Massachusetts v. Environmental Protection Agency


Where the EPA Administrator is required by the Clean Air Act to set auto emission standards for pollutants that may endanger public health, may the Administrator decline to do so for policy reasons not specifically found in the Clean Air Act and does the EPA Administrator actually have authority to regulate certain air pollutants associated with climate change under the Clean Air Act?

Oral argument: 
November 29, 2006

In October 1999, several environmental groups petitioned the U.S. Environmental Protection Agency (the “EPA”) to use its power to regulate carbon dioxide and other greenhouse gases from new motor vehicles. According to these groups, greenhouse gases should be classified as “air pollutants,” which can be regulated under the Clean Air Act if they “can be reasonably anticipated to endanger public health or welfare.” Among the possible “dangers” to welfare, the Clean Air Act lists effects on “weather” and “climate.” However, almost four years later, the EPA officially denied the petition, saying that the Clean Air Act did not give the EPA the authority to regulate greenhouse gas emissions and, even if it did, the EPA would deny the exercise of such authority. According to the EPA, the causal link between greenhouse gases and global warming has not been proven conclusively. Clearly, the Court’s decision in this case will have a significant effect on federal, state, and local efforts to curb greenhouse gas emissions. Furthermore, the Court’s decision could determine the amount of deference that a federal agency should receive in its determinations and could lend credibility to particular side of the scientific argument concerning the tie of greenhouse gases to global warming.

Questions as Framed for the Court by the Parties 

1. Whether the EPA Administrator may decline to issue emission standards for motor vehicles based on policy considerations not enumerated in section 202(a)(1) [of the Clean Air Act].

2. Whether the EPA Administrator has authority to regulate carbon dioxide and other air pollutants associated with climate change under section 202(a)(1).


In October of 1999, the International Center for Technology Assessment (the “CTA”) petitioned the EPA to regulate carbon dioxide and three other greenhouse gasses released by motor vehicles as per § 202(a) of the Clean Air Act, 42 U.S.C.§ 7521(a)(1). Upon consideration of the petition, the EPA concluded it did not have authority under the Clean Air Act (the “Act”) to regulate greenhouse gas emissions from motor vehicles. Mass. v. EPA, 415 F3d 50, 53 (C.A.D.C. 2005). The EPA added that even if the CAA granted the EPA authority to regulate greenhouse gas emissions, the EPA could use its discretion to not exercise its authority at the present time. Id.

In response to the EPA’s decision twelve states (California, Connecticut, Illinois, Maine, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont and Washington); three cities (New York City, Baltimore, and Washington D.C.); and several agencies including the Environmental Defense Fund, Greenpeace and the Sierra Club, sued the EPA before a three-judge panel of the U.S. Court of Appeals for the D.C. Circuit. The Court of Appeals upheld the EPA’s decision to deny the CTA’s petition after finding that the “EPA administrator properly exercised his discretion under § 202(a)(1) in denying the petition for rulemaking” to curb emissions of greenhouse gasses. Mass v. EPA, 415 F3d 50, 58. On October 23, 2003, the Commonwealth of Massachusetts and 29 other parties petitioned for certiorari and requested that the EPA ruling and the Court of Appeals decision be reviewed and reversed. The Supreme Court granted certiorari on June 26, 2006.

The issues in this case pivot on whether the greenhouse gasses at issue are air pollutants and whether they have effects on the health and welfare of the public. The United States Code defines several key terms used in the Act. An “air pollutant” is “any air pollution agent or a combination of such agents, including any physical, chemical, biological, [or] radioactive substance or matter which is emitted into or otherwise enters the ambient air including any precursors to the formation of an air pollutant.” Id. at 3. “Effects on Welfare” is defined as including effects on “soil, water, crops, vegetation, manmade materials, animals, wildlife, weather, visibility, climate, damage to property, effects on the economic value of property, and personal comfort and well-being.” Id.

