Maryland Bar Bulletin
Publications : Bar Bulletin : August 2008


On July 11, 2008, the U.S. Environmental Protection Agency (EPA) issued an Advanced Notice of Public Rulemaking (ANPR) to invite public comment on the benefits and potential ramifications of regulating greenhouse gas emissions from motor vehicles under the Clean Air Act (CAA). In a preface to the ANPR, however, EPA Administrator Stephen L. Johnson says that the CAA is “ill-suited for the task of regulating global greenhouse gases” and “would be relatively ineffective at reducing greenhouse gas concentrations given the potentially damaging effect on jobs and the U.S. economy.” The 589-page ANPR summarizes EPA’s analysis of the many complex challenges that would be faced in regulating greenhouse gases under the CAA. Because regulation of greenhouse gas emissions from motor vehicles under the CAA could also trigger the regulation of smaller sources such as apartment buildings, hospitals and large homes, EPA says that such regulation may have “a profound effect on virtually every sector of the economy and touch every household in the land.” Rather than trying to regulate greenhouse gas emissions under the “ill-suited” CAA, the ANPR suggests that Congress should enact comprehensive climate change legislation instead. Unless Congress acts, however, EPA will be forced to proceed with developing regulations under the CAA. EPA is accepting public comments on the ANPR for 120 days following publication in the Federal Register.

Massachusetts v. EPA

The ANPR represents EPA’s response to the U.S. Supreme Court’s decision in Massachusetts v. EPA, decided in April 2007. The genesis of Massachusetts v. EPA was a rulemaking petition filed in 1999 asking EPA to regulate under the CAA greenhouse gas emissions including carbon dioxide from new motor vehicles. EPA denied the petition, concluding that it lacked authority under the CAA to regulate greenhouse gases for purposes of global climate change and, even if it had the authority, it would be unwise to do so at this time. A group of states, local governments and environmental organizations challenged EPA’s denial of the rulemaking petition in the U.S. Court of Appeals for the District of Columbia Circuit. In a 2-1 decision, the court assumed for purposes of argument that EPA had authority to regulate greenhouse gases, but held that EPA had properly exercised its discretion not to do so.

The U.S. Supreme Court reversed and held that EPA had improperly denied the rulemaking petition. The Court concluded that carbon dioxide and other greenhouse gases met the definition of “pollutants” under the CAA because they are “physical [or] chemical substance[s] or matter which [are] emitted into . . . the ambient air.” The Court rejected EPA’s asserted reasons for failing to regulate greenhouse gases and held that EPA is required to determine whether greenhouse gases contribute to air pollution that may reasonably be anticipated to endanger public health or welfare. If EPA makes a finding that greenhouse gas emissions from new motor vehicles meet the endangerment test, EPA then will be required to begin rulemaking to regulate greenhouse gases emissions for new motor vehicles under the CAA.

EPA’s Advanced Notice of
Public Rulemaking

So far, EPA has been reluctant to make a finding that greenhouse gas emissions from new motor vehicles meet the endangerment test. Instead, EPA announced that it would issue an ANPR to seek comment on the consequences of regulating greenhouse gas emissions under the CAA. The ANPR does not propose any particular regulatory action, but summarizes existing CAA programs and evaluates how they might be used to regulate greenhouse gases. The ANPR discusses issues and approaches to consider in designing greenhouse gas control measures that may be useful in developing either legislation or regulations to reduce greenhouse gas emissions. The ANPR also includes almost 90 pages of concerns raised by other federal agencies during their review of an earlier draft.

According to the ANPR, regulating greenhouse gas emissions under the CAA would be extremely challenging. As Administrator Johnson describes it, the CAA is “an outdated law originally enacted to control regional pollutants that cause direct health effects” and, therefore, is “ill-suited” to regulate greenhouse gas emissions. The CAA was designed to improve and maintain air quality in the United States by controlling specific sources of air pollution within a particular State or local area. Emissions requirements under the CAA are generally premised on a health-based or public welfare-based air-quality standard. Greenhouse gases, on the other hand, are emitted all over the world by a variety of human and natural sources, mix freely in the atmosphere and remain in the atmosphere for long periods of time. It is unclear whether limiting greenhouse gas emissions from particular sources in the United States would effectively address global climate change, particularly if other countries do not also limit emissions.

Much of the ANPR is devoted to a detailed examination of the various provisions of the CAA, how they may be used to regulate greenhouse gas emissions and the implications of such regulation. For example, because similar endangerment language is found in numerous sections of the CAA, a finding of endangerment under one provision could significantly impact EPA’s decisions on endangerment under other provisions. Another issue is whether EPA should define greenhouse gases as “air pollutants”, either individually or collectively, which could impact EPA’s flexibility to define greenhouse gases as pollutants in other sections of the CAA.

Regulation of greenhouse gas emissions from motor vehicles could also lead to the regulation of numerous other sources. Since the Supreme Court’s decision, EPA has received several petitions to set emissions standards for other types of mobile sources, such as construction and farm equipment, ships and aircraft. Regulation under the CAA could also trigger the regulation of smaller stationary sources that also emit greenhouse gases, such as apartment buildings, hospitals, schools and large homes.


Given the complexities inherent in regulating greenhouse gases under the CAA, it will likely take the EPA a long time to develop and propose regulations. As the ANPR suggests, federal legislation may be a more appropriate way to address the nation’s greenhouse gas emissions. New legislation could be tailored to provide more flexibility to deal with issues unique to greenhouse gases than that which is available under the CAA. To date, however, Congress has been unable to enact comprehensive climate change legislation. Unless and until such legislation is enacted, EPA will be required to proceed with promulgating greenhouse gas regulations under the CAA.

Margaret Witherup Tindall is a member of the Environmental & Energy and Litigation Departments of Gordon, Feinblatt, Rothman, Hoffberger & Hollander, LLC. She concentrates her practice in environmental law and complex commercial litigation.

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Publications : Bar Bulletin: August 2008

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