Order Code RS20228
Updated December 5, 2000
CRS Report for Congress
Received through the CRS Web
Clean Air Standards: The Supreme Court Agrees
to Review American Trucking Associations v. EPA
American Law Division
James E. McCarthy
Specialist in Environmental Policy
Resources, Science, and Industry Division
In 1999, in American Trucking Ass’ns, Inc. v. U.S. EPA, a U.S. Court of Appeals
ruled that deficiencies in EPA’s promulgation of revised national ambient air quality
standards for ozone and particulate matter required that they be remanded to the agency
for further consideration. The decision was controversial, in part because it relied on a
long-moribund legal principle known as the nondelegation doctrine. The court’s use of
this doctrine, if upheld, has implications for many delegations of congressional authority
to agencies. In addition, its holding that the revised ozone ambient standard cannot be
enforced has sparked debate. By itself, however, the decision is unlikely to have major
short-term effects on the ozone and particulate matter control programs.
In May, 2000, the Supreme Court agreed to review this decision, raising the
prospect of a major pronouncement on the nondelegation doctrine, the enforceability of
the revised ozone standard, and the role of compliance costs in setting nationwide air
In1999, the U.S. Court of Appeals for the D.C. Circuit ruled that deficiencies in
EPA’s promulgation of revised primary and secondary national ambient air quality
standards (NAAQSs) for ozone and particulate matter required that they be sent back to
the agency for further consideration. American Trucking Ass’ns, Inc. v. U.S. EPA, 175
F.3d 1027 (D.C. Cir.), modified on rehearing, 195 F.3d 4 (D.C. Cir. 1999), petition for
cert. granted, 120 S. Ct. 2003 (May 22, 2000), 120 S. Ct. 2193 (May 30, 2000). Given
the perceived impact of these clean-air standards on the economy, it was unsurprising that
the judicial challenges were brought in roughly 50 separate actions — with two Members
of Congress (Rep. Bliley and Sen. Hatch) filing as amici on the side of the challengers.
Congressional Research Service ˜ The Library of Congress
The controversy surrounding the court decision’s key rationale, resurrecting a longmoribund legal doctrine, echoed that surrounding the revised ozone and particulate matter
NAAQSs when they were promulgated in 1997.1
In May 2000, the Supreme Court agreed to decide certain issues raised in the D.C.
By way of background, NAAQSs lie at the very heart of the Clean Air Act (CAA).
These standards prescribe maximum pollutant concentrations for ground-level, outdoor
air, and have been promulgated by EPA for six pollutants.2 The NAAQSs determine the
stringency of emission limits that each state must impose on stationary air pollution
sources to achieve the NAAQSs within its borders. NAAQSs come in two forms:
“primary NAAQSs” protect the public health, while “secondary NAAQSs” protect the
public welfare (non-public health effects).3
What the D.C. Court of Appeals Said
The two-judge majority opinion. The most controversial portion of the majority
opinion is Part I, on unconstitutional delegation. This doctrine derives from Article I of
the Constitution, which vests “[a]ll legislative Powers” in Congress. Not surprisingly,
the Supreme Court eschews a literal reading of “[a]ll,” recognizing that Congress
routinely delegates quasi-legislative powers to non-Article I bodies. In particular,
Congress frequently commits to the specialized expertise of executive-branch agencies the
task of rulemaking in technical areas — such as air pollution control. The nondelegation
doctrine says that such delegations pass constitutional muster if Congress gives the agency
an intelligible principle to guide its exercise of that authority.
The majority found that EPA had construed CAA section 109 — requiring that
primary NAAQSs be set so as to “protect the public health” “allowing an adequate margin
of safety” — so loosely as to render it an unconstitutional delegation. The court agreed
with the factors used by the agency to assess the public health threat posed by air
pollutants. But, it said, EPA had articulated no intelligible principle for translating the
factors into a particular NAAQS, nor is one apparent from the statute.
