Document ID: s3://data.kl3m.ai/documents/govinfo/USCOURTS/USCOURTS-caDC-96-01255/USCOURTS-caDC-96-01255-0/pdf.json

Parties Involved:
Carol M. Browner
Respondent
Environmental Defense Fund
Petitioner
Environmental Protection Agency
Respondent

Document Text:

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United States Court of Appeals

FOR THE DISTRICT OF COLUMBIA CIRCUIT

Argued September 26, 1997 Decided January 30, 1998 

No. 96-1251

AMERICAN LUNG ASSOCIATION, ET AL.,

PETITIONERS

v.

ENVIRONMENTAL PROTECTION AGENCY AND 

CAROL M. BROWNER, ADMINISTRATOR, UNITED STATES

ENVIRONMENTAL PROTECTION AGENCY,

RESPONDENTS

APPALACHIAN POWER COMPANY, ET AL.,

INTERVENORS

-

Consolidated with

No. 96-1255

-

On Petitions for Review of an Order of the 

Environmental Protection Agency

-

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Robert E. Yuhnke argued the cause for petitioners. With 

him on the briefs were Christine L. Shaver and Howard I. 

Fox.

Karen L. Egbert, Attorney, U.S. Department of Justice, 

argued the cause for respondents. With her on the brief 

were Lois J. Schiffer, Assistant Attorney General, and Michael L. Goo, Counsel, Environmental Protection Agency. 

Gerald K. Gleason, Counsel, entered an appearance.

Andrea Bear Field, Henry V. Nickel, Linda C. Trees, and 

James R. Bieke were on the brief for intervenor Appalachian 

Power Company, et al. Ross S. Antonson entered an appearance.

Before: EDWARDS, Chief Judge, GINSBURG and TATEL, 

Circuit Judges.

Opinion for the Court filed by Circuit Judge TATEL.

TATEL, Circuit Judge: On behalf of the nation's nearly nine 

million asthmatics, the American Lung Association and the 

Environmental Defense Fund challenge the Environmental 

Protection Agency's refusal to revise the primary national 

ambient air quality standards for sulfur dioxide 

(SO2). Declining to promulgate a more stringent national 

standard, the EPA Administrator concluded that the substantial physical effects experienced by some asthmatics from 

exposure to short-term, high-level SO2 bursts do not amount 

to a public health problem. Because the Administrator failed 

adequately to explain this conclusion, we remand for further 

elucidation.

I

Driven by its "deep concern for protection of the health of 

the American people," SEN. REP. NO. 91-1196, at 1 (1970) 

("SENATE REPORT"), Congress enacted the Clean Air Act 

Amendments of 1970, Pub. L. No. 91-604, 84 Stat. 1676 (1970) 

(codified as amended at 42 U.S.C. §§ 7401-7671q (1994)), 

mandating a "massive attack on air pollution," SENATE REPORT 

at 1. As amended, the Clean Air Act erects a comprehensive 

system of national ambient air quality standards ("NAAQS") 

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to regulate health-threatening air pollutants. The statute 

defines primary NAAQS as "ambient air quality standards 

the attainment and maintenance of which in the judgment of 

the Administrator, based on such criteria and allowing an 

adequate margin of safety, are requisite to protect the public 

health." 42 U.S.C. § 7409(b)(1).

Once the EPA Administrator concludes that a pollutant 

"may reasonably be anticipated to endanger public health or 

welfare" and that it comes from "numerous or diverse mobile 

or stationary sources," id. § 7408(a)(1)(A)-(B), the Act requires the Administrator to produce "criteria," defined as the 

latest scientific data on "all identifiable effects on public 

health" caused by that pollutant. Id. § 7408(a)(2). Based on 

these comprehensive criteria and taking account of the "preventative" and "precautionary" nature of the act, Lead Industries Ass'n, Inc. v. EPA, 647 F.2d 1130, 1155 (D.C. Cir. 1980), 

the Administrator must then decide what margin of safety 

will protect the public health from the pollutant's adverse 

effectsnot just known adverse effects, but those of scientific 

uncertainty or that "research has not yet uncovered." Id. at 

1153. Then, and without reference to cost or technological 

feasibility, the Administrator must promulgate national standards that limit emissions sufficiently to establish that margin 

of safety. See 42 U.S.C. § 7409(b)(1); American Petroleum 

Inst. v. Costle, 665 F.2d 1176, 1181-82 (D.C. Cir. 1981) 

(describing NAAQS promulgation procedure); Lead Industries, 647 F.2d at 1148-50 (in establishing NAAQS, Congress 

deliberately subordinated economic and technological feasibility concerns to the achievement of public health goals). 

