A fumigant is "a pesticide in vapor or gaseous form used to kill pests or disinfect materials." [NTP] Fumigants comprise a large variety of different chemicals that readily diffuse through air, and some can also penetrate soil, skin, and protective equipment. Of the fumigants covered in the EPA handbook, "Recognition and Management of Pesticide Poisonings," many are respiratory irritants and some can induce pulmonary edema. Some are asphyxiants, and some are central nervous system depressants:
CHEMICAL ASPHYXIANTS: acrylonitrile*, hydrogen cyanide*;
HALOGENATED HYDROCARBONS: carbon tetrachloride*, chloroform*, ethylene dichloride*, dibromochloropropane*, dichloropropene, dichloropropane*, ethylene dibromide*, methyl bromide, methylene chloride*, p-dichlorobenzene;
OXIDES & ALDEHYDES: acrolein, ethylene oxide, propylene oxide, formaldehyde, paraformaldehyde;
OTHERS: carbon disulfide*, chloropicrin, naphthalene, phosphine (aluminum, magnesium, and zinc phosphide), sulfur dioxide, sulfuryl fluoride;
* No longer used as fumigants in the U.S. [EPA Pesticides]
Chloropicrin is a lacrimator that is often added to fumigants with poor warning properties. [AHLS, p. 264] In urban pest control operators in Australia, fumigation gases include carbon disulfide, chloropicrin, ethylene oxide, and methyl bromide. Methyl bromide is being phased out for environmental reasons. See Hyperlink.