On the `` Mont-Blanc '' , the impact Influence damaged Damaging benzol barrels stored on deck , leaking Motion vapors which were ignited Process_start by sparks from the collision Catastrophe , setting off a fire Catastrophe on board that quickly grew out of control .

Two 15,000-ton refrigerated ammonia storage tanks were ruptured Destroying , releasing liquid ammonia and ammonia vapors which forced Request the evacuation of 1,700 residents from the surrounding area .

A subsequent Naval Board of Inquiry never determined Deciding the exact cause of the disaster but concluded Process_end that the initial explosion was caused Causation when a mortar round aboard detonated Attack during an unloading operation because it was either dropped Motion_directional or went off when gasoline vapors ignited .

The report 's conclusion was that the probable cause Causation of the accident was explosion Attack of flammable fuel vapors in the center fuel tank .