?Chlorpyrifos , its cas register number is 2921-88-2. It also can be called O,O-Diethyl O-3,5,6-trichloro-2-pyridyl phosphorothioate ; Phosphorothioic acid O,O-diethyl O-(3,5,6-trichloro-2-pyridinyl) ester ; Chlorpyrifos-ethyl ; Chlorpyritos ; Clorpyrifos ; Dursban HF ; Eradex ; Lorsban 4E-SG ; Pyrinex ; Super I.Q.A.P.T. ; Trichlorpyrphos ; and Dowco 179 .