Translating the impact factors into a numerical NAAQS requires more, insisted the
court, than asserting that a higher NAAQS would allow greater public health harm, and
a lower NAAQS less harm. This is always true for a nonthreshold pollutant,4 but does not
fix the maximum acceptable degree of harm. EPA also argued that at pollution levels
62 Fed. Reg. 38,652 (1997) (particulate matter NAAQS); 62 Fed. Reg. 38,856 (ozone
NAAQS). See generally John E. Blodgett, Larry B. Parker, and James E. McCarthy, Air Quality:
Background Analysis of EPA’s 1997 Ozone and Particulate Matter Standards (CRS Report 97-8
40 C.F.R. §§ 50.4-50.12.
CAA § 109(b); 42 U.S.C. § 7409(b).
According to the court, “EPA regards ozone definitely, and [particulate matter] likely, as
nonthreshold pollutants, i.e., ones that have a possibility of adverse health impact (however slight)
at any exposure level above zero.” 175 F.3d at 1034.
below the promulgated standard, health effects are less certain. The court rejected this
argument as well. “[T]he increasing uncertainty argument,” said the court, “is helpful
only if some principle reveals how much uncertainty is too much.”5
The court did not void the relevant CAA provision, but rather gave EPA an
opportunity to develop the constitutionally required intelligible principle. Such principle,
it opined, could not bring in compliance costs, since it has been judicially held that EPA
may not consider costs in setting primary NAAQSs. If EPA finds that no principle is
available, it would have to seek ratification of its NAAQSs by Congress.
Moving beyond the delegation issue, the court in Part II rejected petitioner arguments
that EPA had failed to consider various assertedly required factors in revising the
NAAQSs. For example, the court held that cost may not be considered in revising a
NAAQS, just as it may not be considered in setting the initial NAAQS.
In Parts III and IV, the court turned to arguments specific to particular NAAQSs.
Part III addressed the ozone NAAQS, holding that 1990 CAA amendments defining
“marginal” to “extreme” ozone nonattainment by resort to statutorily specified
atmospheric concentrations,6 did not by that fact bar EPA from revising the ozone
NAAQS. On the other hand, EPA is precluded from enforcing a revised primary ozone
NAAQS other than in accordance with the classifications, attainment dates, and control
measures set out in “subpart 2”: the act’s provisions dealing specifically with ozone
nonattainment.7 For this reason, the court declined to vacate the new ozone standards
while the agency, per the delegation-doctrine discussion above, seeks to divine an
The court also concluded that EPA must, in setting or revising a NAAQS, consider
the benefits as well as harmful effects of the pollutant. Thus, in addressing ozone, the
agency must weigh any protection from ultraviolet radiation by ground-level ozone. This,
said the court, the EPA may do on remand, assessing any such positive effects under the
“intelligible principle” that it may develop.
Part IV addresses the particulate matter (PM) NAAQSs. It opens by sustaining
EPA’s decision to regulate coarse particulate pollution (2.5 to 10 micrometers in diameter)
above the 1987 levels. Such coarse pollution, the court found, had documented health
effects apart from those of fine particulate matter (below 2.5 micrometers in diameter).
Still, the court held, EPA cannot deal with coarse particulate matter through a “PM10"
NAAQS that covers both coarse and fine particulates, since PM10 is an arbitrary indicator
for coarse particulate pollution. The PM10 NAAQS was therefore vacated.
Part IV also rejected an argument against the new PM2.5 NAAQS made by several
Midwestern (coal producing) states. They argued that because EPA is regulating fine
particulates separately for the first time, PM2.5 should be considered a new pollutant, with
all the CAA procedures that entails. The court saw it differently, viewing the PM2.5
Id. at 1036.
CAA § 181(a); 42 U.S.C. § 7511(a).
