Delays in EPA's Regulation of Hazardous Air Pollutants

In response to a congressional request, GAO provided information on: (1) how the Environmental Protection Agency (EPA) developed a list of 37 substances which are subject to review as hazardous air pollutants; (2) the procedures and practices followed by EPA in preparing health assessment documents; (3) Science Advisory Board (SAB) involvement in the hazardous air pollutant program; and (4) EPA progress in establishing standards.