The limits were aimed at improving the health of children and the elderly. The justices also rejected arguments by the American Trucking Associations and other industries that the EPA should have weighed the costs of compliance when setting rules under the Clean Air Act. The case raised questions of federal power dating from the New Deal era as well as practical issues of air quality. It drew broad interest from manufacturers and environmentalists, factory-rich Midwestern states and downwind Eastern states. Environmentalists say the ruling will help the EPA reduce illness and deaths caused by pollution.
Businesses note that other legal challenges remain.
The ruling also rejected EPA's precise schedule for ozone standards. Former EPA chief Carol Browner, however, said the rules are legal. Gannett Co. Inc. Shop.