Tag: Clean Air Act

Ninth Circuit Upholds EIS for Southern California Delivery of Colorado River Water

The Imperial County Air Pollution Control District and the County of Imperial challenged the United States Department of the Interior’s Environmental Impact Statement analyzing the effects of water transfer agreements on the Salton Sea and in southern California. The court held that the Department did not violate NEPA or the Clean Air Act. The case is People of the State of California ex rel. Imperial County Air Pollution Control District v. U.S. Department of the Interior (May 19, 2014) 14 C.D.O.S. 5454.


The Salton Sea’s access to Colorado River water—the Sea’s only water supply— is in jeopardy. In 1922, states in the Colorado River basin agreed to divide the river’s water among the upper- and lower-basin states. In 1931, southern California irrigation and water districts agreed to a framework for distributing the state’s share of the river water, which assumed a perpetual surplus of the water. In 1963, the Supreme Court held in Arizona v. California that California’s Colorado River allotment was limited to 4.4 million acre-feet per year, and that the state could only exceed this limit if other lower-basin states did not use their allotments or there was a surplus of water. In 1999, several water districts negotiated Quantification Settlement Agreements to reduce Colorado River water usage.

In 2001, the Secretary of the Interior announced that she would prepare an Implementation Agreement EIS to consider the consequences of delivering a portion of Imperial Irrigation water at different diversion points on the Colorado River for use outside of the Imperial Valley. The Final EIS (“FEIS”) discussed on-river environmental impacts of altering Colorado River delivery diversion points, indirect effects of changing the amount of water received by the California districts, and potential mitigation measures to reduce off-river ecological consequences. In 2003, the Secretary evaluated minor modifications to the proposed master implementation agreement, the Colorado River Water Delivery Agreement. She determined a supplemental EIS was unnecessary and issued a final record of decision. Plaintiffs sued and the district court granted summary judgment to the defendants, holding that plaintiffs lacked standing and, alternatively, rejecting their NEPA claims on the merits.

Ninth Circuit Decision

The Ninth Circuit Court of Appeal held that plaintiffs had established Article III standing, and thus moved on to plaintiffs’ substantive arguments. In assessing plaintiffs’ NEPA claims, the court first considered whether the Secretary had taken a “hard look” at the environmental consequences of the proposed action and reasonably evaluated the relevant facts.

Plaintiffs argued that the Implementation EIS either did not clarify whether it incorporated the state Transfer Environmental Impact Report or the Federal Transfer EIS, or improperly cited to a non-NEPA document—the Transfer EIR. The court determined that plaintiffs’ assertion that the FEIS cited to the separate CEQA and NEPA reviews as if they were a single document was “fly-specking,” and the court stated it would not let a minor misstatement prejudice its review. The court also found harmless a reference to a document as “tiered to and incorporated” when the analysis should have only said “incorporated.” The court further held that the Secretary did not act arbitrarily by separately preparing a Transfer EIS and an Implementation Agreement EIS, since the project could be properly segmented in that manner under the independent utility test.

The court held that the Secretary did not abuse her discretion in concluding that a supplemental EIS was unnecessary. The changes contained in the FEIS: (1) were qualitatively considered through a no-mitigation alternative; (2) were a secondary aspect of the EIS; (3) reduced overall an adverse environmental impact; and (4) did not alter the project’s cost-benefit analysis. Additionally, the FEIS and the record of decision sufficiently considered potential mitigation measures.

The court also held that the decision to discuss only one alternative—no action—was not arbitrary and capricious. NEPA does not require discussion of a minimum number of alternatives; the number depends on the stated goal of the project. The FEIS compared the project to only one alternative because the project was a negotiated agreement. Discussing a hypothetical alternative that no one had agreed to or would likely agree to, the court reasoned, would have been unhelpful.

The court also found the EIS sufficiently discussed air quality, reclamation, and growth-inducing impacts.