States bear primary responsibility for attaining, maintaining, 

and enforcing these standards. See 42 U.S.C. § 7410.

In its effort to reduce air pollution, Congress defined public 

health broadly. NAAQS must protect not only average 

healthy individuals, but also "sensitive citizens"children, for 

example, or people with asthma, emphysema, or other conditions rendering them particularly vulnerable to air pollution. 

SENATE REPORT at 10; Lead Industries, 647 F.2d at 1152. If a 

pollutant adversely affects the health of these sensitive individuals, EPA must strengthen the entire national standard. 

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Lead Industries, 647 F.2d at 1153 (NAAQS "must be set at a 

level at which there is 'an absence of adverse effect' on [ ] 

sensitive individuals") (quoting SENATE REPORT at 10).

Sulfur Dioxide and Asthmatics

A highly reactive colorless gas smelling like rotten eggs, 

sulfur dioxide derives primarily from fossil fuel combustion. 

Best known for causing "acid rain," at elevated concentrations 

in the ambient air, SO2 also directly impairs human health. 

As the Administrator explains in the Final Decision on review 

here, at concentrations above 2.0 parts per million ("ppm"), 

SO2 can affect healthy nonasthmatic individuals; below 2.0 

ppm, it primarily affects people with asthma. National Ambient Air Quality Standards for Sulfur Oxides (Sulfur Dioxide)Final Decision, 61 Fed. Reg. 25,566, 25,570 (1996).

Following the passage of the Clean Air Act, EPA promulgated the SO2 NAAQS in effect today. The primary standards consist of a 24-hour standard (0.14 ppm averaged over 

24 hours not to be exceeded more than once a year) and an 

annual standard (0.03 ppm annual arithmetic mean). Id. at 

25,568. EPA also established a "secondary" three-hour standard (0.50 ppm averaged over three hours not to be exceeded 

more than once a year), designed to protect the "public 

welfare" against non-health-related effects such as visibility 

impairment or environmental degradation, see 42 U.S.C. 

§ 7409(b)(2). Petitioners do not challenge these existing 

standards.

Approximately four percent of the nation's population suffers from asthma. Characterized by bronchoconstriction

shortness of breath, coughing, wheezing, chest tightness, and 

sputum productionasthma is triggered by many different 

stimuli, including cold or dry air, exercise or pollen as well as 

airborne pollutants. The effects of bronchoconstriction can 

vary from short-term discomfort, such as an hour-long reaction with no lasting after-effects, to asthma attacks requiring 

medication or hospitalization. Although rare, death can result.

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Sulfur dioxide induces bronchoconstriction in asthmatics, 

but only under certain conditions. To experience adverse 

effects from SO2 concentrations below 1.0 ppm, asthmatics 

must be exposed for five minutes or longer while breathing 

quickly and heavily through both nose and mouth, the sort of 

breathing induced by light exercise, shoveling snow, climbing 

several flights of stairs, or jogging to catch a bus. At 

concentrations above 2.0 ppm, SO2 causes adverse effects 

even if the exposure lasts less than five minutes or the 

asthmatic breathes regularly. See Second Addendum to Air 

Quality Criteria for Particulate Matter and Sulfur Oxides 

(1982): Assessment of Newly Available Health Effects Information (1986).

The Challenged Final Decision

This case concerns the effect on asthmatics of what are 

known as high-level SO2 bursts, defined as emissions of 0.50 

ppm or more lasting at least five minutes. Occurring sporadically and from specific sources, SO2 bursts come primarily 

from power utilities; the rest come from nonutility sources 

such as industrial boilers, petroleum refineries, pulp and 

paper mills, sulfuric acid plants, and aluminum smelters.

