Before BAZELON, Senior Circuit Judge, and WALD and MIKVA, Circuit Judges. Opinion for the Court filed by Senior Circuit Judge BAZELON.
UNITED STATES COURT OF APPEALS, DISTRICT OF COLUMBIA CIRCUIT
Nos. 79-1708 to 79-1711 1981.CDC.200
Petitions For Review of Orders of the Environmental Protection agency.
DECISION OF THE COURT DELIVERED BY THE HONORABLE JUDGE BAZELON
In 1971, pursuant to the Clean Air Amendments of 1970, Pub.L.No. 91-604, 84 Stat. 1679, the Administrator of the Environmental Protection Agency promulgated a series of national ambient air quality standards, known as the NAAQS, for sulfur oxides. The standards established maximum acceptable average concentrations for one-year periods, 24-hour periods, and 3-hour periods. Under the Act and the EPA regulations, if the outdoor air of a locality exceeds either the 24-hour or 3-hour standard more than once during a year, construction of new pollution sources would be restricted and existing sources could be restricted in the technology they may employ.
Prior to 1979, compliance with the 24-hour NAAQS for sulfur oxides, 40 C.F.R. § 50.4(b), was generally determined by analyzing daily average concentrations based on air samples collected during midnight-to-midnight periods. In 1979, however, pursuant to section 110 of the Clean Air Act, as amended, 42 U.S.C. § 7410(a)(2)(Supp. III 1979), the Administrator promulgated a new rule which implemented a national air quality monitoring system. *fn1 In promulgating the rule, EPA purported to require the new monitoring system to measure sulfur oxide concentrations continuously and to calculate hourly running averages for 24-hour periods, rather than only midnight-to-midnight averages. The use of running averages would reveal whether concentrations of sulfur oxides exceed the NAAQS level for any 24-hour period during the year, whereas midnight-to-midnight measurement would only reveal exceedances for 365 specific 24-hour periods. Depending on the times of the day at which sulfur oxide concentrations reach their high and low points, a locality with concentrations that exceed the level set by the standard for many 24-hour periods would be detected by the running average technique but would escape detection under the midnight-to-midnight sampling method.
These appeals challenge the 1979 rule that requires the running average technique for measuring sulfur oxide concentrations. Petitioners operate major stationary sources of sulfur dioxide. They would face significant economic burdens if the air monitoring statistics showed their localities to be in violation of the NAAQS for sulfur oxides. Petitioners charge that the challenged rule, in effect, revises the 24-hour NAAQS for sulfur oxides, and that it therefore should have been promulgated according to the exacting procedures set forth in section 307(d) of the Clean Air Act, 42 U.S.C. § 7607(d) (Supp. III 1979). Respondent argues that the rule does not constitute a revision of the NAAQS, but merely establishes closer and more uniform air quality monitoring, as mandated by section 319, 42 U.S.C. § 7619 (Supp. III 1979). Therefore, respondent contends, the agency properly proceeded by informal rulemaking, 5 U.S.C. § 553 (1976).
The scope of review, as well as the lawfulness of EPA procedures, depends upon the characterization of the agency's action. If the rule effects a revision of the NAAQS, then its adoption would require the procedures set out in § 7607(d), which are more demanding than those of the Administrative Procedure Act . At the same time, however, 7607(d) would preclude our invalidation of the rule on procedural grounds without a much stronger showing of prejudicial error than is required in cases under the APA. *fn2 If, on the other hand, the rule does not effect a revision of the NAAQS, then it would have to be adopted only according to the APA procedures.