Finally, the court addressed plaintiffs’ Clean Air Act claims. The court noted that neither federal nor state conformity rules (which prohibit the authorization of activities that do not conform with an approved implementation plan) identify the form an agency must use when deciding whether a project necessitates a full-scale conformity determination. Here, the Secretary announced her decision that a conformity determination was unnecessary in the FEIS. The court stated that an agency need not prepare a stand-alone document explaining that decision. Furthermore, the Secretary did not abuse her discretion by concluding that Interior Department actions would not directly cause PM10 emissions. The project only committed the Secretary to changing the delivery point of Colorado River Water; any actions would occur at dams far from those diversion points.

The court affirmed the judgment of the district court.

U.S. Supreme Court Rules the EPA Has Authority Under Good Neighbor Provision of Clean Air Act to Establish Rules Limiting Emissions and Curtailing Air Pollution Emitted in Upwind States

Environmental Protection Agency et al. v. EME Homer City Generation, L.P., et al. (2014) __U.S.__ (April 29, 2014, Case no. 12-1182)

Over the past several decades, Congress and the Environmental Protection Agency (EPA) have made several efforts to address the difficult challenge of curtailing air pollution emitted in upwind states, but causing harm in downwind states. Under the Clean Air Act, the EPA must establish national ambient air quality standards (NAAQS) for pollutants at levels that will protect health. Once the EPA establishes a NAAQS, it must designate “nonattainment” areas—locations where pollution concentration exceeds the NAAQS. Within three years of any new or revised NAAQS, each state must submit a State Implementation Plan (SIP) to achieve the NAAQS. If the EPA determines a SIP is inadequate, it must prepare and adopt a Federal Implementation Plan (FIP). Among other things, the SIP must “contain adequate provisions … prohibiting … any source or other type of emissions activity within the State from emitting any air pollutant in amounts which will … contribute significantly to nonattainment in, or interfere with maintenance by, any other State with respect to any … [NAAQS].” (42 U.S.C. § 7410 (a)(2)(D)(i).) This requirement is known as the “Good Neighbor Provision” of the Clean Air Act.

Many times over the past two decades, the EPA has attempted to delineate the Good Neighbor Provision’s scope by identifying under what circumstances an upwind state can be said to “contribute significantly” to nonattainment in downwind states. One such attempt is the EPA’s Cross-State Air Pollution Rule (Transport Rule), which aims to reduce mono-nitrogen oxides (NOx) and sulfur dioxide (SO2) emissions in 27 upwind states to achieve attainment of three NAAQS in downwind states. Under the Transport Rule, an upwind state “contribute[s] significantly” to downwind nonattainment if its exported pollution: (1) produces one percent or more of a NAAQS in at least one downwind state; and (2) could be eliminated cost-effectively, as determined by the EPA. Upwind states whose emissions meet both these criteria must eliminate their emissions. Based on complex modeling, the EPA also created an annual emission “budget” for each of the regulated upwind states, representing the total quantity of pollution an upwind state may produce in a given year under the Transport Rule. Having determined that each of the regulated upwind states’ SIPs was inadequate, the EPA also adopted FIPs concurrently with its adoption of the Transport Rule.

A group of state and local governments, joined by industry and labor groups, petitioned for review of the Transport Rule in the D.C. Circuit. The Court of Appeal vacated the rule in its entirety, holding that: (1) the EPA must give states a reasonable opportunity to allocate their emission budgets before issuing the FIPs; and (2) the EPA must not consider cost in determining whether an upwind state “contribute[s] significantly” to a downwind state’s nonattainment. In an opinion delivered by Justice Ginsburg, in which Justices Roberts, Kennedy, Breyer, Sotomayor, and Kagan joined, the Supreme Court reversed.

First, the Court held that the Clean Air Act does not require the EPA to give states a second chance to file a SIP after the EPA has quantified the state’s interstate pollution obligations. Although the state respondents in the case did not challenge EPA’s disapproval of any particular SIP, they argued that the EPA is nevertheless required to give upwind states an additional opportunity to promulgate adequate SIPs after the EPA has set the state’s emission budgets. The Court found that the Clean Air Act’s plain text does not support this argument. Rather, the Clean Air Act only requires that once the EPA disapproves of a SIP, the EPA must issue a FIP. Although the EPA had previously provided upwind states an opportunity to allocate emission budgets among their in-state sources, this did not mean that the EPA acted arbitrarily in declining to do so here.

