The blaze that started aboard the USS Bonhomme Richard in San Diego Sunday morning is still raging, and has brought down the ship’ forward mast, causing extensive damage to the ship’s superstructure. More than 400 sailors are working to put out the massive fire, and Navy officials said that currently only 2 decks are standing between the fire and the 1 million gallon of fuel present on the vessel.
Can't say for sure but probably heat, oxygen, some sort of fuel, and a catalyst.