My theory is called the "3 morons theory"
One moron was running through the ship with nitroglycerin (bad heart you see), he slammed into another moron who was covered in sodium carbonate (don't ask, the captain was kinky)
The third moron was a 1%er who flicked his cigar nub at the 2 poor rabble running in the ship.
Kaboom!
Who needs the Mythbusters, you got me.
(honestly makes more sense than a German sub, just saying)