other than those treated in this opinion.® Decision of these cases will follow. * See note 1, supra. 5) For the reasons stated above, the decision of the Ad- ministrator in imposing the SO, contro] plan is af- firmed subject to the reservations indicated above. Id., at 1165 (emphasis added). The petitioners’ Motion to Clarify, filed February 27, 1978, states accurately that this court’s opinion dis- posed of five issues, which it stated as follows: (1) The appropriateness of the use of RAM (raised in the joint RAM brief and incorporated by ref- erence in the utilities’ brief), (2) The claims for needed procedural safeguards of cross examination on remand (raised in the utility brief), (3) The economic and technical arguments (raised in the utilities’ brief), and 26a (4) The urban/rural designation issue (raised in the utilities, brief) . (5) The urban dispersion coefficients used in RAM (raised in the joint RAM brief). Subsequently, said petition lists the following five is- sues as unresolved: (1) Failure of U.S. EPA to utilize monitor data in regulation development (utilities’ brief), (2) Improper use of Class A Assumption in the rural model (utilities’ brief) , (3) Improper terrain adjustment features to the rural mode! ( utilities’ brief), (4) Failure of EPA to correct background and data errors (utilities’ brief), and (5) Invalidity of the plan for vagueness, and failure to consider sulfur-in-coal variability (utilities’ reply brief). Issues 2 and 3 are disposed of by this court’s opinion issued this date in Cincinnati Gas & Electric Co. v. EPA, 578 F.2d 660 (6th Cir. 1978). Issues numbered 1 and 5 above we deem disposed of by affirmance of EPA’s employment of the RAM and MAXT-24 models and the discussion in Cleveland Elec- tric Illuminating Co. v. EPA, and Cincinnati Gas & Elec- tric Co. v. EPA. Issue number 4 we consider to be fact questions which are subject to agreed-on administrative review. See Cin- cinnati Gas & Electric Co. v. EPA. For the information of these petitioners, and others, we call attention to the fact that by order dated Feb- ruary 9, 1978, the petition of the Northern Ohio Lung Association (No. 76-2282) was remanded to the United States EPA for further consideration. Northern Ohio 27a Lung Ass’n v. EPA, 572 F.2d 1182 (6th Cir. 1978). Additionally, as of today, an order is being entered deny- ing the petition of the Ohio Mining & Reclamation As- sociation and the Ohio Coal Operators’ Association, Inc. (No. 77-3290) because it seeks relief which can only be had from the Congress of the United States. As of this present date, this court considers that the United States EPA control plan for all Mahoning and Summit County facilities belonging to certain petitioners in these cases is under voluntary re-evaluation by United States EPA due to factual disputes. As these and other fact disputes are resolved, stipulations for dismissal! should be submitted promptly to this court. When factual disputes cannot be resolved, the parties should make every effort promptly to stipulate the disputed issues, or. failing that, to stipulate the opposing positions of the parties on the issue or issues. 28a [FRL 1579-5] RECONSIDERATION OF THE USE OF PASQUILL-GIFFORD DISPERSION COEFFICIENTS FOR STABILITY CLASS A IN SETTING EMISSION LIMITATIONS FOR FOUR OHIO POWER PLANTS; EVALUATIONS OF PUBLIC COMMENTS On February 7, 1979, the Environmental Protection Agency (EPA or the Agency) published a notice in the Federal Register soliciting public comment on the agen- cy’s reconsideration of the use of the Pasquill-Gifford (P-G) dispersion coefficients (or curve) for class A meteorological conditions in setting emission limitations for four Ohio power plants. 44 FR 7798. The agency published the notice in response to the decision of the United States Court of Appeals for the Sixth Circuit in Cincinnati Gas & Electric Co. v. EPA, 578 F. 2d 660 (1978). On June 29, 1978, the Court remanded to the Agency its decision to use the P-G dispersion coefficients for stability class A in modeling isolated rural power plants. The modeling had been performed by EPA to set emis- sion limitations for sources in Ohio to assure attainment and maintenance of the -national ambient air quality standards for the pollutant sulfur dioxide. See 41 FR 36324, 41 FR 52455, and 42 FR 27588. The Court found that the agency had not developed an adequate record to support the use of the P-G curve for class A conditions. Moreover, the Court held that the agency had not ade- quately considered an alternative to the use of the P-G class A curve proposed by the utilities during the rule- making. 1In the February 7, 1979 notice, EPA solicited comment on whether the four power plants whose emission limits were stayed by the agency’s reconsideration would need more time to come into compliance. The agency will propose new compliance schedules for those plants in a separate Federal Register notice. 