At 10:52 A.M. on July 29, 1967 the second launch was being readied when a Zuni rocket accidentally fired from an F-4 Phantom parked on the starboard side of the flight deck aft of the island. The missile streaked across the deck into a 400 gallon belly fuel tank on a parked A-4D Skyhawk. The ruptured tank spew highly flammable JP-5 fuel onto the deck which ignited spreading flames over the flight deck under other fully loaded aircraft ready for launch. The ensuing fire caused ordnance to explode and other rockets to ignite. Spread by the wind, the flames engulfed the aft end of the stricken ship turning the flight deck into a blazing inferno.. Berthing spaces immediately below the flight deck became death traps for fifty men, while other crewmen were blown overboard by the explosion.
The fire was caused by a "huffer" , a vehicle with a gas turbine compressor built into it being parked with the exhaust of the compressor under the rocket motor.
The huffer is plugged into the jet engine of aircraft and provides the air flow to start the jet engine. Being a jet engine itself, it's exhaust is VERY hot.