Ch. 5: Air Pollution Control


On June 29, 2015, the Supreme Court decided that EPA must first consider costs before deciding to regulate emissions of hazardous air pollutants from electric utilities.  In Michigan v. EPA the Court held by a 5-4 vote that § 112(n)(1)(4) of the Clean Air Act’s requirement that EPA determine that regulation of such emissions is “appropriate and necessary” requires consideration of costs.  An edited copy of the decision is contained in the 2015-16 Statutory and Case Supplement.  The extent to which costs can be considered under § 112 is covered in more detail in Chapter 3, pp. 303-326.  On remand, the D.C. Circuit decided on Dec. 15, 2015 not to vacate the mercury rule that was the subject of the successful challenge in the Supreme Court.  Because EPA already has extensively considered the cot of the mercury regulations, it should have little difficulty complying with the Michigan v. EPA decision.


On October 15, 2013 the U.S. Supreme Court announced that it would review one portion of the D.C. Circuit’s decision in Coalition for Responsible Regulation v. EPA.  The Court limited its review to a single question: “Whether EPA permissibly determined that its regulation of greenhouse gas emissions from new motor vehicles triggered permitting requirements under the Clean Air Act for stationary sources that emit greenhouse gases.”  This meant that the Court would not review EPA’s endangerment finding or tailpipe rule.  The focus in the Supreme Court instead was on whether EPA can use the prevention of significant deterioration (PSD) permit program to regulate new sources of greenhouse gas emissions.  For an excellent blog post describing what issues were and were not before the Supreme Court in this case, see the explanation from NRDC’s David Doniger at:  The case was argued on February 24 and decided on June 23. On June 23 the Court decided the case by a 5-4 vote. 

In an opinion by Justice Scalia the Court affirmed in part and reversed in part the D.C. Circuit’s decision. The Court held “that EPA exceeded its statutory authority when it interpreted the Clean Air Act to require PSD and Title V permitting for stationary sources based on their greenhouse-gas emissions.” The Court held that EPA “may not treat greenhouse gases as a pollutant for purposes of defining a ‘major emitting facility’ (or a ‘modification’ thereof) in the PSD context or a ‘major source’ in the Title V context.” However the Court concluded that EPA may “continue to treat greenhouse gases as a ‘pollutant subject to regulation under this chapter’ for purposes of requiring BACT for ‘anyway’ sources.”  Justices Ginsburg, Breyer, Sotomayor and Kagan dissented.  In a concurring opinion Justices Alito and Thomas stated that they continued to believe that greenhouse gases cannot be regulated under the Clean Air Act, the position they articulated in Massachusetts v. EPA.  An edited copy of the Court’s decision is available in the 2014-15 Statutory and Case Supplement and also here: Utility Air Decision.docx

On September 20, 2013, EPA proposed new source performance standards (NSPSs) for new fossil-fueled powerplants that are widely viewed as precluding the construction of new coal-fired powerplants unless they employ expensive carbon capture and storage technology.  In June 2014 EPA proposed regulations to limit greenhouse gas emissions from existing powerplants pursuant to §111(d) of the Clean Air Act, which allows the agency to require states to regulate a pollutant for which it has established a NSPS if it is not already regulated as a criteria air pollutant with a national ambient air quality standard (NAAQS) or as a hazardous air pollutant subject to a national emissions standard for hazardous air pollutants (NESHAP). A copy of EPA’s proposed rule is available at: EPA finalized this rule on August 3, 2015.  EPA’s fact sheet on the final rule is available online at:

Even before the Clean Power Plan rule was adopted, industry groups filed lawsuits challenging it. In Nebraska v. EPA, No. 4:14-CV-3006 (D. Neb. Oct. 6, 2014), a federal district court dismissed one of these lawsuits as premature.  On April 16, 2015, the U.S. Court of Appeals for the D.C. Circuit heard oral argument on two other lawsuits seeking to halt the rulemaking - West Virginia v. EPA (No. 14-1146) and In re Murray Energy Corporation (No. 14-1112, 14-1151).  Even though the D.C. Circuit panel contained the court’s three judges most skeptical of EPA regulations, on June 9, 2014 they unanimously dismissed the lawsuits based on the fundamental principle that until EPA finalizes the rule there is no agency action that is subject to judicial review under the Clean Air Act or the Administrative Procedure Act.

EPA finalized the Clean Power Plan, with the rule published in the Federal Register in October 2015, "Carbon Pollution Emission Guidelines for Existing Stationary Sources: Electric Utility Generating Units," 80 Fed. Reg. 64,662 (October 23, 2015). Coal companies and attorneys general from red states then sought judicial review of the rule.  Environmental groups and officials from blue states are supporting EPA. The task facing EPA’s challengers will be even greater because of changes EPA made between its proposed and final rules.  EPA adopted the Clean Power Plan only after considering 4.3 million comments, the most the agency has ever received in any rulemaking action during its 45-year history.  The final regulations include some significant changes from the agency’s initial proposal, indicating that EPA listened carefully to the comments it received from electric utilities, the states, the public, trade associations, environmental groups, and others concerned about the regulations. 