Citing the health concerns of asthmatics and relying on a 

1977 amendment to the Clean Air Act, in which Congress 

ordered the Agency to review and revise all criteria and 

NAAQS by 1980 and at five-year intervals thereafter, 42 

U.S.C. § 7409(d), petitioners urged EPA to issue a new 

NAAQS limiting short-term SO2 bursts. Not until 1996, after 

petitioners sued twice to compel a decision, see Environmental Defense Fund v. Thomas, 870 F.2d 892 (2d Cir. 1989); 

American Lung Ass'n v. Browner, Civil Action No. 92-5316 

(E.D.N.Y. Nov. 12, 1992), and after two rounds of public 

notice and comment, did EPA issue its final decision regarding SO2 NAAQS. See NAAQS for Sulfur Oxides (Sulfur 

Dioxide)Reproposal, 59 Fed. Reg. 58,958 (1994); Proposed 

Decision Not To Revise the National Ambient Air Quality 

Standards for Sulfur Oxides (Sulfur Dioxide), 53 Fed. Reg. 

14,926 (1988). Rejecting petitioners' arguments, EPA conUSCA Case #96-1255 Document #327073 Filed: 01/30/1998 Page 5 of 11
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cluded not only that the annual and 24-hour primary standards needed no revision, but also that an additional fiveminute standard was unnecessary to protect asthmatics. See

Final Decision at 25,575-76.

In arriving at her final decision, the Administrator reviewed a decade of data on the extent of high-level short-term 

SO2 bursts and their effects on public health. See Review of 

the National Ambient Air Quality Standards for Sulfur Oxides: Assessment of Scientific and Technical Information: 

Supplement to the 1986 OAQPS Staff Paper Addendum (Sept. 

1994); Supplement to the Second Addendum (1986) to Air 

Quality Criteria for Particulate Matter and Sulfur Oxides 

(1982): Assessment of New Findings on Sulfur Dioxide Acute 

Exposure Health Effects in Asthmatic Individuals (Aug. 

1994). Based on clinical studies of mild to moderate asthmatics, she found that when such individuals breathe rapidly 

while exposed to SO2 concentrations of 0.60 ppm for five 

minutes, "substantial percentages ($ 25 percent)" experience 

effects "distinctly exceeding ... [the] typical daily variation in 

lung function" that asthmatics routinely experience. Final 

Decision at 25,572. The severity of these atypical effects, she 

found, "is likely to be of sufficient concern to cause disruption 

of ongoing activities, use of bronchodilator medication, and/or 

possible seeking of medical attention." Id. 

The scientific community disagreed about the medical significance of these effects and whether they should be considered "adverse." Some experts took the position that such 

symptoms usually have no lasting impact, amounting at worst 

to a brief period of reversible discomfort; others argued that 

even a one-hour disruption of activity can amount to a worrisome adverse health effect. The Administrator left this 

dispute unresolved. Instead, she discerned in the medical 

debate a consensus, which she adopted, that "repeated occurrences of such effects should be regarded as significant from 

a public health standpoint." Id. at 25,573 (emphasis added).

The Administrator then discussed the three exposure analyses on which the 1994 version of the proposed rule rested. 

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These studies estimated that from 180,000 to 395,000 "exposure events"defined as a heavily breathing asthmatic exposed to an SO2 burstoccur annually, affecting from 68,000 

to 166,000 asthmatic individuals. Id. at 25,574. In view of 

the Administrator's previous finding, reiterated by agency 

counsel at oral argument, that at least 25 percent of asthmatics experience atypical effects from exposure events, these 

data suggest that as many as 41,500 ($ 25 percent of 166,000) 

asthmatics experience atypical effects from repeated SO2

bursts each year. At the same time, the Administrator 

acknowledged that subsequent industry studies of four nonutility sources suggest that the 1994 studies may have overestimated exposure for certain SO2

sources, id., meaning that the 

number of affected asthmatics could be lower. The Administrator did not resolve the conflict between the studies.

