ABSTRACT
Unlike the regulation of sulfur dioxide and other so-called criteria pollutants, control of hazardous air pollutants (HAPs) in the United States is a relatively recent phenomenon. Apart from early steps to control toxics such as vinyl chloride, which the U.S. Environmental Protection Agency (EPA) regulated in 1976, most regulation of HAPs has been based on new provisions added in the 1990 Clean Air Act Amendments.
