Attorneys General from 17 states and the District of Columbia, the Corporation Counsel for the City of New York, the City Solicitor of Baltimore, and 13 environmental advocacy groups have asked the U.S. Court of Appeals for the District of Columbia Circuit to order EPA to respond to last year's landmark ruling in Massachusetts v. EPA. That ruling, which the U.S. Supreme Court issued exactly one year ago, required EPA to make a decision on whether to regulate greenhouse gas (GHG) emissions from motor vehicles under the federal Clean Air Act. A year later, EPA has not issued a decision. This court filing, known as a Petition for Mandamus, requests an order requiring EPA to act within 60 days.

In Massachusetts v. EPA, the Supreme Court ruled that--contrary to the Agency's claim--EPA has authority to regulate GHG under the Clean Air Act. The Court also declared that the Agency could not refuse to exercise that authority based on the Agency's policy preferences. Instead, EPA would have to decide, based on scientific information, whether it believed that GHG emissions were posing dangers to public health or welfare.

According to the petition, after last year's ruling, EPA publicly made clear its belief that GHG were, in fact, endangering public health or welfare. Once EPA comes to that judgment, it must regulate greenhouse gases under the Clean Air Act. On multiple occasions, the Agency promised that it would respond to the Supreme Court's opinion by issuing an endangerment determination and draft motor vehicle emission standards by the end of last year.

When it recently decided whether California could set its own standards for GHG emissions from motor vehicles, EPA issued detailed findings about the widespread harms that GHG are causing. For example, the Administrator specifically found that "[s]evere heat waves are projected to intensify in magnitude and duration over portions of the U.S. where these events already occur, with likely increases in mortality and morbidity, especially among the elderly, young, and frail." EPA denied California's request only on the grounds that the many severe harms that California faced would also afflict other states across the country.

The petition further asserts that EPA has already prepared an endangerment determination. A Congressional investigation conducted by Congressman Henry Waxman confirmed that EPA, in fact, sent its draft endangerment determination and proposed regulations to the Office of Management & Budget in December 2007. According to the petition, an investigation conducted by the House Committee on Oversight and Government Reform established that consistent with its announced schedule, EPA implemented its internal process of drafting an affirmative endangerment determination during the fall of 2007.

EPA has now declined to issue that proposed endangerment determination, and it said that it would delay responding to the Supreme Court's opinion until after it conducts a lengthy public comment period later this year to examine policy issues raised by regulating GHG under the Clean Air Act.

Included in the Petition for Mandamus are: the states of Arizona, California, Connecticut, Delaware, Illinois, Iowa, Maine, Maryland, Massachusetts, Minnesota, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, Washington, and the District of Columbia; the City of New York; and the Mayor and City Council for Baltimore; Center for Biological Diversity; Center for Food Safety; Conservation Law Foundation; Environmental Advocates; Environmental Defense Fund; Friends of the Earth; Greenpeace; International Center for Technological Assessment; Natural Resources Defense Council; Sierra Club; and the U.S. Public Interest Research Group. All of these parties were either petitioners in Massachusetts v. EPA, or joined amicus briefs in support of the petitioners.