Armed with all these data, the Administrator concluded 

that "the likelihood that asthmatic individuals will be exposed 

... is very low when viewed from a national perspective," 

that "5-minute peak SO2levels do not pose a broad public 

health problem when viewed from a national perspective," 

and that "short-term peak concentrations of SO2 do not 

constitute the type of ubiquitous public health problem for 

which establishing a NAAQS would be appropriate." Id. at 

25,575. Describing SO2 bursts as "localized, infrequent and 

site-specific," she concluded that a new national standard was 

unnecessary. Id. The Administrator nevertheless decided 

to encourage individual states to address short-term highlevel SO2 emissions, initiating a rulemaking to provide appropriate guidance. Proposed Implementation Requirements for 

Reduction of Sulfur Oxide (Sulfur Dioxide) Emissions, 62 

Fed. Reg. 210 (Jan. 2, 1997) ("Proposed State Guidelines 

Rulemaking") (soliciting public comment on proposed guidelines for state monitoring and regulation of five-minute peaks 

of SO2).

Petitioners now challenge the Administrator's decision declining to promulgate a new NAAQS. They assert that by 

failing to establish a five-minute NAAQS capping SO2 emissions at 0.60 ppm, EPA has violated its statutory responsibility to protect the public health. We review the Administrator's decision pursuant to 42 U.S.C. § 7607(d)(9)(A)-(C) 

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("[C]ourt may reverse any such [agency] action found to be 

... arbitrary, capricious, an abuse of discretion, or otherwise 

not in accordance with law; ... [or] in excess of statutory ... 

authority, or limitations....").

II

Petitioners challenge much of the data the Administrator 

relied on, as well as the conclusions she drew. Generally 

speaking, we will not second-guess EPA in its area of special 

expertise. See Natural Resources Defense Council v. United 

States EPA, 824 F.2d 1146, 1163 (D.C. Cir. 1987) (en banc); 

American Petroleum Institute, 665 F.2d at 1184. Applying 

this deferential standard of review, we accept the Administrator's analysis of the exposure studies in the record, as well as 

the implication of her analysisthat thousands of asthmatics 

can be expected to react atypically to SO2 bursts each year.

Petitioners contend that the Administrator's analysis 

amounts to a conclusive finding that SO2 bursts adversely 

affect asthmatics' health, thus triggering her duty to promulgate a new NAAQS. See Lead Industries, 647 F.2d at 1153. 

At oral argument, counsel for EPA vigorously disputed petitioners' contention that the Administrator "found" an adverse 

health effect. As we read the record, agency counsel appears 

to be correct: The Administrator did not decide whether 

asthmatic reaction to SO2 bursts"disruption of ongoing 

activities, use of bronchodilator medication, and/or possible 

seeking of medical attention"amounts to an adverse health 

effect or merely, as some medical experts argued, run-of-themill asthma symptoms indistinguishable from bronchodilation 

due to cold air or exercise. Final Decision at 25,572-73. 

Skipping this disputed question, the Administrator concluded 

that, regardless of the impact of single occurrences, "repeated 

occurrences of such effects should be regarded as significant 

from a public health standpoint." Id. at 25,573.

Disagreeing with this approach, petitioners argue that the 

Administrator had to answer the subsidiary "adverse effects" 

question, pointing to her warning to all states in the subseUSCA Case #96-1255 Document #327073 Filed: 01/30/1998 Page 8 of 11
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quent rulemaking that "[a]lthough these episodes are few, it 

is clear that 5-minute SO2 ambient concentration peaks pose 

a health threat to sensitive exposed populations," Proposed 

State Guidelines Rulemaking at 211. We need not decide 

that issue at this time, however, because we think the Administrator has failed to explain the answer she did give, i.e., that 

SO2 bursts do not amount to a "public health" problem within 

the meaning of the Act. The link between this conclusion and 

the factual record as interpreted by EPAthat "repeated" 

exposure is "significant" and that thousands of asthmatics are 

exposed more than once a yearis missing. Why is the fact 

that thousands of asthmatics can be expected to suffer atypical physical effects from repeated five-minute bursts of highlevel sulfur dioxide not a public health problem? Why are 

from 180,000 to 395,000 annual "exposure events" (the range 

indicated by the 1994 studies) or some fewer number (as 

suggested by the industry studies) so "infrequent" as to 

warrant no regulatory action? Why are disruptions of ongoing activities, use of medication, and hospitalization not "adverse health effects" for asthmatics? Answers to these questions appear nowhere in the administrative record.

