Pursuant to Section 109 of the Clean Air Act (CAA), the EPA sets National Ambient Air Quality Standards (NAAQS) for certain pervasive air pollutants at levels "requisite to protect the public health" with "an adequate margin of safety." In 1997, EPA revised the ozone standard (moving to an 8-hour averaging time) and promulgated new fine particulate matter (PM2.5) standards, both more stringent than prior rules. Industry groups (including the American Trucking Associations) and a coalition of states petitioned for review in the D.C. Circuit, arguing principally that Section 109(b)(1) is an unconstitutional delegation because it gives EPA boundless discretion to set the stringency of NAAQS without a determinate principle, and that EPA was required to consider implementation costs when setting the standards. The D.C. Circuit concluded that, as interpreted by EPA, Section 109(b)(1) lacked a determinate principle and therefore presented a nondelegation problem; it remanded with instructions for EPA to develop a limiting construction that would meaningfully constrain its discretion. The court also held EPA could not consider costs when setting NAAQS. The Supreme Court granted certiorari.
1) Does Section 109(b)(1) of the Clean Air Act unconstitutionally delegate legislative power to the EPA by failing to provide an intelligible principle to guide standard-setting for NAAQS? 2) May EPA consider implementation costs when setting NAAQS under Section 109(b)(1)?
Nondelegation: Congress may delegate authority to agencies so long as it lays down an intelligible principle to guide the exercise of that discretion (J.W. Hampton, Jr., & Co. v. United States). A delegation is unconstitutional only if Congress provides no meaningful standard by which to confine and direct the agency's action. Statutory interpretation: Where a statute directs the agency to set standards "requisite to protect the public health" with an "adequate margin of safety," EPA may not consider implementation costs in setting those standards unless the statute clearly authorizes such consideration.
1) Section 109(b)(1) of the Clean Air Act provides an intelligible principle—standards "requisite to protect the public health" with an "adequate margin of safety"—and therefore is not an unconstitutional delegation of legislative power. 2) EPA may not consider implementation costs when setting NAAQS under Section 109(b)(1). The Supreme Court reversed the D.C. Circuit on nondelegation and affirmed on the no-costs holding, remanding for further proceedings consistent with its opinion.
Nondelegation. Writing for the Court, Justice Scalia reaffirmed that the nondelegation doctrine permits Congress to confer substantial policy discretion on agencies if Congress provides an intelligible principle to channel that discretion. Section 109(b)(1) directs EPA to set ambient air standards that are "requisite" (i.e., neither more nor less stringent than necessary) to protect public health and to include an adequate margin of safety to protect sensitive subpopulations. The Court emphasized that it has upheld far broader delegations using terms such as "public interest" or "fair and equitable," and that the CAA's health-based directive readily satisfies the intelligible principle standard. The Court rejected the D.C. Circuit's remedial approach instructing EPA to craft a determinate limiting principle to cure a perceived constitutional defect, explaining that if a statute truly lacks a constitutionally sufficient standard, an agency cannot supply it by administrative self-limitation. Any saving construction must come from Congress or from a fair judicial reading of the statute's text; it cannot be manufactured by the agency to validate an otherwise invalid delegation. Costs. On the separate question whether EPA may consider costs when setting NAAQS, the Court held it may not. Section 109(b)(1) speaks exclusively in health terms—protection of the public health with an adequate margin of safety—and contains no reference to cost. Elsewhere, the CAA expressly authorizes cost considerations in different contexts (e.g., technology-based standards, implementation measures, compliance deadlines), confirming by negative implication that Congress did not intend cost to factor into NAAQS stringency. The Court thus declined to read cost considerations into Section 109(b)(1), finding the text unambiguous. Because the statutory command is health-based, EPA's cost-blind approach was correct. Concurrences. Justice Thomas concurred in the judgment but questioned whether the Court's longstanding intelligible principle standard is faithful to Article I, suggesting that major policy decisions may be nondelegable and inviting future reconsideration of the doctrine. Justice Stevens (joined in part by Justice Souter) concurred, observing that setting ambient air standards is a legislative-type judgment that Congress permissibly assigned to EPA under the statute's health-based criterion, and he agreed that costs are excluded from NAAQS setting.
Whitman entrenches the modern, highly permissive intelligible principle test and demonstrates the Court's reluctance to revive robust nondelegation enforcement. It also establishes a critical statutory baseline in environmental law: NAAQS are health-based and cost-blind. For law students, Whitman is essential for three reasons: (1) It supplies the framework for evaluating nondelegation challenges and clarifies that an agency cannot cure an unconstitutional delegation by adopting its own limiting principle; (2) it exemplifies textual statutory interpretation that resists importing cost into a health-only mandate; and (3) it sets the stage for contemporary separation-of-powers debates, including the rise of the major questions doctrine as an alternative constraint on broad delegations, while Whitman remains the controlling articulation of nondelegation limits.
Whitman v. American Trucking reaffirms Congress's capacity to vest agencies with substantial discretion so long as Congress articulates a guiding principle. By reading Section 109(b)(1) to require health-based, cost-blind standards, the Court both preserved a central pillar of the Clean Air Act and reinforced the intelligible principle framework as the governing nondelegation standard.