Toluene is a pollutant from petroleum refineries and a chemical used in plastics manufacturing as well as the pharmaceutical, paint and furniture industries.

trans-1,2-Dichloroethylene is a synthetic chemical used as a solvent, refrigerant, and in the production of pharmaceuticals; it is released as pollutant from various industrial chemical factories.

Trichloroethylene is used to remove grease from fabricated metal parts and in the production of some textiles; this pollutant comes from metal degreasing sites, metal finishing and rubber processing industries.

Trihalomethanes constitute the sum of four disinfection byproducts: chloroform, bromodichloromethane, dibromochloromethane, and bromoform.