Dioxane
(also diethylene dioxide, diethylene ether, diethylene oxide) (not to be confused with DIOXIN)
Dioxane is a solvent classified by the EPA as a probable human carcinogen, and some research suggests that it may suppress the immune system. Dioxane is listed in the 1990 Clean Air Act as a hazardous air pollutant and is on the EPA's Community Right-to-Know list.
Found in: Conventional window cleaners and is an impurity in some ethoxylated surfactants.