Much of the disagreement between the EPA and the Petitioners lies in their different interpretations of not only the Act but also of scientific research relating to the effects of greenhouse emissions. The EPA takes several positions that lead it to conclude that it is under no obligation to regulate greenhouse gasses, arguing that the Act does not authorize the EPA to regulate the greenhouse gasses at issue and that there is insufficient evidence linking greenhouses gasses to effects on public welfare for the EPA to take regulatory action. Id. at 4. Petitioners claim that the EPA is misinterpreting the law and scientific findings. Petitioners argue that several research findings link the noxious gasses to global warming and therefore the EPA has an authority to regulate and is required to regulate greenhouse gas emissions from motor vehicles under the Act.

The Supreme Court of the United State will hear oral arguments for this case, which many are calling the most important environmental case in U.S. history, during the month of November 2006.


Reviewing the EPA’s Denial to Regulate

Before the Supreme Court reaches the merits of this case, it will have to resolve two jurisdictional issues dealing with the Court’s authority to hear this case. The first jurisdictional issue is whether the Court has authority under the Clean Air Act (the “Act”) to review a denial of a petition for rulemaking. Mass. v. EPA, 415 F.3d 50, 54 (C.A.D.C. 2005). Serving as a possible basis for jurisdiction, Section 307(b)(1) of the Act gives the US Court of Appeals of the District of Columbia jurisdiction over “nationally applicable regulations promulgated, or final actions taken, by the administrator.” Id.

In this case, where the EPA decided against promulgating “nationally applicable regulations” after being asked to do so, the lower Court of Appeals has jurisdiction only if the EPA engaged in a “final action” under the meaning of the statute. Id. Addressing this issue, the Court of Appeals determined that the denial of the states’ rulemaking petition was a “final action” by the EPA, granting the Court of Appeals of the District of Columbia the proper jurisdiction to hear the case. Id.

Determining the Petitioners’ Standing to Sue

The second jurisdictional issue the Supreme Court must address is whether Petitioners in this case have standing to bring a suit against the Environmental Protection Agency. Id. This argument is not based on the language of the Act. Rather, Respondent bases this argument on Article III of the U.S. Constitution. Id. The EPA argues that the petitioners have not “adequately demonstrated” two fundamental elements of standing: that their alleged injuries were caused by the EPA’s decision not to regulate emissions of greenhouse gases from mobile sources; and that their injuries can be redressed by a decision in their favor by the Court. Brief for Respondent at 11.

The EPA argues that Petitioners do not have standing to bring this case because they have failed to allege and show any particularized harm for each individual state. Id at 14. Instead, says the EPA, Petitioners have shown only that emissions of certain gases that the EPA had failed to regulate may cause an increase in the temperature of the earth, that this is a harmful phenomenon to humanity as a whole, and that Petitioners represent segments of humanity at large. Mass. v. EPA, 415 F.3d at 60. This argument, argues the EPA, is much too general and speculative to qualify as the kind of particularized harm necessary to make out an Article III controversy in federal courts. Brief for Respondent at 15.

Anticipating this argument, Petitioners filed two volumes of declarations with the court, from scientists, engineers, state officials, homeowners, users of the nation’s recreational resources, and other individuals. Mass. v. EPA, 415 F.3d at 54. The declarations as a whole predict drastic consequences from global warming caused by greenhouse gases, including loss of or damage to state and private property and increased health care costs. Id.

To specifically address the argument concerning standing, Petitioners argue, based on a couple of their declarations, that reductions in carbon dioxide and other greenhouse gases from vehicles in the United States would have a meaningful impact, delaying and moderating some of the adverse impacts of global warming. Id. One of the declarations bases its arguments on climate models and quantitative scenarios generated by the Intergovernmental Panel on Climate Change, established in 1988 by the United Nations and the World Meteorological Organization. Id. at 54-55.

To establish standing, Petitioners have to support each element of standing by affidavit or other evidence. Id. at 55. The lower court determined that Petitioners’ declarations clearly supported the elements of standing. Id. However, the court expressed doubt regarding whether these declarations actually proved Petitioners’ arguments. Id. In fact, the lower court pushed the question of standing aside, moving to the merits of the case and deciding on the EPA’s substantive reasons for deciding not to regulate greenhouse gases emitted from vehicles. Id. at 56.