29a In response to the Court’s decision, the agency recon- sidered the use of the P-G dispersion coefficients for class A conditions and evaluated the utilities’ proposal and the P-G class B dispersion coefficients be used in place of the class A dispersion coefficients. Based on field data not previously considered by the agency and current disper- sion theory, the agency found that the utilities’ proposal would severely underestimate ground level concentrations (44 FR 7798, February 7, 1979). Conversely, the agency found that dispersion theory and the Karlsruhe field data confirmed the agency’s use of the P-G class A dispersion coefficients in setting emission limitations to assure at- tainment and maintenance of the standards. The agency, therefore, concluded that it is reasonable to use the P-G class A curve to set emission limitations for the four power plants at issue.” Several utilities and utility consultants commented on the agecny’s proposed decision to continue to use the P-G class A dispersion coefficients. In general, commenters challenged the agency’s proposal by criticizing the Karls- ruhe field study data and continuing to argue that use of the P-G class A curve on modeling sources with ele- vated release points such as power plants will result in unrealistically high ground level concentrations at loca- tions unrealistically close to the source. However, in ad- dition to their original hypothesis that the sigma-z com- ponent of the P-G class A coefficients is too large, the utilities and their consultants also argued for the first time in their comments that the sigma-y component of the P-G class A curve is too smail. 2 EPA review of its rural modeling analysis identified four power plants where the class A conditions determined the emission limita- tions. The emission limitations for all other rural power plants in Ohio were not determined by class A conditions. The four plants are Stuart (Dayton Power & Light Co.) Conesville (Columbus and Southern Chio Electric Co.) Cardinal and Muskingum River (Ohio Power). 30a The utilities originally urged only one alternative to the P-G class A curve, namely to substitute the P-G class B curve for the P-G class A curve. See 44 FR 7798 (February 7, 1979). In response to the agency’s notice, commenters submitted new proposed alternatives to the P-G class A curve. Specifically, they urge the use of the Brookhaven class B, curve, the Julich class A curve, the Briggs curve, the F. B. Smith curve, the flutu- ating plume model, and the smaller averaging times method. Commenters also criticized the agency for not evaluat- ing actual air quality data available from power plant monitoring systems. In response to this, the agency re- viewed monitoring data from the John Sevier, Widows Creek, Cumberland, Muskingum River, Big Bend, East Bend, Conesville and Gibson power plants. The agency finds that the utility comments are with- out merit and that the utilities have not provided any technical basis to support changing the agency’s proposed finding. In fact, the monitor data which the utilities asked EPA te review support the agency’s determination that it should continue to use the P-G class A curve. Moreover, the data establish that all of the utilities’ pro- posals would underestimate maximum ground level con- centrations and therefore would not assure attainment and maintenance of the standards. In addition to the utility comments and data, the Agency reviewed the comments and recommendations of the Specialists’ Conference on the EPA Modeling Guide- line, ANL (1977), the American Meterological Society (AMS) Workshop on Stability Classification Schemes and Sigma Curves, Hanna et al. (1977), and the Na- tional Commission on Air Quality Atmospheric Disper- sion Modeling Panel, NCAQ (1980). These scientific groups recommended additional study of the effects of tall stack plume characteristics on ground level concentrations and the suitability of the P-G curves for tall stack sources. The Specialists Conference suggested that a pos- 3la sible result from such additional study “might include the: elimination of the A curve and the use of the B curve for both A and B stability categories.” See § 2.7.5 “Vertical Dispersion Estimates.”. The AMS Workshop, on the other hand, recommended the use of the Brook- haven curves, rather than the P-G curves, for elevated sources. The agency has studied the use of the P-G class A dis- persion coefficients and evaluated both suggested alterna- tives as part of its response to the Court’s remand. Based on EPA’s study, the agency has determined that the available data demonstrate that the P-G class A dis- person coefficients are reasnable means of setting emis- sion limitations that will assure attainment and main- tenance of the national air quality standards. In con- trast, the available data establish that the suggested al- ternatives underpredict ground level concentrations and therefore can not provide a means to set emission limita- tions adequate to assure attainment and maintenance of the standards. As stated in the February 7 notice, it is not the agen- cy’s contention that better methods of representing dis- persion should not be used when available and justified. 