CAA §§ 181-185B; 42 U.S.C. §§ 7511- 7511f.
standard as merely a continuation of EPA’s trend, dictated by evolving science, toward
focusing PM controls on the most injurious part of the particle-size spectrum. Nonetheless,
because of its delegation doctrine holding, the court invited briefing on the question of
The one-judge dissent. The dissenting judge dealt exclusively with the delegation
issue, accusing the majority of “ignor[ing] the last half century of Supreme Court
nondelegation jurisprudence.” The NAAQS-setting section of the CAA, he believed, does
not give EPA unbridled discretion.
A later clarification. On petition for rehearing, the D.C. Circuit clarified some minor
aspects of its Part III ozone nonattainment discussion.8 It declined, however, to reconsider
its ruling on nondelegation.
The Supreme Court Takes the Case
On May 22, 2000, the Supreme Court granted EPA’s petition for certiorari. This was
unsurprising, since EPA challenged the D.C. Circuit’s controversial invocation of the
nondelegation doctrine. That use of the doctrine seemed vulnerable, based as it was on
the majority opinion’s assertion that EPA discretion to set primary NAAQSs under CAA
section 109 is without bounds. On the contrary, section 109 appears to impose at least a
partial, if not complete, constraint on EPA -- that primary NAAQSs be based on “air
quality criteria” published by the agency, and be set so as to “protect the public health”
allowing an “adequate margin of safety.”9 As the dissent noted, the Supreme Court has
sustained against nondelegation-doctrine challenge statutes instructing the FCC to regulate
broadcast licensing “in the public interest,”10 authorizing the Price Administrator to set
“fair and equitable” prices,11 and empowering the Attorney General to regulate drugs that
pose an “imminent hazard to public safety.”12 If these vague standards are constitutionally
adequate constraints on agency discretion, then arguably the CAA’s bounds on the setting
of primary NAAQSs are as well.
Indeed, except for two Depression-era cases in which standards were found to be
absent, the Court has never found constitutional fault with a congressional delegation.13
All that the Court seems to insist on (sometimes) is that Congress employ a delegation
which “sufficiently marks the field within which the Administrator is to act so that it may
195 F.3d 4, 10 (D.C. Cir. 1999).
CAA § 109(b)(1); 42 U.S.C. § 7409(b)(1).
National Broadcasting Co. v. United States, 319 U.S. 190 (1943).
Yakus v. United States, 321 U.S. 414, 426-427 (1944).
Touby v. United States, 500 U.S. 160 (1991).
See Mistretta v. United States, 488 U.S. 361, 371-379 (1989) (reviewing case law). It
should be noted that American Trucking Associations does not target the congressional delegation
itself, as did previous delegation decisions. Rather, it implicitly recognizes that agencies can cure
delegation deficiencies in statutes, thus transforming the delegation doctrine into a requirement that
agencies constrain their own discretion.
be known whether he has kept within it in compliance with the legislative will.”14 Where
the congressional standard is combined with requirements of notice and hearing and
agency statements of findings and considerations, so that judicial review under due process
standards is possible, the constitutional requirements of delegation have been fulfilled.15
The judicial review provisions of the CAA arguably satisfy this lax standard.16
The D.C. Circuit decision on nondelegation, if left intact by the Supreme Court,
means that all future new and revised NAAQSs are presumably subject to challenge on
nondelegation grounds — unless, of course, the agency follows some judicially approved
“intelligible principle” developed in the current litigation.17 Beyond this, any Supreme
Court endorsement of a reborn nondelegation doctrine could have implications for federal
environmental regulation generally — indeed, for many non-environmental delegations of
congressional authority to agencies.
A second important issue raised in EPA’s petition related to the “subpart 2"
discussion above. EPA’s petition asks whether provisions of the 1990 CAA amendments
specifically aimed at achieving ozone attainment, such as subpart 2, restrict EPA’s general
authority under other CAA provisions to implement new and more protective NAAQSs.
While the Supreme Court’s grant of EPA’s petition was expected, its grant of the
industry’s, on May 30, 2000, was not. The industry petition asked whether the CAA
requires EPA, when setting primary NAAQSs, to ignore factors other than health effects
– such as costs of compliance. The petition proposed that a negative answer to this
question might allow EPA to supply an “intelligible principle” satisfying the nondelegation
doctrine. That compliance costs cannot be considered in the setting of primary NAAQSs
had long been considered a settled matter, ever since a 1980 decision of the D.C. Circuit.
