Chlordan is a non-planar molecule and thus can adsorb onto a catalyst surface in a range of orientations. Thus catalytic removal of chlorine atoms must be a stepwise process. Incomplete dechlorination is thus to be expected and is indeed found in many cases. However catalysis of Chlordan over a 5 % platinum catalyst at 200° removes all chlorine atoms to yield tetrahydrodicyclopentadiene. For a palladium catalyst the major product appears to be a mono-chloro species. These results represent a significant simplification over that achieved when a Ni2B catalyst is used, from which reaction a pentachloro species results. Thus it has been shown that Chlordan can be rapidly and easily resolved from other complex polychlorinated species by hydrodechlorination.