44 FR 7805. In fact, the agency continues to research this area. However, the agency has not yet developed a more accurate means for predicting ground level con- centrations near rural power plants during class A me- teorological conditions than the P-G class A dispersion _ coefficients. A. Original Utility Challenges, the Class B Alternative, and the EPA Proposal During the rulemaking on the sulfur dioxide emission limitations, the utilities contended that the P-G class A dispersion coefficients, which were developed from field studies of emissions released near ground level, were in- Eee a 32a appropriate for use in modeling power plants with tall stacks Specifically, the utilities hypothesized that -the P-G sigma-z values (controlling vertical dispersion) for class A conditions were too large for estimating ground level pollution concentrations caused by sources with tall stacks.* The utilities contended that use of the P-G class A sigma-z values for power plant modeling resulted in overpredicting ground level concentrations. However, as was explained’ in the February 7, 1979 notice, experimental research suggests that the sigma-z values should be as large or larger for elevated releases as compared to the sigma-z values for near ground level releases. See Panofsky (1978). Vogt, et al. (1978) and Weil (1978). Moreover, current dispersion theory is that sigma-z values for emissions over rough terrain should be equal to or larger than the sigma-z values for emis- sions over smooth terrain. See F.B. Smith (1973) and Pasquill (1974). 44 FR 7798. This is significant in that the original field experiments used to derive the P-G sigma-z values were conducted over prairie grass fields (relatively smooth terrain with a characteristic surface roughness length of less than 0:03 meters (m)) which are much smoother than the average terrain where the Ohio power plants are situated (surface roughness length is in the range of 1.0 m). In evaluating the utilities’ challenge to the class A sigma-z values and their recommendation of P-G class B, the agency reviewed the sigma-z values for the most 3 Each set of dispersion coefficients include a value representing the vertical dispersion of the pollutant (sigma-z value) and a value representing the horizontal dispersion (sigma-y value) in EPA’s CRSTER modeling each class of meteorological conditions is asso- ciated with a different set of dispersion coefficients Class A meteoro- logical conditions are the most unstable(very light and variable winds, clear sky and well developed mixing layer). Class B through F represent increasingly more stable atmospheric conditions. 33a unstable meteorological conditions which were determined by three different experimenters in three different dis- persion field studies. Table 1 in the February notice sets forth the sigma-z values derived by the Brookhaven, ' . Julich and Karlsruhe experiments. 44 FR 7800. Unlike the Pasquill-Gifford experiment, each of these experi- ments involved elevated releases of tracer (approximately 100 m) over terrain with surface roughness length of approximately 1.0 meters. These experiments, therefore, more closely approximated the elevated release points and terrain characteristics of the Ohio power plants. The comparison of sigma-z values from these three experiments with the sigma-z values in the P-G class A and B curves showed that under unstable meteorological conditions all three experiments measured sigma-z values larger than the sigma-z values associated with the P-G class B curve.* See Table 1, 44 FR 7800. The data dem- onstrate that use of the P-G class B curve as a substitute for class A would necessarily underpredict maximum ground level concentrations reached during class A con- ditions. Emission limitations based on the class B curve, therefore, would not assure attainment and maintenance of the standards. In short, without an analysis using the P-G class A dispersion coefficients, the agency would not be sure of setting emission limitations which would pro- tect the standards during periods of unstable meteorologi- cal conditions. In addition, the agency noted that the Karlsruhe field experiments determined sigma-z values during class A conditions as large or larger than the P-G class A sigma-z values. The Karlsruhe data therefore confirm the P-G class A sigma-z values and the resulting ground 4 The Brookhaven sigma-z values set forth in Table 1 are for BNL class B, meteorological conditions which are more stable than class A conditions. 44 Fed. Reg. 7800 Brookhaven experimenters did not derive sigma-z values for the most unstable stability class (class A). 