This report from a local news station shows high contents of oil and petroleum in the water, and at around the 3:00 minute mark you see that the independent lab they use for testing make the startling claim that the water sample from one area exploded during testing. It could be due to a dispersant or, ominously, methane in the water. Some theorize that a methane gas bubble triggered the disaster in the first place, leading to some of the more hysterical parts of the web to claim that so much methane is being released a giant fireball is bound to happen. And I mean giant.

And this may bolster their argument: