On April 18, several groups appealed to the Supreme Court an appellate court June 2012 decision that upheld the Environmental Protection Agency’s (EPA’s) authority to generate greenhouse gas regulations for stationary sources. They asserted the EPA can only regulate carbon monoxide, lead, nitrogen oxides, ozone, particulate matter, and sulfur dioxide under the prevention of significant deterioration permitting program; they argued that the EPA could not regulate greenhouse gases. The petitioners included the American Chemistry Council, the American Fuel and Petrochemical Manufacturers, the American Petroleum Institute, the Coalition for Responsible Regulations, Alpha Natural Resources, Great Northern Project Development, the National Association of Home Builders, and the National Cattlemen’s Beef Association.