34a level concentrations. The Karlsruhe experiments also con- firm the general locations of maximum ground level con- centrations predicted by using the P-G class A dispersion coefficients. 44 FR 7801. The agency therefore found that the Karlsruhe data supported the use of the P-G ‘class A dispersion coefficients in setting emission limita- tions for rural power plants. B.. Utility Comments on EPA’s Proposal : During the comment period, the utilities repeated their earlier contention that use of the P-G class A curve for rural power plants would result in model overprediction and overly stringent emission limitations. The utilities criticized the agency’s support for the use of the P-G class A curve and suggested other alternatives which like their original P-G class B proposal, would calculate lower maximum ground level concentrations than using the P-G class A dispersion coefficients. The utilities also urged the agency to review any available monitoring data recorded near power plants as a means of verifying the accuracy of the P-G class A dispersion coefficients. In response to this comment, the agency gathered the available monitoring data suggested by comments and reviewed it. Based on that review, the agency deter- mined that most of the available data is not relevant for evaluating the predictive accuracy of the P-G class A dispersion coefficients because of the placement of the monitors or because a supplementary control system was used. However, the agency did compare all of the rele- _ vant utility monitoring data with P-G class A modeling predictions. The agency found that actually measured sulfur dioxide concentrations during class A conditions are as high or higher than the maximum predictions cal- culated for the same monitor site using the P-G class A dispersion coefficients. Actual utility data, therefore, sup- ports the agency’s use of the P-G class A dispersion co- efficients for modeling power plants in rural areas. ee 35a 1. Utility Monitoring Data Agency review of power plant monitoring data as sug- gested by the commenters demonstrated that few of the monitors were located at distances less than 2 km from the source where maximum concentrations under class A meteorological conditions are expected to occur. EPA model anlyses using the P-G dispersion coefficients for the four Ohio power plants predicted maximum concentra- tions under class A conditions at distances 1.0 to 1.3 km from the plant.’ Therefore, to verify the accuracy of P-G class A model predictions, measurements from moni- tors located close to the source are required. The agency also found that several of the power plants having monitors within 2 km of their stacks use sup- plementary control systems.* This means that the plants reduce their emission rate during periods of expected high ground level pollution. An effective supplementary control system reduces ground level concentrauons that would otherwise occur under class A conditions without the use of such a system. Appropriate comparison of model predictions with monitor observations for these plants (where operating loads are reduced) requires the use of data reflecting the actual operation of the plants. Such data, including actual hourly emissions and stack effluent characteristics data and on-site meteorology, are not readily available. Each of the model analyses the agency has performed in evaluating available data has relied on maximum operating load and national weather service meteorological data. The agency, therefore, could not use the data influenced by the use of supplementary control systems to evaluate the predictive accuracy of the P-G class A curve. | 5 The Karlsruhe data confirmed that maximum concentrations under class A conditions occur within 1-5 km of the release point. 44 FR 7796. ? 6 The TVA plants at Widows Creek and Cumberland and the PSI Gibson plant use such systems. 36a Based on these considerations, the agency determined that data from two power plants—TVA’s John Seiver power plant and Ohio Power’s Muskingum River plant— could be used to evaluate the predictive accuracy of mod- eling with the P-G class A dispersion coefficients. See Table 2. In addition, the agency found that data from the monitoring system at the Muskingum River plant could be used to check the model’s prediction of the loca- tions of maximum concentrations under class A con- ditions. a. Accuracy of model predicted maximum concentra- tions using P-G class A dispersion coefficients.—In order to evaluate the accuracy of model predictions using the P-G dispersion coefficients for class A stability, the agency modeled the John Seiver ‘and Muskingum River power plants. The agency used the MPTER model with full load operating data provided by the power plants and at least six years of meteorological data.? The agency calculated the highest and second highest 3-hour ground level concentrations at the monitor sites for each year of meteorological data. See Table 3. The agency then com- pared these model predictions with the highest and second highest concentrations actually observed in a 3-hour pe- riod during each of monitor operation. This comparison showed that the monitors recorded maximum concentra- tions of sulfur dioxide as high or higher than the maxi- mum concentrations calculated by the model using the P-G class A dispersion coefficients. At John Sevier, the monitor has recorded sulfur di- oxide concentrations for six years. In four of the six years, the monitor recorded higher maximum concentra- tions than the model calculated for any of the six years of meteorological data.* Maximum levels of. 45, .40, .43, 8 Comparisons of monitor observations with model calculations using meteorological data for identical years were performed for 1973 and 1974 at the John Sevier monitor Meteorological data were not available for identical years to make such comparisons for addi- tional years. 87a .34, .28 and .17 ppm (parts per million) were actually recorded. See Table 3. The model using the P-G class A curve predicated a maximum of .32 ppm at the same lo- cation. Second highest maximum concentration levels of .39, .39, .31, .30, .22, and .15 ppm were recorded in the six years of monitoring compared to the highest model predicted second high maximum of .32 ppm. At Muskingum River, the monitor has recorded sulfur dioxide measurements for only two years. In those two years, the monitor measured maximum concentrations of .63 and .39 ppm, while the model calculated a maximum concentration of .55 ppm based on seven years of mete- orological data. The monitor recorded second high maxi- mum concentrations of .41 and .20 ppm, compared to the highest second high model prediction of .43 ppm. Actual power plant measurements, therefore, compare well with model calculations of maximum ground level concentrations using P-G class A dispersion coefficients. Moreover, the comparison establishes that the agency’s modeling using P-G class A curves does not predict un- realistically high concentraticns; rather, the agency’s modeling accurately predicts sulfur dioxide concentrations for class A meteorological conditions. b. Accuracy of model predicted locations of maximum ground level concentrations using P-G class A dispersion coefficients.—The agency’s modeling using the P-G class A dispersion coefficients predicted that maximum ground level concentrations would occur between 1 and 1.3 km from the source. Utilities challenged this contending that for elevated-sources maximum concentrations will occur further out from the-source. The utility monitoring data, however, confirm the P-G class A predictions. Data from the Muskingum River monitor system can be used to investigate the location of maximum concen- trations during class A meteorological conditions. At the Muskingum River plant, four of the six continuous SO, 38a monitors are located along a relatively straight line in a northeasterly direction from the plant. The monitors are located at distances of 1.7 km, 4.6 km, 8.5 km and 20.7 km from the plant along this radial. See Table 4. Review of the monitoring data shows that the highest 3- hour ground level concentration recorded by these moni- tors was observed at the monitor closest to the plant. See Table 5. Moreover, review of meteorological condi- tions during this period shows that the maximum con- centration occurred during class A conditions. In con- trast, the maximum impacts observed at monitors located further from the plant generally occurred during periods of more stable (greater cloud cover and/or higher wind speed) meteorological conditions. The Muskingum River data, therefore, establish that maximum concentrations do occur as close to the source as predicted by the model using the P-G dispersion co- efficients under class A conditions. Based on review of the utility monitoring data, the agency finds that model- ing with the P-G dispersion coefficients accurately pre- dicts the magniture and location of maximum ground level concentrations from power plants with tall stacks. 2. The Utility Challenge to the Karlsruhe Data As explained in the February 7, 1979 notice, the agency found that data from the Karlsruhe field experiments support the use of the class A dispersion coefficients. 