Second, the Court held that EPA’s cost-effective allocation of emission reductions among upwind states is a permissible, workable, and equitable interpretation of the Good Neighbor Provision. The Court noted that the Good Neighbor Provision does not dictate a specific method of apportioning responsibility among the upwind contributors. In the absence of specific guidance, the EPA’s use of costs in the Transport Rule is an efficient and equitable solution to the allocation problem presented by the Good Neighbor Provision. Furthermore, contrary to the D.C. Circuit’s holding, the EPA must have leeway in fulfilling its mandate to maximize achievement of attainment in downwind states.

U.S. Supreme Court Takes Up the Issue of Greenhouse Gas Emissions Regulation in Coalition for Responsible Regulation v. EPA

On October 15, 2013, the U.S. Supreme Court granted certiorari in Coalition for Responsible Regulation v. EPA (2012) 684 F.3d 102. It is regarded as the most important federal case involving greenhouse gas emissions after its predecessor, Massachusetts v. EPA (2007) 549 U.S. 497.


The case below involved a number of the U.S. EPA’s Clean Air Act rules regulating greenhouse gas emissions from stationary sources, such as large industrial plants, refineries, and factories. A three-judge panel of the United States Court of Appeals for the D.C. Circuit unanimously upheld the EPA’s rules in June 2012. Specifically, the court upheld the EPA’s endangerment finding for greenhouse gases and the agency’s decision that the endangerment finding made greenhouse gases an “air pollutant” for purposes of the Prevention of Significant Deterioration (PSD) program. The court also held that plaintiffs lacked standing to challenge how the rule is phased in.

Various interest groups and states submitted a total of nine petitions for certiorari, seeking to overturn the D.C. Circuit’s decision. The Supreme Court accepted six of these petitions.

The Court will consider the narrow issue of whether the EPA acted within its authority in determining that its regulation of greenhouse gas emissions from new motor vehicles triggered permitting requirements for stationary sources under the Clean Air Act. This means that the Court will leave some of the lower court’s findings undisturbed, including the endangerment finding and the “tailpipe rule,” which sets emissions standards for automobiles.


The challenged Clean Air Act provisions are the “timing” and “tailoring” rules, which together exempt small stationary sources from the greenhouse gas regulations that would otherwise apply. As enacted, the Act regulates every “source” of greenhouse gases emitting 100 tons of a single pollutant, including homes, apartment buildings, and small businesses. The EPA determined that regulating every source at that emission level would be both impractical and politically unpopular, so it created the tailoring rule to confine application of the Act to new sources emitting at least 100,000 tons of greenhouse gases per year and modifications of existing sources that increase emissions by 75,000 tons.

The industries and states challenging the tailoring rule argue that the rule is unlawful, since it relieves sources emitting between 100 and 100,000 tons from regulation when the statute clearly says those sources must be regulated. They also argue that the PSD provisions of the Act under which the EPA is regulating the larger emitters do not apply to greenhouse gases. The challengers believe the PSD provisions only apply to those pollutants on the National Ambient Air Quality Standards’ criteria pollutants list, which does not include greenhouse gases.

The criteria pollutant list is selective; it contains only six air pollutants which have a demonstrable effect on human health, such as lead and carbon monoxide. However, after the Court held that greenhouse gases are air pollutants under the Clean Air Act in the 2007 case Massachusetts v. EPA, the EPA found six greenhouse gases that must be regulated due to their threat to public health and welfare. Thus, though greenhouse gases are not technically listed as a criteria air pollutant, they have been found to be dangerous to human health. In fact, the PSD already applies to non-criteria pollutants, albeit more obscure ones like sulfuric acid mist. Plus, the EPA’s interpretation of its own statutes will be accorded significant deference under Chevron, which makes the challengers’ position an uphill battle.

The lower court never reached the substance of the challengers’ arguments because it found that they did not have standing, reasoning that regulating larger businesses while exempting smaller ones did not injure the larger businesses. In fact, the Court found that the tailoring rule could even help states like Texas – one of the states challenging the rule – because it would lessen the state’s burden in administering the Clean Air Act permitting program.

