Legal Authorities Defining Hazardous Substances

Superfund's definition of a hazardous substance includes the following:

• Any element, compound, mixture, solution, or substance designated as hazardous under section 102 of CERCLA.
• Any hazardous substance designated under section 311(b)(2)(a) of the Clean Water Act, or any toxic pollutant listed under section 307(a) of the Clean Water Act. There are over 400 substances designated as either hazardous or toxic under the CWA.
• Any hazardous waste having the characteristics identified or listed under section 3001 of the Resource Conservation and Recovery Act.

Hazardous waste is defined under RCRA as a solid waste (or combination of solid wastes) which, because of its quantity, concentration, or physical, chemical, or infectious characteristics, may: (1) cause or contribute to an increase in mortality or an increase in serious irreversible, or incapacitating illness; or (2) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, disposed of, or otherwise managed. In addition, under RCRA, EPA establishes four characteristics that will determine whether a substance is considered hazardous, including ignitability, corrosiveness, reactivity, and toxicity. Any solid waste that exhibits one or more of these characteristics is classified as a hazardous waste under RCRA and, in turn, as a hazardous substance under Superfund.

• Any hazardous air pollutant listed under section 112 of the Clean Air Act, as amended. There are over 200 substances listed as hazardous air pollutants under the CAA.
• Any imminently hazardous chemical substance or mixture which the EPA Administrator has "taken action under" section 7 of the Toxic Substances Control Act.

In all, more than 800 substances have been specifically identified as CERCLA hazardous substances under these laws.