44 CR 7801. The Karlsruhe field experiments as reported by Thomas et al. (1976) and Thomas and Nester (1976), measured ground level concentrations of two dispersion tracers, tritium (H,) and halogenated hydrocarbons (CCl,), released from 10 meter heights over terrain similar to the terrain surrounding the four Ohio power plants. Based on the measured ground level concentra- tions, sigma-z and sigma-y values were derived. Since the original utility challenge focused on the sigma-z values for the P-G class A curve, the agency compared 39a sigma-z values and found that the Karlsruhe experi- menters derived sigma-z values for class A conditions comparable to the P-G class A sigma-z values. See Table 1 and Figures 1-3, 44 FR 7800, 7800-8. The agency con- cluded that the Karlsruhe experimental data confirm the ‘general level and location of maximum ground level con- centrations predicted by using the P-G dispersion coeffi- cients (sigma-z and sigma-y) for class A meteorological conditions. See Figures 4-6, 44 FR 7803-4. The: utilities commented that the agency should not rely on the Karlsruhe data. They fault the Karlsruhe experiments for not using what the commenters contend are more advanced procedures and methodology in de- termining ground level concentrations and in deriving the dispersion coefficients. They commented that the Karlsruhe data are therefore suspect. However, com- menters did not point to any data to support their con- tention that the procedures actually used in the Karlsruhe experiments would result in unreliable data. On the contrary, as discussed above, utility monitors have actu- ally measured maximum concentrations as high or higher and as close to the source as predicted by the P-G class A dispersion coefficients. This monitor data confirm the Karlsruhe results as well as the use of the P-G class A dispersion coefficients. Moreover, additional Karlsruhe dispersion field studies reported in 1979 employed some of the experimental pro- cedures suggested by commenters and released tracer from 195 meters. This data confirmed the earlier Karls- ruhe results. Therefore, there is no basis for concluding that the Karlsruhe experimental procedures in any way “ In fact, the utility criticisms are contrary to their willingness to accept the results of the Brookhaven and Julich experiments or even the Pasquill-Gilford (for class B curves), all of which used experimental procedures similar to or less advanced than the Karisruhe procedures. 40a resulted in false measurements. See Kiefer and Koelzer (1979). Specifically, commenters criticized the Karlsruhe ex- periments for using non-bouyant tracer materials, a 100 meter release height, a manual sampling and collection system instead of an automated system, for analyzing air samples dissolved in toluene rather than directly sampling the air for measuring ground level concentrations and deriving .the sigma-z values from those measurements, rather than directly measuring sigma-z values, and for the mathematical analysis procedures chosen to derive the sigma-z and sigma-y values. Each of these criticisms is discussed below. a. Non-buoyant tracer and 100 m release height.— The utilities criticized the Karlsruhe experiments for using a non-bouyand tracer released at 100 m meters. The utilities point out that bouyant plumes, such as those released from power plant stacks, normally attain heights much higher than 100 meters (200-1,000 meters or more). The utilities commented that unstable tempera- ture gradients and building downwash would effect a non- buoyant tracer released at 100 meters, increasing the verticle dispersion of the tracer. Commenters argue that the vertical dispersion rates (sigma-z values) derived from the experiments would be too large for power plant plumes. However, the utility comment is contrary to both actual monitor data and dispersion theory. First, the utility monitor data demonstrate that under class A conditions, maximum concentrations as high or higher than calculated using the P-G class A curve and as close to the power plant as predicted by the P-G class A curve have been recorded. This data therefore confirm the use of the sigma-z values derived by the Karlsruhe experiments as well as the P-G class A sigma-z values. 4la Second, experimental research indicates that the verti- cal dispersion of power plant plumes increases with height. The rate of verticle dispersion of the plume does not decrease once the plume. rises to levels where the temperature gradients are more stable but rather remains constant or continues to increase. See Irwin (1979). The sigma-z values therefore should not be smaller for sources with elevated releases as compared to source releases near ground level. See also Panofsky (1978), Vogt et al. (1978), 44 FR 7799. a. Finally, the later Karlsruhe dispersion field studies, using a 195 meter release height, confirmed the large sigma-z values measured by the earlier Karlsruhe experi- ments and the P-G class A sigma-z values. In these later Karlsruhe experiments, tracer was released from 195 meters, a higher release point than used for any of the alternative curves proposed by the-utilities. See Table 1. The 195 m Karlsruhe experiments therefore are the most appropriate experimental work for evaluating dispersion coefficients for power plants. These later experiments measured vertical dispersion rates (sigma-z values) at distances greater than 1.3 km which were larger than the rates derived from the earlier 100 meter experiments. The data therefore contradicts the utility contention and support the earlier Karlsruhe results and the P-G class A sigma-z values. See Kiefer and Koelzer (1979). b. Manual sampling and collection system.