Hydrogen peroxide
Fenton's reagent (hydrogen peroxide catalyzed with iron) and potassium permanganate are the oxidants that have been used the longest, and are now used the most widely. The systems of using hydrogen peroxide were based on the work of H.J.H. Fenton, who used iron salts to catalyze the compound. Hydrogen peroxide was first used in 1985 to treat a formaldehyde spill at Monsanto's Indian Orchard Plant in Springfield, Massachusetts. At this site, a 10% solution of hydrogen peroxide was injected into a formaldehyde plume. Fenton's reagent was initially used to treat hydrocarbon sites where benzene, toluene, and ethylbenzene were present.