A ruling on the statutory interpretation issues could help to clear some of the ambiguities plaguing the Clean Air Act, which has not been amended since 1990. With the increasing national and international focus on climate change, environmentalists and industry alike would benefit from more guidance on how the Act applies to greenhouse gases. The Court will hear arguments in early 2014 and is anticipated to issue a ruling by July.

Second District Court of Appeal Upholds South Coast Air Quality Management District’s Rule Limiting Volatile Organic Compounds in Paint Thinners and Solvents against Challenge that the Rule Is Preempted; Rejects Claim that CEQA Required District to Analyze Alternatives to the Rule

On June 28, 2012, in W.M. Barr & Company Inc. v. South Coast Air Quality Management District ___Cal.App.4th___ (Case No. B233892), the Second District Court of Appeal upheld the South Coast Air Quality Management District’s Rule 1143, which requires manufacturers of consumer paint thinner and solvent products to limit the use of Volatile Organic Compounds (VOCs) in their products in order to meet the District’s obligations under the federal Clean Air Act and the California Clean Air Act.

In July 2010, the District adopted Rule 1143. The District believed that Rule 1143 would cause manufacturers to replace the VOCs with acetone, a highly flammable solvent. The District therefore prepared an environmental assessment under CEQA evaluating the fire hazard risks of substituting acetone and proposing specific product labeling to alert consumers.
W.M. Barr & Company, Inc. (Barr), a manufacturer of paint thinners and solvents, challenged Rule 1143 on the grounds that (1) Rule 1143 was preempted by the Federal Hazardous Substance Act (FHSA); (2) Rule 1143 was preempted by regulations simultaneously adopted by the California State Air Resources Control Board (the Board); and (3) the District did not comply with CEQA because it failed to consider alternatives to the measures it adopted. The trial court rejected each of these claims and the Court of Appeal affirmed.

First, the Court of Appeal found that Rule 1143 was not federally preempted. Barr argued that the FHSA preempts Rule 1143 because Rule 1143 requires products to include a “hang-tag” stating that the product has been formulated to meet low VOC standard and to have warnings on the label. According to Barr, the hang-tag requirement addresses the same fire risks as the FHSA, which includes requirements for fire warning labels, and therefore the FHSA preempts the rule’s hang-tag requirement. The Court of Appeal rejected this argument for two reasons. First, the language of the FHSA, which covers “directions for use,” does not expressly preempt the hang-tag because Rule 1143’s hang-tag requirement only requires the hang-tag to instruct users to see the product’s warning label, rather than containing specific directions for use under federal labeling requirements. Second, while Rule 1143 ostensibly addresses “increased fire hazards,” the hang-tag does not directly address fire hazards. Instead, the primary (and narrower) risk the hang-tag addresses is the risk the user will not be familiar with the hazards of the product because it has been reformulated to comply with Rule 1143. The broader question of fire risk is secondary to Rule 1143, and remains governed by the FHSA. Therefore, the court concluded, the FHSA did not preempt Rule 1143’s hang-tag requirement.

Next, the court considered whether state law preempts Rule 1143 and concluded it does not. Barr argued that under California Health and Safety Code section 41712, subdivision (f), Rule 1143 is preempted by the Board’s general purpose regulation of cleaning products, which bars the District from adopting a regulation for a consumer product for which the Board has already adopted a regulation. Barr asserted that because the Board had adopted a regulation for general purpose cleaners, Rule 1143 conflicted with this regulation and was therefore preempted. The court disagreed, explaining that Health and Safety Code section 41712, subdivision (f) states: “[a] district shall adopt no regulation pertaining to disinfectants, nor any regulation pertaining to a consumer project that is different than any regulation adopted by the state board for that purpose.” The court found that the phrase “any regulation already adopted by the state board for that purpose” implicitly refers to regulations already adopted by the Board. This language is clear: if the Board has not yet adopted a regulation in the area, an air management district would not, by definition, be able to adopt a regulation that was different. Here, the Board’s regulations governing paint thinners and multi-purpose solvents were enacted after Rule 1143, not before. Therefore, the court held that Rule 1143 was not preempted by state law.