—Comment- ers criticized the Karlsruhe experiments for using a manual sampling and collection system.. However, com- menters offer no data to show that an automated system would result in different measurements. In fact, the 1° Additional experimental studies were also conduced at 80, 100 and 160 meters. See Kiefer and Koelzer (1979). Results from the 195 m studies most closely approximate dispersion of pollutants from tall stack sources such as power plants. The agency therefore has relied upon the results of the 195 meter experiments in prefer- ence to the others. 42a later Karlsruhe field studies used an automated sampling and collection system and the results confirm the earlier Karlsruhe results. See Kiefer and Koelzer (1979). ce. Use of toluene in sample analysis —Commenters criticized the sample analysis method used by the Karls- ruhe experiments. Specifically, the commenters criticized the technique of dissolving the sampling in toluene before analysis and commented that a direct analysis would be more reliable. Commenters, however, do not demonstrate that direct analysis of the air sample would be more reliable than the technique used in Karlsruhe. ‘The use of toluene in the analysis technique is necessary in order’ to remove all of the tracer from the coilecting glass vessel and assure measurement of the entire sample. In fact, the methodology used by the Karlsruhe experimenters is an accepted experimental technique and there is no basis to conclude that it results in faulty data. d. Deriving sigma-z values from ground level concen- trations.—Commenters also criticized the Karlsruhe ex- perimenters for deriving the dispersion coefficients from ground level concentration measurements rather than making direct measurements of the sigma-y and sigma-z values. However, none of the dispersion field studies . reviewed by the agency, including Brookhaven and Julich, measured sigma-z and sigma-y values directly. Com- menters do not point to any dispersion studies which made direct measurements of sigma-y and sigma-z values under unstable conditions. It is simply too costly to make direct measurements under unstable meteorological con- ditions. Therefore investigators have traditionally de- rived the sigma-z and sigma-y values from ground level tracer concentration measurements. Commenters also failed to provide any data or theory to establish that direct measurements would lead to dif- ferent results. In short, while it might be preferable to determine dispersion coefficient values under very un- 43a stable conditions directly, as a practical matter, it is not done. e. Mathematical analysis procedures.—One commenter criticized the mathematical method the Karlsruhe experi- menters used to derive the sigma-y and sigma-z values. The Karlsruhe experimenters used a method of determin- ing dispersion coefficient values which smoothed out the variation in ground level concentrations expected under class A conditions. See Thomas and Nester (1978). The commenters applied two different mathematical methods to the Karlsruhe data and derivied smaller sigma-y values than the Karlsruhe experimenters. However, the com- menter chose methods which do not take into account the - expected variations in concentrations under class A con- ditions. Both the second moments and the cross-wind in- tegrated ground level concentrations methods are more appropriate for data sets with little variation. The in- appropriateness of these methods is confirmed by the commenter’s calculation of sigma-y values which de- creased with distance from the source. Such a result is contrary to the law of atmopheric physics that the hori- zontal distribution of a plume can not decrease with distance. f. Other comments on the Karlsruhe data.—Comment- ers made several other comments criticizing the Karlsruhe data, One commenter cited the fact that in experiment number 19.2, the Karlsruhe experimenters measured dif- ferent ground level concentrations of simultaneously re- leased tracers at co-located samplers. However, com- menters do not provide any data or theory to establish that the different measurements indicate faulty data. In fact, the 10-30 percent variation in sigma-z values derivied from these two measurements establish that the variations in concentrations was small. One commenter cited the fact that high background levels of the tracer were measured during time periods 44a when the experimenters indicated that the wind was not transporting tracer in the direction of the monitor. The commenter argues that this fact demonstrates the in- accuracy of the experimental sampling system. However, analysis of the cited time periods shows that while tracer was not transported directly to the sampling site, tracer