👉 In the context of environmental science, "fumigant" refers to a chemical substance that is used as an insecticide or to control pests. These substances are typically derived from organic compounds and are highly toxic to certain types of insects. Examples of fumigants include pyrethrin, which is used in pesticides such as permethrin and pyrethrins; diazinon, which is commonly used in insecticides; and dieldrin, a fungicide that is used