(E)-Tetrachlorovinphos is an (E)- isomer of Tetrachlorovinphos. Tetrachlorovinphos is an organophosphate cholinesterase inhibitor that is used as an insecticide. Tetrachlorvinphos was introduced and first used commercially in 1966 in the USA. Tetrachlorvinphos was originally registered for use on various food crops, livestock, pet animals. Tetrachlorvinphos is applied dermally to livestock to control flies and mites. It is used as an oral larvicide in cattle, hog, goats and horses; in cattle ear tags to control flies; in cattle feedlots; in poultry dust boxes to control poultry mites; and in poultry houses. Tetrachlorvinphos also is used in pet sleeping areas and pet flea collars and to control flies around refuse sites, recreational areas, and for general outdoor treatment. Tetrachlorvinphos can cause cholinesterase inhibition in humans; that is, it can overstimulate the nervous system causing nausea, dizziness, confusion, and at very high exposures (e.g., accidents or major spills), respiratory paralysis and death. In 2014, the Natural Resources Defense Council (NRDC) filed a lawsuit against the United States Environmental Protection Agency (EPA) seeking EPA to respond to NRDC’s 2009 petition to ban tetrachlorvinphos in common pet flea treatment products. Tetrachlorvinphos is reportedly registered for use in Canada, South Africa, and Australia.