Pentachlorobenzenethiol is a chemical compound from the group of thiols and organochlorine compounds. Wastewater may also be polluted with organochlorine compounds. Chloride is an ideal group due to the low cost of organochlorine compounds. This allows residues, especially of organochlorine pesticides, to accumulate in their systems. The use of chlorine dioxide minimizes the amount of organochlorine compounds produced. A number of organochlorine pesticides have been banned from most uses worldwide. The largest application of organochlorine chemistry is the production of vinyl chloride. Bleaching with chlorine produces large amounts of organochlorine compounds, including dioxins. This strategy also addresses how Australia will manage HCB waste and organochlorine pesticides. A 2004 study, reported in "Science", analysed farmed and wild salmon for organochlorine contaminants. Many organochlorine compounds are biosynthesized in this way. Endosulfan is an off-patent organochlorine insecticide and acaricide that is being phased out globally. Organophosphorus or organochlorine compounds may be used, usually in a spraying formulation. Like most organochlorine compounds, chloroethanol combusts to yield hydrogen chloride and phosgene. The two main groups of organochlorine insecticides are the DDT-type compounds and the chlorinated alicyclics.