In her only statement resembling an explanation for her 

conclusion that peak SO2 bursts present no public health 

hazard, the Administrator characterizes the bursts as "localized, infrequent and site-specific." Final Decision at 25,575. 

But nothing in the Final Decision explains why "localized," 

"site-specific" or even "infrequent" events might nevertheless 

create a public health problem, particularly since, in some 

sense, all pollution is local and site-specific, whether spewing 

from the tailpipes of millions of cars or a few offending smoke 

stacks. From the record, we know that at least six communities experience "repeated high 5-minute peaks greater than 

0.60 ppm SO2," id., and agency counsel told us at oral 

argument that these so-called "hot spots" are not the only 

places where repeated exposure occurs. Nowhere, however, 

does the Administrator explain why these data amount to no 

more than a "local" problem.

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Without answers to these questions, the Administrator 

cannot fulfill her responsibility under the Clean Air Act to 

establish NAAQS "requisite to protect the public health," 42 

U.S.C. § 7409(b)(1), nor can we review her decision. Judicial 

deference to decisions of administrative agencies like EPA 

rests on the fundamental premise that agencies engage in 

reasoned decision-making. See Vermont Yankee Nuclear 

Power Corp. v. Natural Resources Defense Council, 435 U.S. 

519, 524-25, 544-45, 558 (1978); SEC v. Chenery Corp., 332 

U.S. 194, 209 (1947) (agency's experience, appreciation of 

complexities and policies, and responsible treatment of the 

facts "justifies the use of the administrative process"). With 

its delicate balance of thorough record scrutiny and deference 

to agency expertise, judicial review can occur only when 

agencies explain their decisions with precision, for "[i]t will 

not do for a court to be compelled to guess at the theory 

underlying the agency's action...." SEC v. Chenery Corp., 

332 U.S. at 196-97. Where, as here, Congress has delegated 

to an administrative agency the critical task of assessing the 

public health and the power to make decisions of national 

import in which individuals' lives and welfare hang in the 

balance, that agency has the heaviest of obligations to explain 

and expose every step of its reasoning. For these compelling 

reasons, we have always required the Administrator to "cogently explain why [she] has exercised [her] discretion in a 

given manner." Motor Vehicle Mfrs. Ass'n v. State Farm 

Mut. Auto. Ins., 463 U.S. 29, 48 (1983).

In this case, the Administrator may well be within her 

authority to decide that 41,500 or some smaller number of 

exposed asthmatics do not amount to a public health problem 

warranting national protective regulation, or that three or six 

or twelve annual exposures present no cause for medical 

concern. But unless she describes the standard under which 

she has arrived at this conclusion, supported by a "[ ]plausible" explanation, id. at 43, we have no basis for exercising our 

responsibility to determine whether her decision is "arbitrary, 

capricious, an abuse of discretion, or otherwise not in accordance with law; ... [or] in excess of statutory ... authority, 

or limitations...." 42 U.S.C. § 7607(d)(9)(A)-(C).

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Given the gaps in the Final Decision's reasoning, we must 

remand this case to permit the Administrator to explain her 

conclusions more fully. We therefore need not resolve the 

debate between the parties over whether the Clean Air Act 

authorizes the Administrator to decline to protect an identifiable group of asthmatics from a known adverse health effect. 

Although our cases make clear that the Administrator has 

broad discretion to establish an "adequate margin of safety" 

above and beyond what scientific certainty prescribes and to 

craft regulations that protect against unknown harms, see 

Lead Industries, 647 F.2d at 1153-55 (Administrator must 

"err on the side of caution" when establishing the margin of 

safety, even where the "medical significance [of the effects] is 

a matter of disagreement"), they do not necessarily establish 

the converse propositionthat the Administrator may decline 

to establish a margin of safety in the face of documented 

adverse health effects. Since in this case the Administrator 

has failed adequately to explain her conclusion that no public 

health threat exists, we can leave the issue of the scope of her 

authority for another day.

We remand this case to the agency for further proceedings 

consistent with this opinion.

So ordered.

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