Hazardous Air Pollutant in the United States

Hazardous Air Pollutant in Environmental Law

A chemical, compound, or particulate that Congress has placed on a list of pollutants that can cause health problems when discharged to the air. In 1970, the Environmental Protection Agency (EPA) was given the responsibility of listing hazardous air pollutants. However, only eight had been listed by the time the Clean Air Act Amendments of 1990 were passed, so Congress legislated its own list, including 189 substances.

History

The 1970 Clean Air Act mandated control of hazardous air pollutants. The EPA’s job was difficult, however. Before it could list a substance as a hazardous pollutant, it had to determine that it would cause health problems, what the standard should be to minimally protect the public, and then add an “ample measure of safety.”

Health based standards, such as those built into the 1970 Act, precipitated another problem. If health was to be the only consideration, how could cost or technological feasibility be factored into the equation? Public interest groups took the position that it could not be. The standard for a hazardous air pollutant, according to those groups, had to be zero.

The EPA had trouble determining which pollutants should be listed. At first, many people believed that the only significant exposures to hazardous air pollutants were in the workplace and the Occupational Safety and Health Administration was responsible for workplace safety. Another law changed that perception.

In 1986, when the Superfund law was amended, the Emergency Planning and Community RightToKnow Act became part of it. That law required public disclosure of releases, as well as planning for them. The Toxic Release Inventory was established; in it, information became available to the public and lawmakers for the first time.

The first Toxic Release Inventory of all reported releases of hazardous air pollutants reported under the Emergency Planning and Community RightToKnow Act was prepared in 1989. In 1990, Congress knew much more about the existing levels of exposure to various air pollutants. The listing problem was taken from the EPA, at least initially, and Congress created its own list. However, the EPA administrator can add or delete substances from it after making specified findings.

Technology Based Standards

A source considered major for hazardous air pollutants is much smaller than a major source for other types of air pollutants. If a source emits 10 tons per year of any one hazardous air pollutant or 25 tons per year of any combination of hazardous air pollutants, it is considered major. That means it is subject to more regulation than other sources.

Since the concept of basing control levels on health concerns had caused so much trouble, the 1990 Amendments moved to a technologybased standard like those used in other statutes. The level of control necessary for hazardous air pollutants became the technology required to get the maximum reduction in emissions or maximum achievable control technology (MACT). To determine what that means numerically, the EPA looks at the available technology and determines what the best technologies are. Then it sets standards based on what those controls can achieve.

According to the 1990 amendments, the EPA is to look first at technology. Later, consideration of health is to be factored in. See National Emission Standards for Hazardous Air Pollutants.
Based on “Environment and the Law. A Dictionary”.