mirex

A white odorless crystalline solid, C₁₀Cl₁₂, formerly used as an insecticide against ants and as a fire retardant. It was banned in the United States in 1978 because of its effects on the environment and possibly on human health.

The pesticide and fire retardant perchloropentacyclodecane that is a persistent, bioaccumulative, and toxic pollutant