Carcinogens are substances that may cause or aggravate cancer. Many of the substances regulated by the EPA fall into this category. The Agency conducts and publishes risk assessment studies on individual carcinogens such as benzene, asbestos and butatdiene. On a larger scale, the EPA analyzes the long term carcinogenic effects of hazardous substances produces in industrial processes and left behind in hazardous waste sites. The EPA also researches the ways in which carcinogens are transported in the environment. Determining safe levels of exposure and promoting the use of alternates to carcinogens are part of the Agency's role in protecting human health and the environment.

Recommended EPA Web pages

• Guidelines for Carcinogen Risk Assessment (2005)
  This page provides links to information about cancer risk assessment guidelines.
• Commonly Encountered Radionuclides
  This page provides links to fact sheets about radionuclides.
• Fact Sheet: EPA's Guidelines for Carcinogen Risk Assessment
  These guidelines were developed to promote high technical quality and Agency-wide consistency in the process of assessing the potential health effects impacts of human exposure to environmental contaminants.

Air Pollutants
Aerosols, Asbestos, Carbon Monoxide, Chlorofluorocarbons (CFCs), Criteria Air Pollutants, Ground Level Ozone, Hazardous Air Pollutants (HAPs), Hydrochlorofluorocarbons (HCFCs), Lead, Mercury, Methane, Nitrogen Oxides (NOx), Particulate Matter (PM), Propellants, Radon, Refrigerants, Sulfur Oxides (SOx), Volatile Organic Compounds (VOCs)

Biological Contaminants

Carcinogens

Chemicals
Benzene, Chlorofluorocarbons (CFCs), Chromated Copper Arsenate (CCA), Dichloroethylene (DCE), Dioxins, Endocrine Disruptors, Ether, Ethylbenzene, Furans, Halons, Hazardous Air Pollutants (HAPs), Heavy Metals, Hydrochlorofluorocarbons (HCFCs), Inorganic Cyanides, Ketones, Methane, Methyl Bromide, Methyl Chloride, Methyl-T-Butyl-Ether (MTBE), Nitrogen Oxides (NOx), Organic Cyanides, Particulate Matter (PM), Perchloroethylene (PCE), Phthalates, Polychlorinated Biphenyls (PCBs), Radionuclides, Styrene, Sulfur Hexafluoride (SF6), Sulfur Oxides (SOx), Toluene, Trichloroethylene (TCE), Volatile Organic Compounds (VOCs)

Microorganisms
Coliform, Cryptosporidium, Viruses

Ozone

Radiation
Ionizing Radiation, Radiation Detection, Radiation Exposure, Radiation Protection, Radionuclides, Radon

Soil Contaminants
Acetone, Arsenic, Barium, Benzene, Cadmium, Chloroform, Cyanide, Lead, Mercury, Polychlorinated Biphenyls (PCBs), Tetrachloroethylene, Toluene, Trichloroethylene (TCE)

Toxic Substances
Persistent Bioaccumulative Toxic Pollutants (PBTs), Persistent Organic Pollutants (POPs), Toxicological Profiles

Water Pollutants
Arsenic, Contaminated Sediment, Disinfection Byproducts, Dredged Material, Lead, Microbial Pathogens