25 July 1962 – “The third launch attempt of a nuclear warhead in Operation Fishbowl, as part of Operation Dominic, aboard an Douglas SM-75 Thor IRBM, 58-2291, vehicle number 180, from Johnston Island in the Pacific Ocean, named Bluegill Prime. After the 2 June 1962 failure of the first attempt, Bluegill, also fails when, due to a sticking valve, the Thor missile malfunctions after ignition of the rocket engine, but before leaving the launch pad.
The range safety officer destroys the nuclear warhead by radio command with the missile still on the launch pad. The vehicle then explodes, causing extensive damage in the area of the launch pad. Although there was no danger of an accidental nuclear explosion, the destruction of the nuclear warhead on the pad causes extensive contamination of the area by alpha-emitting radioactive materials. Burning rocket fuel, flowing through the cable trenches, causes extensive chemical contamination of the trenches and the equipment associated with the cabling in the trenches. The radiation contamination on Johnston Island is determined to be a major problem, and it is necessary to decontaminate the entire area before the badly damaged launch pad can be rebuilt. Further launch operations will not resume until 15 October 1962. Although, by definition, this qualifies as a Broken Arrow incident, this test is rarely included in lists of such mishaps.” (1)
Source: (1) https://en.wikipedia.org/wiki/Portal:Aviation/Anniversaries/July_25