EPA increased the flexibility afforded states in designing plans to determine the most efficient way to reduce emissions.  It also delayed for two years the initial compliance date for power plants, while providing incentives for early action to invest in renewable energy sources.  EPA also eliminated the fourth of its proposed “building blocks” that had focused on utilities getting their customers to use energy more efficiently.  In his Utility Air Regulatory Group (UARG) opinion, Justice Scalia had appeared to question EPA’s authority to require demand-side reduction programs under the Clean Air Act. Thus, EPA should find itself on an even firmer legal footing as it steers the country toward a new era of clean energy.

The number one legal argument the challengers make rests on the fact that two different versions of an amendment to delete an obsolete cross reference in the section of the Clean Air Act under which EPA’s regulations are issued (§ 111(d)) were adopted by Congress when it amended the Act in 1990.  Such mistakes often happen when enormously complex legislation is adopted under extreme time pressure. Neither version was discussed in committee hearings, floor debates, or the House/Senate conference, but they both were included in the final bill approved by both houses of Congress. The version of the amendment originating in the Senate provides that §111(d) cannot be used to regulate pollutants that already are regulated as hazardous air pollutants under a different section of the act, which GHGs are not.  Opponents of the Clean Power Plan argue instead that the version originating in the House that appears to bar regulation of any source category (such as power plants) that emits hazardous pollutants regulated under a different section of the Act should prevail.  EPA argues that the conflicting versions of § 111(d) create a statutory ambiguity that entitles the agency to receive deference for its interpretation of the Act — that the Senate version controls.  EPA clearly has the better of the argument given traditional doctrines of judicial deference to agency expertise, coupled with the fact that it makes policy sense to avoid duplicative regulation of particular pollutants, but not to exempt significant sources of a different pollutant from regulation. 

Recently, however, Chief Justice Roberts has suggested in a decision again upholding the Affordable Care Act (King v. Burwell) that normal doctrines of judicial deference may not apply when a regulation has “deep economic and political significance.”  This surely will be cited by opponents of the Clean Power Plan in arguing against deference to EPA.  Given that the Court frequently splits 5-4 in environmental cases with Justice Kennedy casting the crucial deciding vote (as he did in Massachusetts v. EPA), his view concerning the legality of the Clean Power Plan is crucial to its survival.

Opponents of the new source performance standard for GHG emissions and the Clean Power Plan tried to use the Congressional Review Act (p. 173 of casebook) to veto the EPA regulations through a special fast-track procedure permitting an up-or-down vote in each house of Congress.  On Nov. 17, 2015, the U.S. Senate passed a joint resolution of disapproval of the NSPS by a vote of 52-46 with only three Democrats supporting the resolution and three Republicans voting against it. The NSPS disapproval resolution was adopted by the House by a vote of 235-188 on Dec. 1, 2015, even as the Paris climate negotiations were taking place.  Only four Democrats supported the resolution, while 10 Republicans voted against it.  A resolution disapproving the Clean Power Plan regulations for existing power plants passed the Senate on Nov. 17, 2015 by a vote of 52-46.   The resolution passed the House by a vote of 242-180 on Dec. 1, 2015.  As promised, President Obama vetoed both joint resolutions of disapproval on Dec. 18, 2015. As a result, the regulations remain in effect.

After the DC Circuit denied the petitioners request for a stay of the Clean Power Plan on January 21, 2016, the petitioners filed a stay request with the U.S. Supreme Court.  In an unprecedented action, the Supreme Court stayed the regulations by a vote of 5-4.  The regulation were “stayed pending disposition of the applicants’ petitions for review in the United States Court of Appeals for the District of Columbia Circuit and disposition of the applicants’ petition for a writ of certiorari, if such writ is sought.  If a writ of certiorari is sought and the Court denies the petition, this order shall terminate automatically.  If the Court grants the petition for a writ of certiorari, this order shall terminate when the Court enters its judgment.”  For a criticism of the stay by the lead author of the casebook, see “In Blocking EPA Clean Power Plan Is the Supreme Court Wading Deeper into Politics?” The Conversation, Feb. 12, 2016 (

The legal challenges to the Clean Power Plan were argued in the D.C. Circuit en banc on September 27, 2016. Ten of the court’s eleven judges (all but Supreme Court nominee Merrick Garland) heard the oral argument, which lasted for the entire day.  Based on the questioning, most observers believe that EPA has a good chance of having the Clean Power Plan upheld.  However, it is likely that the Trump administration will try to rescind the regulations.