The Supreme Court heard oral argument on both petitions on November 7, 2000.
Congress has functioned primarily as an interested observer while the appeals process
runs its course, but it has taken two steps, in legislation enacted October 27, 2000, to
ensure that EPA would not implement any aspect of the new standards prior to a final
court decision. The first of these steps18 prohibits EPA from designating nonattainment
areas under the new ozone standard (and possibly imposing new permit requirements on
major sources of air pollution in such areas) until June 15, 2001 or until the Supreme
Court’s decision, whichever occurs first. In a separate amendment, the bill delayed for a
Yakus, 321 U.S. at 425.
Id. at 426.
CAA § 307(d); 42 U.S.C. § 7607(d).
Nondelegation challenges to existing NAAQSs would seemingly be time barred. CAA
section 307(b)(1) instructs that petitions for review of primary and secondary NAAQSs must be
filed within 60 days after notice of promulgation appears in the Federal Register. 42 U.S.C. §
H. Amdt 859 to H.R. 4635, the VA-HUD-Independent Agencies Appropriation for FY
year the imposition of requirements that transportation projects in new nonattainment
areas conform to an area’s plan to attain clean air standards.19
Because the schedule for implementation of new NAAQS standards is lengthy, and
because other provisions of the Act are unrelated to the setting of a NAAQS, the delays
caused by congressional action and court challenges have had little effect to date. Without
court intervention, EPA would have had until July 2000 to promulgate a list of ozone
nonattainment areas under the 8-hour standard and until December 2005 to designate
PM2.5 areas. State implementation plans for those nonattainment areas would not have
been due until 2003 and 2008, respectively. The ozone deadlines have clearly been
delayed by the appeal process, but the monitoring to identify nonattainment areas has gone
forward; if EPA prevails, it will be ready to proceed with designation of ozone
nonattainment areas upon the resolution of court challenges. The PM2.5 deadlines are so
far in the future that they may not be affected, unless the standards are overturned by the
Meanwhile, other sections of the Act that are unaffected by decisions regarding the
NAAQSs are driving continued improvements in air quality, and will force major sectors
of the economy to implement more stringent emission controls. These include Phase II of
the Acid Rain program under Title IV of the CAA, Tier 2 auto emission standards under
section 202, the hazardous air pollutant program under section 112, new standards for
diesel engines under Title 2, and the regional haze program under section 169.
Ultimately, no matter what the outcome of American Trucking Associations,
Congress may choose to address the issue of congressional delegation of authority to set
NAAQSs. The language of section 109, requiring protection of public health with an
adequate margin of safety but providing no further "intelligible principle" by which EPA
should make such a determination, is reminiscent of the original language of section 112
of the CAA governing hazardous air pollutants (HAPs). Between 1970 and 1990, EPA
had great difficulty setting standards under that section, since it seemed to imply that
emissions of nonthreshold pollutants should not be allowed at all. After years of court
challenges to EPA attempts at regulation, Congress, in the 1990 CAA amendments,
enacted a completely different approach to regulating HAPs: a list of pollutants was
identified in the statute, and EPA was directed to promulgate emission standards for
sources of these pollutants that embodied the Maximum Achievable Control Technology
(MACT), a term defined with great specificity in the Act. Later, the Agency is to examine
residual risks remaining after the imposition of MACT; here, too, Congress was specific
in establishing a standard by which to judge the need for regulation ( a 1-in-a-million
cancer risk). Section 109 presents similar issues and might be susceptible to a similar
solution. Whether Congress will address this issue is likely to depend on the outcome of
EPA's and industry’s appeals in American Trucking Associations, however.
Conference Report on H.R. 4635 (H.Rept. 106-988), Title III, Environmental Protection
Agency, Administrative Provisions, p. 46.