The blast produced a mushroom cloud underneath a Los Angeles I-10 that nearly engulfed a man who appeared to be moving debris from the fire, according to a video posted by a passerby later that morning.
"After things starting exploding, I was outta there," the driver said. "I often fear that I could possibly see a tragedy like this."
Authorities cleaned up the encampment later that day, but two days later the driver said it was "packed full with new homeless."
He hoped the video could show how "fragile and dangerous" the homeless situation is getting in the city.
Fire authorities said it's not their protocol to investigate what caused the blaze because it didn't result in injuries or damage any property.
The driver was reportedly the first to alert authorities around 6:30 a.m. that morning.