To decide whether the agency's action amounts to a revision of the 24-hour NAAQS for sulfur oxides, this court must resolve a fundamental ambiguity in the meaning of the NAAQS itself. The question, explained more fully below, is whether an exceedance of the standard's "maximum 24-hour concentration" can be computed on the basis of all periods of twenty-four consecutive hours ("running averages"), or whether it must be computed on the basis of midnight-to-midnight periods only. Unfortunately, EPA has complied no administrative record directed toward that issue. Petitioners were apparently caught off-guard because of the obscurity of the notice given. They claim they were unaware that this issue was presented in the challenged rulemaking, and so offered no comments at all. We thus find ourselves in a "catch-22": the agency's procedures have produced no visible basis upon which to review its interpretation of the 24-hour NAAQS; yet, without reviewing that interpretation, we cannot determine the adequacy of its procedures. We, therefore, must examine the 24-hour sulfur oxide NAAQS directly, but only to the extent necessary to determine whether EPA's interpretation was not wholly unreasonable.
We conclude that the 24-hour NAAQS does not require a midnight-to-midnight sampling period, and that the new rule, therefore, does not revise that standard. Therefore, EPA's rulemaking proceeding under the APA, rather than the Clean Air Act, was not facially unlawful. We also find, however, that EPA failed to publish a critical provision of the new rule in the Federal Register and thereby violated the publication requirement of the APA. Belated publication cannot cure this omission. Because the proposed rule did not notify the public that the use of running averages was being proposed and because that proposal was an important aspect of the rule, EPA failed to comply with the notice requirement of the APA in its attempt to mandate the use of running averages. We therefore remand the record to the EPA to consider that part of the rule, after proper notice, by whatever procedures are adequate to develop a proper record for decision. Further, we admonish the parties that an important interpretation of an agency standard must, in the first instance and in clear fashion, be carried out by the agency itself, with review by the court following only upon an adequate record. I. BACKGROUND
Congress has been concerned with air pollution for over a quarter of a century. See Act of July 14, 1955, Pub.L.No.84-159, 69 Stat. 322. In 1970, it enacted sweeping changes in the Clean Air Act. *fn3 The amendments directed EPA's Administrator to promulgate NAAQS and provided for the adoption of state plans to achieve and maintain those standards. The "primary" NAAQS prescribe maximum acceptable concentrations of various pollutants in the outdoor air which, "allowing an adequate margin of safety, are requisite to protect the public health." 42 U.S.C. 7409(b)(1). The "secondary" NAAQS prescribe levels "requisite to protect the public welfare from any known or anticipated adverse effects." Id. 7409(b)(2). These standards function as benchmarks for the state implementation plans. The statute provides that both the primary and secondary NAAQS be based on "air quality criteria" for each pollutant, which
accurately reflect the latest scientific knowledge useful in indicating the kind and extent of all identifiable effects on public health or welfare which may be expected from the presence of such pollutant in the ambient air, in varying quantities.
The NAAQS at issue here concerns sulfur oxides, measured as sulfur dioxide. Sulfur dioxide contributes importantly to the scope and severity of the nation's air pollution problem. It is emitted in large quantities when industrial or public utility power plants burn high sulfur fossil fuels, especially coal. *fn4 In the atmosphere, it is converted to sulfur trioxide, sulfuric acid, and salts of sulfuric acid. J.A. 459. Acute episodes of sulfur dioxide pollution, especially in connection with high levels of particulate matter, result in increased mortality and morbidity. In the world's most disastrous incident, about 4000 excess deaths were attributed to the smog that struck London in December 1952. Typically the elderly and persons with pre-existing pulmonary and cardiac disease are the most susceptible. J.A. 566-67. Significant health effects are also produced by long-term exposure to sulfur dioxide pollution:
Acute respiratory infections in children, chronic respiratory diseases in adults, and decreased levels of ventilatory lung function in both children and adults have been found to be related to concentrations of SO2 and particulates ....
Rall, Review of the Health Effects of Sulfur Oxides, 8 Env'tal Health Perspectives 97, 99 (1974), quoted in Republic Steel Corp. v. Costle, 621 F.2d 797, 800 (6th Cir. 1980). Finally, atmospheres polluted with oxides of sulfur are believed to attack and damage a wide range of materials ...