According to the lower court, this decision to push aside standing is endorsed by Steel Co. v. Citizens for a Better Environment, 523 U.S. 83, 97 (1998), where the Court explained that “the merits inquiry and the statutory standing inquiry often overlap” in cases dealing with statutory standing and “are sometimes identical, so that it would be exceedingly artificial to draw a distinction between the two.” Id.

Authority of the EPA Administrator to Regulate

Both sides acknowledge that the EPA Administrator does have authority to regulate certain types of emissions. Under § 202(a)(1), the Administrator has the authority to establish national ambient air quality standards that “in the Administrator’s judgment, cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare” and whose presence in the air is from “numerous or diverse mobile or stationary sources.” The authority to impose regulations under the Act extends to the regulation of the emission of any air pollutant from any class or classes of new motor vehicles or new motor vehicle engines.

Argument Against the EPA’s Denial to Regulate

Regarding the merits of the case, Petitioners argue that their petitions to the EPA, which sought to have the EPA regulate the emissions of carbon dioxide and other greenhouse gasses from motor vehicles under § 202(a)(1) of the Act, were impermissibly denied. Brief for Petitioner at 8. According to Petitioners, the Act provides the clear statutory language necessary to permit the EPA Administrator to regulate these gasses. Id.

Under the Act, “effects on welfare” includes effects on “weather” and “climate,” among many other targets. Thus, say Petitioners, a substance emitted into the air that endangers climate is, under the express terms of the Act, subject to regulation under § 202 of the Act. Id. at 20. The fact that the EPA decided to decline to use its authority under the Act was influenced by “considerations” not found in the Act – an impermissible basis for such a decision, say Petitioners. Id. at 35.

Therefore, argue Petitioners, the EPA’s arguments regarding the “uncertainties” in the scientific community, the inefficiency of a “piecemeal approach” that only regulates vehicles, and the possibility of foreign policy concerns were insufficient to justify denial of the states’ petition seeking regulation. Mass. v. EPA, 415 F.3d at 58. The relevant provisions of the Act – dealing with “endangerment” – say Petitioners, do not contain a single word about technological judgments, international treaty negotiations, private-public partnerships, or any other of the myriad factors the EPA cited in deciding not to regulate here. Brief for Petitioner at 39.

Furthermore, argue Petitioners, the EPA is ignoring clear and growing evidence of the real harm being done by global warming. Petitioners explain that the presence of these gasses in our atmosphere are having a seriously detrimental effect on our natural environment and that their regulation would help alleviate some of the concerns with a worsening natural environment. Mass. v. EPA, 415 F.3d at 60. According to Petitioners, the current studies and models are sufficient to meet the requirement of a showing of “endangerment” of the “public welfare” in order to impose emission regulations. Brief for Petitioner.

Argument Favoring the EPA’s Denial to Regulate

In response to Petitioners, the EPA argues that it denied the petition to regulate these greenhouse gasses because it takes the position that the Act does not give authority to the EPA to regulate for the purpose of alleviating the problem of global climate change. Brief for Respondent at 20. Under the EPA’s reasoning, carbon dioxide and the other greenhouse gasses cannot be considered “air pollutants” under the Act and thus are not subject to its regulatory provisions. Id.

The EPA has explained that it is wary of using broad statutory language to impose regulations in areas that raise significant economic and political issues when Congress has already addressed those same areas in other statutes. The EPA notes that the few provisions that specifically mention “carbon dioxide” or “global warming” are non-regulatory in nature.

Also, the EPA argues that Congress had enacted non-Clean Air Act legislation in recent years that was specifically directed to the problem of climate change, and had rejected numerous attempts to give the EPA the proper authority to regulate greenhouse gas emissions to address climate change. Mass. v. EPA, 415 F.3d at 70. One of the main features of this problem is its international scope. Thus, the EPA also explains that efforts to regulate the greenhouse gas emissions from motor vehicles could interfere with the foreign policy considerations of the U.S., including any ongoing negotiations with other nations concerning the issue. Id. at 58.

