On January 31, 1967, four days after the Apollo1 fire, United States Air Force airmen William F. Bartley Jr. and Richard G. Harmon were killed in a flash fire while tending laboratory rabbits in the Two Man Space Environment Simulator, a pure oxygen chamber at the School of Aerospace Medicine at Brooks Air Force Base. Like the Apollo1 fire, the School fire was caused by an electrical spark in a pure oxygen environment. The widows of the Apollo1 crew sent condolence letters to Bartley and Harmon's families.