Caught on video: unbelievable dryer explosion wrecks laundromat and narrowly misses customer. Can you guess what caused the blast?

People online are trying to figure out what made this laundromat dryer explode with such force that it knocked out the front of the building. The security camera footage shows a customer leaving the laundromat. A few seconds later, one of the dryers, which had been tumbling a load of clothes, blows up in a fiery explosion. He probably would have been killed in the blast if he'd lingered a bit longer.

Twitter has been awash with speculation regarding the cause of the explosion. Among the suggested culprits are lint, lithium batteries, shotgun shells, C4, grease-saturated clothes, gas leaks, and even a butane lighter. What's your guess?