Additionally, even if the EPA had the requisite authority under the Clean Air Act to address the issue, the agency has stated that it would deny the rulemaking petition, emphasizing that the effect of greenhouse gasses on the earth’s climate is unclear and that models used to predict climate changes might not be accurate. Id. at 57. The EPA has identified numerous areas of scientific uncertainty involving the mechanisms of climate change, its potential effect on human health and the environment, and the means by which such issues can most effectively be addressed. Id.

According to the EPA, it believes it inappropriate to regulate greenhouse gas emissions from vehicles until more is understood about the causes, extent, and significance of climate change, and the potential options for addressing the problem. Id. at 58. Furthermore, the EPA has identified a variety of ongoing efforts that are underway to further investigate the areas of scientific and technical uncertainty, arguing that establishing greenhouse gas emission standard for U.S. motor vehicles at this time would be premature and would require the EPA to proceed without the benefit of studies being developed to reduce the uncertainties in this field. Id.


The Supreme Court will decide during November of 2006 whether the statutory language of the Clean Air Act requires the EPA to regulate greenhouse gas emissions and if it does, whether the EPA has discretion to decline to regulate them. Many are calling this case the most important environmental case to reach the U.S. Supreme Court. The decision will affect federal, state, and local efforts to control greenhouse gas emissions in the fight against global warming.

If the Supreme Court decides that the Act does in fact grant the EPA the authority to regulate carbon dioxide, it may order the EPA to make appropriate regulations to curb greenhouse gas emissions. The court may also resend the case to the EPA for consideration in conformity with the court’s decision. A decision in favor of Petitioner may also require the Bush Administration to abandon its voluntary emission control policy and invest in creating regulations to curb greenhouse gas emissions and implimenting enforcement mechanisms to ensure compliance.

Such a decision would require industries such as car makers and fuel companies to spend a considerable amount of resources on scientific and technical research to create new car systems and fuel usages that would cut carbon dioxide emissions as per the new regulations. Because it is difficult to gage the time frame within which these scientific and technical changes can take place, it is not possible to know exactly when or how the industries that would be affected by new EPA regulations would be able to comply with them. The EPA argues that this uncertainty in application is precisely one of the reasons why the court should not rule in favor of Petitioner, allowing the agency to use its discretion to decline regulation of greenhouse gases at the present time.

The EPA argues further that there is a lack of concrete scientific evidence linking greenhouse gases to the environmental effects claimed by Petitioners. The EPA claims its position is supported by the National Research Council’s finding that “a causal linkage between greenhouse gas emissions and global warming cannot be unequivocally established” and thus it is under no obligation to regulate carbon dioxide under the Act. Mass v. E.P.A., 415 F3d at 57. The EPA posits that if the Act actually requires the agency to regulate greenhouse gases, it needs time to obtain the scientific, political, and policy knowledge that will enable it to create a practical method of curbing greenhouse gas emissions.

In its support of the EPA position, the U.S. Court of Appeals for the D.C. Circuit concluded that the EPA Administrator is not required to base his judgment solely on scientific evidence, but may also consider policy issues. Id at 58. One of the main policy considerations made by the EPA administrator was concern over taking a piecemeal approach to regulation which may later result ineffective. The EPA administrator also explained that there are alternative methods to deal with the matter, such as reducing gasoline consumption and improving tire performance, which can be implimented until conclusive evidence of the effects of greenhouse gas emissions is collected. The Court of Appeals concluded that based on the scientific uncertainty of the relationships between greenhouses gases and global warming, as well as policy considerations weighed by the EPA Administrator, the EPA acted properly by refusing to regulate greenhouse gases.

If the Supreme Court upholds the lower court decision, it will be a big blow to environmental group and state efforts to protect the environment through the immediate implementation of federal regulations. If the projections made by scientists in support of federal regulation of greenhouse gasses are correct, a court decision in favor of the EPA could lead to a devastating aggravation of greenhouse gas effects on the environment, such as dramatic climate changes. The weight of controlling greenhouse gas emissions will fall on local and state governments who are not only concerned about the environment, but also their ability to curb greenhouse gas emissions with their limited budgets, manpower and resources.