Finally, the court considered Barr’s CEQA claim. Under CEQA, the District’s adoption, amendment or repeal of a District rule is a certified regulatory program. Certified regulatory programs are considered functionally equivalent to the preparation of an EIR or negative declaration and therefore, in lieu of an EIR or negative declaration, agencies may prepare a substitute environmental review document. In the case of the District, the substitute document is what the District terms an “environmental assessment.” Barr argued the District’s environmental assessment for Rule 1143, which functioned as a mitigated negative declaration, violated CEQA because it failed to consider feasible alternatives. The court rejected this argument because, as a functional equivalent to a mitigated negative declaration, the environmental assessment was not required to analyze feasible project alternatives. Substantial evidence supported the District’s conclusion that Rule 1143 would not cause any significant environmental impacts. Therefore, the District was not required to analyze or make findings regarding alternatives to Rule 1143. (by Laura Harris)

D.C. Circuit Court of Appeals upholds EPA’s Greenhouse Gas Regulations

On June 26, 2012, in Coalition for Responsible Regulation, Inc., et al., v. Environmental Protection Agency, No. 09-1322 (D.C. Cir. June 26, 2012), the D.C. Circuit Court of Appeals upheld the Environmental Protection Agency’s Endangerment Finding and Tailpipe Rule regarding greenhouse gases. The court also upheld the agency’s interpretation of the Clean Air Act (CAA) requiring major stationary sources of greenhouses gases to obtain construction and operating permits. Opponents of these rules disputed the Endangerment Findings and EPA’s authority to regulate GHG emissions under the CAA based upon the finding.

Background and Procedure

The EPA promulgated the disputed rules following the Supreme Court’s holding in Massachusetts v. EPA that GHGs may be regulated as an air pollutant under the CAA. In response to this holding, the EPA first issued its Endangerment Finding for GHGs. The Finding was based “on a considerable body of scientific evidence,” and EPA concluded that emissions of specified GHGs “contribute to the total greenhouse gas air pollution, and thus to the climate change problem, which is reasonably anticipated to endanger public health and welfare.” Based on this finding, the EPA was required under the CAA to establish motor-vehicle emission standards for GHGs. The ensuing Tailpipe Rule set GHG emission standards for cars and light trucks as part of a joint rule-making with fuel economy standards issued by the National Highway Traffic Safety Administration.

Due to EPA’s standing interpretation of the CAA, the Tailpipe Rule automatically triggered regulation of stationary GHG emitters under the Prevention of Significant Deterioration of Air Quality (PSD) program and Title V. The PSD program requires state-issued construction permits for stationary sources producing either 100 tons per year (tpy) or 250 tpy of any air pollutant. Title V requires state-issued operating permits for stationary sources that have the potential to emit at least 100 tpy of any air pollutant. EPA then issued two rules phasing in stationary source GHG regulation. First, in the Timing Rule, EPA concluded that an air pollutant becomes subject to regulation under the CAA (and therefore to PSD and Title V) only once a regulation requiring control of that pollutant takes effect. Therefore, EPA determined major stationary emitters of GHGs would be subject to PSD and Title V permitting requirements on the date the Tailpipe Rule became effective—or the date when GHGs first became regulated under the CAA. Following the Timing Rule, EPA promulgated the Tailoring Rule, providing that only the largest sources of GHG emissions, those exceeding 75,000 or 100,000 tpy CO2e, would initially be subject to the GHG permitting. This rule was adopted after the EPA determined requiring permitting for all sources would be overwhelmingly burdensome for both permitting authorities and stationary sources.

A number of states and regulated industries filed petitions for review of these new GHG regulations, arguing the EPA misinterpreted the CAA or otherwise acted arbitrarily and capriciously.

Challenges to the Endangerment Finding.

Petitioners challenged EPA’s Endangerment Finding on numerous substantive and procedural grounds. All challenges were rejected by the court.

  1. EPA’s interpretation of CAA section 202(a)(1).

Petitioners argued that the EPA improperly interpreted CAA § 202(a)(1) as restricting the finding to a science-based judgment without considerations of policy concerns and regulatory consequences. Petitioners believed the EPA was required to consider the benefits of activities emitting GHGs, the effectiveness of emissions regulation, and the potential for societal adaptation to or mitigation of climate change. Petitioners argued that, by not considering these factors, EPA acted arbitrarily and capriciously.

