Clean Air Act: EPA Has Completed Most of the Actions Required by the 1990 Amendments, but Many Were Completed Late

While air quality in the United States has steadily improved over the last few decades, more than a hundred million Americans continue to live in communities where pollution causes the air to be unhealthy at times, according to the Environmental Protection Agency (EPA). The Clean Air Act, first passed in 1963, was last reauthorized and amended in 1990, when new programs were created and changes were made to the ways in which air pollution is controlled. The 1990 amendments included hundreds of requirements for EPA, as well as other parties, to take steps that will ultimately reduce air pollution. The amendments also established deadlines for many of these requirements. Since the 1990 amendments, various actions have been proposed to either amend the Clean Air Act or implement its provisions in new ways. GAO was asked to report on the current status of EPA's implementation of requirements under Titles I, III, and IV of the 1990 amendments. These titles, which address national ambient air quality standards, hazardous air pollutants, and acid deposition control, respectively, are the most relevant to proposed legislation and recently finalized regulations addressing emissions of air pollutants by power plants.