Toxic (also called hazardous) air pollutants are those that are known or suspected to cause cancer or other serious health effects, such as reproductive effects or birth defects, or to cause adverse environmental effects. The degree to which a toxic air pollutant affects a person's health depends on many factors, including the quantity of pollutant that the person is exposed to, the duration and frequency of exposures, the toxicity of the chemical, and the person's state of health and susceptibility.

The 1990 Clean Air Act Amendments list 188 Hazardous Air Pollutants (HAPs) that the United States Environmental Protection Agency (EPA) is required to control. (The list originally included 189 chemicals. Based on new scientific information, the EPA removed caprolactam from the list in 1996; thus, the current list includes 188 pollutants.) Examples of toxic air pollutants include benzene, which is found in gasoline; perchloroethylene, which is emitted from some dry cleaning facilities; and methylene chloride, which is used as a solvent and paint stripper by a number of industries. Examples of other listed air toxics include dioxin, asbestos, toluene, and metals such as cadmium, mercury, chromium, and lead compounds. Note: This information was taken from the EPA website www.epa.gov/air/oaqps/takingtoxics.

Following is a list of the air toxic pollutants monitored in Jacksonville by the Mobile Air Toxics Laboratory and at the stationary air toxics monitoring sites. Twenty-seven of these pollutants are considered HAPs according to the EPA 1990 Clean Air Act Amendments (Note: HAPs are indicated in red):

Dichlorodifluoromethane (Freon 12)
Chloromethane
1,2-Dichloro-1,1,2,2-Tetrafluoroethane (Freon 113)
Vinyl chloride
Bromomethane
Chloroethane
Trichloromonofluoromethane (Freon 11)
1,1,2-Trichloro-1,2,2-Trifluoroethane (Freon 114)
1,1-Dichloroethene
Dichloromethane
1,1-Dichloroethane

Cis-1,2-Dichloroethene
Chloroform
1,1,1-Trichloroethane
Benzene
1,2-Dichloroethane
Carbon Tetrachloride
Trichloroethene
1,2-Dichloropropane

Cis-1,3-Dichloropropene
Trans-1,3-Dichloropropene
Toluene
1,2-Dibromoethane
1,1,2-Trichloroethane
Tetrachloroethylene
1,2-Dichlorobenzene
Chlorobenzene
Ethylbenzene
Meta/Para-xylene
Styrene
Ortho-xylene
1,1,2,2-Tetrachloroethane

1,3,5-Trimethylbenzene
1,2,4-Trimethylbenzene
Alpha-chlorotoluene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
1,2,4-Trichlorobenzene
Hexachlorobutadiene