The Court determined the plain language of CAA § 202(a)(1) was contrary to these arguments. The language of the section requires only that the endangerment evaluation relate to whether an air pollutant causes or contributes to air pollution which may reasonably be anticipated to endanger the public health or welfare. The court held that the evaluation process required “scientific judgment”—not policy discussions—about the potential risks of GHGs. The court also held that CAA § 202(a)(1) does not allow the EPA to consider, as part of the endangerment inquiry, the implications or impacts of regulations that might result from a positive endangerment finding.

  1. The Scientific Record

Petitioners also challenged the adequacy of the scientific record underlying the endangerment findings. Petitioners initially challenged the EPA’s reliance on publications issued by the Intergovernmental Panel on Climate Change (IPCC), the U.S. Global Climate Research Program, and the National Research Council.  The court summarily rejected this argument, noting the scientific literature was peer-reviewed and consisted of thousands of individual studies on GHGs and climate change. The court also rejected, as “little more than a semantic trick,” that EPA delegated its authority by relying on these studies. The EPA relied on the reports not as substitutes for its own judgment but as evidence upon which it relied to make its ultimate judgment. The court noted that EPA is not required to re-prove “the existence of the atom every time it approaches a scientific question.”

Finally, in their challenge to the adequacy of the scientific record, Petitioners argued EPA erred in reaching the Endangerment Finding due to scientific uncertainty surrounding climate change. The court responded by noting the “substantial” body of scientific evidence supporting the Endangerment Finding. The court held the existence of some uncertainty does not, without more, warrant invalidation of an endangerment finding. The statute itself is designed to be precautionary in nature and to protect the public health. Further, the Supreme Court itself ruled in Massachusetts v. EPA that the agency may make an endangerment finding despite lingering uncertainty. The court held that the EPA’s decision was supported by substantial evidence and that the agency had relied on the scientific record “in a rational manner.” The court noted that it was not its role to reweigh the evidence before it and reach its own conclusion.

  1. Lack of a quantitative threshold

Petitioners contended that the Endangerment Finding was arbitrary and capricious because the EPA did not define, measure or quantify either the atmospheric concentration at which GHGs endanger the public health or welfare, the rate or type of climate change anticipated to endanger the public welfare, or the risk or impacts of climate change. The court, again relying on the plain language of CAA § 202(a)(1), held that EPA is not required to establish a precise numerical value as part of its endangerment findings. Instead, section 202(a)(1) allows for a qualitative approach that allows the EPA to make case-by-case determinations based on the potential severity of harm in relation to the probability that the harm will occur.

  1. EPA’s definition of “air pollutant”

EPA defined the GHG “air pollution” and “air pollutant” subject to the Endangerment Finding as an aggregate of six GHGs, which the EPA called “well mixed greenhouse gases”: carbon dioxide, methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). Industry Petitioners argued EPA’s decision to include PFCs and SF6 was arbitrary and capricious because motor vehicles do not emit these pollutants. The court responded that no petitioner established standing to make this argument, as no petitioner could demonstrate an injury-in-fact resulting from EPA’s decision to include PFCs and SF6 in the Endangerment Finding.

  1. Failure to submit Endangerment Finding for review by Science Advisory Board

Petitioners claimed that the EPA’s failure to submit the Endangerment Finding to the Science Advisory Board (SAB) violates its mandate to “make available” to the SAB “any proposed criteria document, standard, limitation, or regulation under the Clean Air Act” at the time it provides the same “to any other Federal agency for formal review and comment.” The court noted that it wasn’t clear this obligation was even triggered because it wasn’t clear that the EPA provided the Endangerment Finding to any Federal agency for formal review and comment—it had only been submitted to the Office of Information and Regulatory Affairs pursuant to Executive Order 12,866 for informal review. The court found that even if the EPA violated its mandate by failing to submit the Endangerment Finding to the SAB, Petitioners did not show this error was prejudicial to the rulemaking.

