Charles J. Spiegl was a civilian scientist employed by the Manhattan Project. He was involved in radiation toxicology, studying the effects of radiation on animals at the Trinity Site near Alamogordo, New Mexico. He also participated in the postwar nuclear tests at Bikini Atoll in the Marshall Islands, where he was assigned to Task Group 1.1.2 on board the USS Haven, specifically moderating radiation safety after the explosions. In the early 1950s, he was transferred to the nuclear programs at Groom Lake Air Force Base in Nevada.
Information contributed by his daughter, Barbara Spiegl Gibson.