Petitoners’ decision to bring this case before the court is part of a larger effort to compel the Bush administration to take affirmative steps towards dealing with growing concerns over global warming by state governments, scientists, and environmental groups. The Bush Administration has opted for a more passive approach to curbing greenhouse via a voluntary greenhouse gas emission reduction system. Many scientists believe that the Bush Administration’s approach is not enough. Some scientific predictions show that failure to curb greenhouse gas emissions immediately will negatively impact the earth’s environement at an alarming rate.

To lend support to Petitioners’ arguments, several scientists submitted briefs detailing their observations of current environmental changes, such as increases in temperature, receding glaciers, and increasing acidity of the earth’s oceans. In sum, those scientists that support Petitioners’ position believe that time is of the essence and that the best way to push the Administration to deal with the problem with the requisite urgency is a Supreme Court decision requiring the EPA to regulate greenhouse gas emissions under the Clean Air Act. See Brief of Amici Curiae Climate Scientists at 7. However, not all scientists within the scientific community agree about the best way to interpret the scientific findings that currently exist regarding greenhouse gases.

Petitioners also argue that the EPA’s assertion that it lacks the authority to regulate greenhouse gas emissions under the Act is unfounded. Petitioners base their argument on several conclusions. First, the language of the Clean Air Act is very broad and interpreted to include regulation of greenhouse gases. Second, the only requirement for regulatory action is that there be a negative effect on the environment. Petitioners claim that the scientific evidence gathered by the EPA and several environmental groups all contain evidence linking the increase in greenhouse gas emissions to climate change and other negative environmental effects. Therefore, say Petitioners, the EPA is shunning its responsibility to protect the environment as required by the plain language of the Act, adding that the policy reasons offered by the EPA for denial of the petition are irrelevant. Mass. v. E.P.A., 415 F3d at 53.

The EPA has also been accused by several of the petitioner groups of misinterpreting scientific research results and politicizing the global warming issue, instead of making sound policy decisions that take into consideration scientific evidence. Richard Blumenthal, the Connecticut Attorney General, states that “the EPA is ignoring clear and growing evidence of real harm done by global warming . . . . The administration’s own studies show how greenhouse gas pollution causes disease, extreme weather, destruction of shoreline, and loss of critical wetlands and estuaries.” States, Cities, Environmental Groups Sue on Global Warming, Challenges E.P.A. Refusal to Reduce Greenhouse Gas Emissions, October 23, 2003.

While Petitioners urge that time is of the essence and action is needed now on the part of the federal government, the EPA argues that time is needed in order to figure out and better understand the problem in order to create viable, practical and effective solutions. Greenhouse gas emissions are an international problem and the EPA considers it is best to continue working with other countries in trying to learn more about the relationship between greenhouse gas emissions and the environmental changes noted by scientists in order to avoid the complications that would result from rushed, piecemeal solutions.

Although the EPA’s position is supported by the lower court, Petitioners have put forward arguments that raise grave concerns about the environmental effects that could flow from a Supreme Court decision interpreting the Act in favor of the EPA. Whether the Supreme Court agrees with Petioners or the EPA will heavily depend on the court’s determination of the congressional intent behind the Clean Air Act.


The Court’s decision in this case will have a significant impact on the future course of environmental regulation in the U.S. by determining the deference to be given to the EPA’s decision and deciding the proper reading to give the Clean Air Act. Clearly, the Court’s decision in this case will have a significant effect on federal, state, and local efforts to curb greenhouse gas emissions. A decision for Petitioners will negate the EPA’s arguments concerning the limited scope of the Clean Air Act and will force the EPA to regulate the emission of greenhouse gasses. However, a decision for Respondent will give credence to the high degree of deference for federal agencies advocated by the EPA and will allow the EPA’s denial to regulate to stand. Furthermore, although the Court is likely to base its decision on legal arguments concerning the statutory interpretation of the Act, the Court’s decision could implicitly lend credibility to a particular side of the scientific argument concerning the tie of greenhouse gasses to global warming.

Written by:

Heidy Abreu

Miguel Loza


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