  1. Denial of petitions seeking reconsideration of Endangerment Finding

In the final challenge, Petitioners argued the EPA erred by denying all ten petitions for reconsideration of the finding. Petitioners asserted that internal documents and emails obtained from the University of East Anglia’s Climate Research Unit undermined the scientific evidence upon which the EPA relied. When determining whether to commence reconsideration of a rule, EPA considers an objection to be of “central relevance to the outcome” of that rule “if it provides substantial support for the argument that the regulation should be revised.” Additionally, the party raising the objection must demonstrate that it was impracticable to raise the objection during the public comment period.

The court rejected Petitioners’ assertion, finding that they failed to provide substantial support for their arguments that the Endangerment Findings should have been revised. The assessment had relied on over 18,000 peer-reviewed studies, and two errors identified in IPCC reports were harmless because EPA did not actually rely on such errors to reach the positive Endangerment Finding. Isolated errors identified by Petitioners did not rise to the level of substantial evidence required to support their arguments to overturn the Endangerment Findings.

Challenges to the Tailpipe Rule

Petitioners did not directly challenge the vehicle emission standards set by the Tailpipe Rule, and instead argued the EPA acted arbitrarily and capriciously by failing to consider and justify the costs of its conclusion that the Rule triggers stationary-source regulation under the PSD Program and Title V. The court rejected this argument and held that once EPA made the Endangerment Finding, the language of section 202(a)(1) created a non-discretionary duty that the EPA adopt regulation applicable to vehicle GHG emissions. The court noted this interpretation was supported by the Supreme Court’s decision in Massachusetts v. EPA.

Petitioners also advanced a claim under the Administrative Procedures Act, alleging that EPA failed to show that the proposed standards “would meaningfully mitigate the alleged endangerment.” The court rejected this argument, indicating that petitioner misread earlier D.C. Circuit decisions on EPA air regulations. EPA was under no requirement to establish a particular level of mitigation that the regulation had to achieve. Instead, EPA was only required to show that the Tailpipe Rule would contribute to “meaningful mitigation of greenhouse gas emissions.”

Finally, the court rejected an argument made by Petitioners that EPA should have considered the cost of stationary source permitting that would follow adoption of the Tailoring Rule. The D.C. Circuit had previously held that section 202(a)(2) reference only compliance costs to the motor vehicle industry and does not mandate consideration of costs to other entities not directly subject to the proposed tailpipe emission standards.

Challenges to EPA’s interpretation of PSD Permitting, Timing and Tailoring Rules

Petitioners challenged EPA’s longstanding interpretation of the scope of the permitting requirements for construction and modification of major emitting facilities under the CAA. Since 1978, EPA has defined “major stationary source” as a source that emits major amounts of “any air pollutant regulated under the [CAA].” This interpretation held through EPA’s PSD regulations adopted in 1980 and 2002. “Any pollutant” was interpreted by the EPA to include both criteria pollutants for the National Ambient Air Quality Standards (NAAQS) and non-criteria pollutants. As a result, when EPA determined that GHGs would become a regulated pollutant, emissions of more than 100 or 250 tpy of GHGs would trigger a PSD permitting requirement. Petitioners challenged this interpretation and argued that EPA could and should have avoided extending the PSD permitting program to major GHG emitters. The court adopted a plain meaning of section 169(1), which requires PSD permits for stationary sources emitting major amounts of “any air pollutant.” Both the EPA and the Supreme Court in Massachusetts v. EPA clearly established that GHGs are air pollutants. As a result, the court rejected Petitioners’ arguments that EPA should not have extended the PSD permitting program to major GHG emitters. The court rejected the Petitioners’ alternative interpretations of the PSD permitting triggers, as none cast doubt on the unambiguous nature of the statute.

Petitioners also challenged the Tailoring and Timing Rules established by EPA to facilitate initial regulations of GHGs. The court determined Petitioners lacked standing to challenge these two Rules because none had suffered an injury-in-fact as a result of the rules. Instead, the court found the Timing and Tailoring Rules actually mitigated Petitioners’ purported injuries, as many would be subject to PSD and Title V permitting requirements at an earlier time absent the rules.