Henry John Horstman Fenton (18 February 1854 – 13 January 1929) was a British chemist who, in the 1890s invented Fenton's reagent, a solution of hydrogen peroxide and an iron catalyst that is used to oxidize contaminants or waste waters. Fenton's reagent can be used to destroy organic compounds such as trichloroethylene (TCE) and tetrachloroethylene (PCE).