materials were transported to the site by an indirect path resulting from the changing wind direction. Therefore, the tracer concentrations measured during these periods of changing wind direction are as would be expected and do not indicate any experimental inaccuracy. Another commenter criticized the Karlsruhe experi- ments because the distribution of crosswind concentra- tions for the individual experimentation periods did not fit perfect Gaussian curves and the maximum measured concentrations did not fall on a straight line from the tracer release point. Both of these criticisms assume un- realistic experimental results. Given the variations ex- pected in measurements made in a single experimentation period of 20 to 30 minutes, a perfect Gaussian distribu- tion is simply not expected. Moreover, given the chang- ing transport wind associated with class A meteorological conditions, maximum concentrations would not be ex- pected to follow a straight line. Rather, concentration measurements in a single experimentation period would be expected to vary from a perfect Gaussian curve and from a straight line from release point and this is ex- actly what happened. Another commenter criticized the Karlsruhe data be- cause some measurements fell outside the confidence limits specified by the experimenters. By definition, a percent-— age of the measurements are expected to fall outside the confidence limits. There is, however, no indication and the commenter does not establish that the number of . measurements falling outside confidence limits indicates that the experiments were deficient. 45a One commenter criticized the Karlsruhe data because the ratio of sigma-z values to sigma-y values is greater than one. The commenter contends that this indicates that the sigma-z values are too large. However, the com- menter does not support his assumption that this ratio should equal one for the unstable meteorological condi- tions associated with class A stability. Under the com- menter’s assumption, the vertical distribution of the plume would equal the horizontal distribution. However, under class A conditions greater vertical than horizontal turbu- . lence would be expected due to the convective forces associated with unstable meteorological conditions. There- fore, a ratio of sigma-z to sigma-y values which is greater than one would be expected and is exactly what was determined at Karlsruhe. One commenter used two different theories to calculate sigma-z values from.some of the Karlsruhe data. Again, the result was to derive smaller sigma-z values from the Karlsruhe data. The commenter based the derivation on the publications of Irwin (1979) and Smith (1968). Both Irwin and Smith have developed a relationship be-. tween the standard deviation of the wind elevation angle and the plume dispersion coefficients. The coramenter applied the theories to elevation angle data from the Karlsruhe experiments and derived smaller sigma-z values than the Karlsruhe experimenters derived from their measurements. However, the utility monitor- data dis- cussed above demonstrate that the sigma-z values derived by Karlsruhe and the P-G class A sigma-z values are not too large. In other words, use of smaller sigma-z values would conflict with actual monitor data. Another commenter used the Karlsruhe data to derive different dispersion coefficients than those derived by the Karlsruhe experimenters. The commenter used his ver- sion of the Karlsruhe dispersion coefficients to make a comparison with P-G class A and class B dispersion co- efficients. Mowever, the commenter does not explain or 46a support his reworking of the Karlsruhe data. In the February notice, the agency used the Karlsruhe disper- sion coefficients exactly as derived and reported by the Karlsruhe experimenters. Moreover, the utility monitor data confirms the Karlsruhe results. There is no reason to manipulate the Karlsruhe data and comparisons based on the manipulated data are inappropriate. | Commenters also criticized the agency for considering Karlsruhe experiment’ number 19.2 and not considering experiments number 19.1 and 19.3. Commenters contend that experiment number 19.2 was not conducted under class A conditions and that experiments number 19.1 and 19.3 were both class A experiments which should have been considered. In determining which experiments to consider as class A experiments, the agency used the classification of ex- periments set forth by the Karlsruhe experimenters. The Karlsruhe experimenters listed the class A experiments in Table 1, Thomas and Nester (1976). Experiment 19.2 was listed as class A based on the wind profile, even _ though the vertical wind fluctuation and temperature gradients fact [Text truncated at 120,000 characters. The full text is on the page linked above.] --- Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/brief%3Amicro_IA40385010_2577%3A1. Public record. Not legal advice.