We speculate that someone smelled the gas leak when they awoke, and fiddled with the (burner) knobs, which created a spark.

When you've got a major gas leak like that everybody working around it has to turn their radios off and everything else off because any kind of little spark would ignite it.

This is something very, very different for them. One of them asked 'what is that?' when they smelled fertilizer on the bus ride.

We either didn't have enough gas left or they made plays.

They smelled bad

We're still talking. Though we want to get it finished soon, I just can't speculate on when it's going to be.