On March 28, 2017, President Donald Trump issued Executive Order 13,783 on “Promoting Energy Independence and Economic Growth.”  A copy of the order is available online at:  The order requires agencies to conduct an immediate review of all actions that potentially burden the safe, efficient development of domestic energy resources. It directs that President Obama’s June 2013 Climate Action Plan be rescinded along with Executive Order 13,653 on Preparing the United States for the Impacts of Climate Change, the September 2016 Presidential Memorandum on Climate Change and National Security, and the Council on Environmental Quality’s Final Guidance for Federal Departments and Agencies on Consideration of Greenhouse Gas Emissions and the Effects of Climate Change in National Environmental Policy Act Reviews (81 Fed. Reg. 51866 (Aug. 5, 2016)).  EO 13,783 also directs the EPA Administrator to review EPA regulations implementing the Clean Power Plan and, if appropriate, to suspend, revise, or rescind them.


In Rocky Mountain Farmers Union v. Corey, 730 F.3d 1070 (9th Cir. 2013), a divided panel of the U.S. Court of Appeals for the Ninth Circuit rejected a constitutional attack on California’s ambitious effort to reduce carbon emissions in the state.  The court found that California’s Low Carbon Fuel Standard (LCFS), which requires a ten percent reduction in the carbon intensity of fuels used in the state, did not violate the dormant commerce clause.  Even though the LCFS used the location from which fuel was transported as one factor in calculating lifecycle carbon intensity of fuels, the court found that the legislation was not facially discriminatory against interstate commerce because the location where fuels originate is only one factor that is considered and it is considered properly with respect to location’s impact on each fuel’s carbon footprint.  The court found that the law had no protectionist purpose and that it disadvantaged California corn ethanol producers because they had to transport the corn they used into the state while Brazilian ethanol producers were advantaged because their products were efficiently shipped to California by sea even though they traveled greater distances.  The Ninth Circuit panel also rejected the notion that the LCFS tries to control extraterritorial conduct in a manner that violates the dormant commerce clause. “The Commerce Clause does not protect Plaintiffs’ ability to make others pay for the hidden harms of their products merely because those products are shipped across state lines.  The Fuel Standard has incidental effects on interstate commerce, but it does not control conduct wholly outside the state.”  The court held that §211(c)(4)(B) of the Clean Air Act, which waives for California the express preemption provisions of the Act, did not insulate the state from liability if it otherwise violated the dormant commerce clause. Having rejected the facial discrimination claim, the court remanded the case back to the lower court to assess whether the law unduly burdened interstate commerce under the Pike v. Bruce Church test.  The dissenting judge would have held that the law was facially discriminatory because it used location as one factor in calculating carbon intensity. 

The plaintiffs then sought rehearing en banc in the 9th Circuit, which denied en banc review over a strong dissent joined by five judges.  However, when the plaintiffs then sought review by the U.S. Supreme Court, the Court denied review in June 2014.


On July 23, 2013, a three-judge panel of the U.S. Court of Appeals for the D.C. Circuit unanimously upheld EPA’s revised primary national ambient air quality standard (NAAQS) for ozone.  In Mississippi v. EPA, 723 F.3d 246 (D.C. Cir. 2013), the court rejected industry claims that it should not have replaced the old 8-hour primary standard of 0.08 ppm with the lower standard of 0.075 ppm that it promulgated.  It also rejected arguments by environmental groups and state governments that EPA should have accepted the lower level of 0.070 ppm recommended by its Clean Air Scientific Advisory Committee (CASAC), instead of the 0.075 ppm standard it promulgated.  The court explained that:

    “Although CASAC stated that ‘overwhelming scientific evidence’ supported its recommendation that the             standard be set no higher than 0.070 ppm, it never explained whether this proposal was based on its scientific judgment that adverse health effects would occur at that level or instead based on its more qualitative judgment that the range it proposed would be appropriately protective of human health with an adequate margin of safety. Indeed, although CASAC concluded that ‘there is no longer significant scientific uncertainty regarding [its] conclusion that the current 8–hr primary NAAQS must be lowered,’ given the ‘large body of data clearly demonstrat[ing] adverse human health effects at the current level,’ CASAC recognized that ‘[s]cientific uncertainty does exist with regard to the lower level of ozone exposure that would be fully-protective of human health.’ Oct. 2006 CASAC Letter, at 5.

    “To be sure, EPA's statutory obligation to respond to CASAC does not evaporate whenever CASAC exercises judgment amidst scientific uncertainty. Quite to the contrary, had CASAC acknowledged uncertainty in the scientific evidence but explained that, based on its expert scientific judgment, it nonetheless believed adverse health effects were likely to occur at the 0.070 ppm level, then section 307(d)(6) would have required EPA to explain why it disagreed with this scientific conclusion. Put differently, to the extent that CASAC has exercised scientific judgment, EPA must respond in kind. But because CASAC never made clear the precise basis for its recommendation, all we know for certain is this: both CASAC and EPA believed the existence of adverse health effects to be certain at the 0.08 ppm level and reached differing conclusions about what level below 0.08 ppm was requisite to protect the public health with an adequate margin of safety.

    “The task of determining what standard is ‘requisite’ to protect the qualitative value of public health or what margin of safety is ‘adequate’ to protect sensitive subpopulations necessarily requires the exercise of policy judgment. Here, EPA's policy judgment was informed by its view of the limitations of the scientific evidence—namely, that at lower levels of ozone exposure, the clinical and epidemiological studies provide less conclusive evidence of the existence of adverse health effects. Striking a balance between ‘the increasing uncertainty associated with [its] understanding of the likelihood of such effects at lower O3 exposure levels’ and ‘concern about the potential for health effects and their severity,’ EPA set the standard at 0.075 ppm, a level the agency believed to be ‘appreciably below’ the 0.08 ppm level at which both EPA and CASAC expressed certainty about the existence of adverse health effects. Absent a definitive scientific conclusion from CASAC that adverse health effects would occur at the 0.070 ppm level, we must assume that it too took these same considerations into account and simply exercised its judgment to recommend a standard set at a lower level. Although both CASAC and EPA must exercise public health policy judgment when confronted with scientific evidence that does not direct it to a specific outcome, it is to EPA's judgment that we must defer.

    “In our view, this conclusion is perfectly consistent with the role Congress intended CASAC to play in the NAAQS-setting process. In order to ensure that EPA's NAAQS decisions rest on sound scientific judgment, Congress required EPA not only to describe CASAC's recommendations in any rulemaking but also, if it departs from such recommendations, to explain its reasons for doing so. But in order for EPA to explain adequately its reasons for disagreeing with CASAC, CASAC itself must be precise about the basis for its recommendations. Because in this case CASAC failed to specify whether the 0.070 ppm level it recommended as a maximum rested on a scientific conclusion about the existence of adverse health effects at that level, EPA's invocation of scientific uncertainty and more general public health policy considerations satisfies its obligations under the statute.”

    The court went on to remand for reconsideration EPA’s secondary standard for ozone, which the agency had set at the same level as the primary standard.  The court concluded that the agency had failed to explain why the standard was requisite to protect public welfare, as required by the statute.

    A copy of the court’s opinion is available online at:$file/08-1200-1447980.pdf


As noted on page on page 614, it was not until 1999 that EPA began enforcing the new source review (NSR) requirements for several coal-fired powerplants that had been modified without obtaining NSR permits requiring the use of best available control technology.  In a series of recent decisions, courts have ruled that new owners of such powerplants are not liable for the violations of their predecessors because the five-year statute of limitations has expired and the failure to obtain a permit is not a continuing violation of the Act.  On July 8, 2013, the U.S. Court of Appeals for the Seventh Circuit so ruled in U.S. v. Midwest Generation LLC, 720 F.3d 644 (7th Cir. 2013). The court stated that: “Today’s emissions cannot be called unlawful just because of acts that occurred more than five years before the suit began.” The court concluded that “enduring consequences of acts that precede the statute of limitations are not independently wrongful.”  The court noted that both the Eighth and Eleventh Circuits had reached similar conclusions in Sierra Club v. Otter Tail Power Co., 615 F.3d 1008 (8th Cir. 2010), and National Parks and Conservation Ass’n, Inc. v. Tennessee Valley Authority, 502 F.3d 1316 (11th Cir. 2007).  On August 21, 2013, the Third Circuit reached the same conclusion in U.S. v. EME Homer City Generation, L.P., 2013 WL 4437219 (3d Cir. 2013). For an argument to the contrary see Paul Wierenga, Effective Clean Air Act Enforcement in the Face of Statute of Limitations and Successor Liability Barriers, 43 Envt’l L. Rep. 10607 (2013).


An excerpt from the D.C. Circuit’s EME Homer City decision striking down EPA’s Clean Air Interstate Rule (CAIR) has been included in the 7th edition of the casebook on page 651.  On June 24, 2013 the U.S. Supreme Court agreed to review the D.C. Circuit’s decision at the behest of both the U.S. Environmental Protection Agency and the American Lung Association.  The Court heard oral argument in the case on December 10, 2013. On April 29, 2014, the Court reversed the D.C. Circuit.  In an opinion by Justice Ginsburg, joined by Chief Justice Roberts and Justices Kennedy, Breyer, Sotomayor and Kagan, the Court determined that EPA had acted properly under the Clean Air Act when it promulgated the Clean Air Interstate Rule. Justices Scalia and Thomas dissented.  Justice Alito recused himself from the case.  An edited copy of the decision is available in the 2014-15 Statutory and Case Supplement and also at: EME Homer SCS.docx