It is speculated Powell developed cancer as a result of his participation in the film The Conqueror, which was filmed at St. George, Utah, near a site used by the U.S. military for nuclear testing. About a third of the actors who participated in the film developed cancer, including Powell, who directed the film, John Wayne, Susan Hayward and Agnes Moorehead. However, in a 2001 interview with Larry King, Powell's widow June Allyson stated that the cause of death was lung cancer due to his chain smoking.
