Missile Complexes Soviet Premier Nikita Khrushchev fully exploited fears of a "missile gap," even as Congress poured money into the arms race. In the late 1950s and the early 1960s, Utah Construction & Miningbuilt missile silos and command centers at Air Force bases in Colorado, Montana, North Dakota, Wyoming, and Kansas, as well as playing a major role in excavating and building the North American Air Defense Command Base (NORAD) in Colorado. During World War II, the Rocky Mountain Arsenal in Commerce City, Colorado, had operated as a primary producer of nerve gas, napalm, mustard gas, and other chemical weapons. In the late 1950s and early 1960s propellants for the Titan missile programs were mixed at the arsenal, as were propellants for the space program. Utah Construction & Mining installed a scrubber, exhaust fans, and a stack (seen at left) for a missile launching facility. Later, the Rocky Mountain Arsenal would undergo massive restoration of soil and ground water to become a National Wildlife Reserve.