Fresno firefighters say the man is in the burn center with life-threatening burns. They believe that the man may have been making honey oil hash, which they say is a very dangerous and volatile process.
"Our estimate approximately 80 percent of his body between 2nd and 3rd degree burns," Fresno Fire Batallion Chief Rich Cabral said.
Firefighters said it looks like the fiery accident may have been a result of the man attempting to make honey oil, derived from marijuana.
"Honey oil is used as a smoking product that's very similar to hashish," Cabral said.
Authorities say making honey oil involves extracting a chemical from marijuana with the use of butane gas.
"The very process is highly dangerous and in this case, as others we've seen, explosions happen inside the home where other people have been injured," Cabral said.
Firefighters say a woman and two children were inside the house in different room when the explosion occurred. All were uninjured.
Sabrina Valenzuela lives a few homes down the street-she says she heard a loud noise earlier in the evening while she was watching television inside her house.
"I heard a big bang and the door was shaking like it was an earthquake but we didn't think anything of it-with the train tracks being so close," neighbor Sabrina Valenzuela said.
After hearing what happened just a few doors down from her home Valenzuela said she doesn't know what to think
"It's just too close to home. It doesn't matter where you live, you gotta be careful about your neighbors," Valenzuela said.
Firefighters said they are trying to determine if the people lived in the home or were squatting. Police are trying to contact the owner of the property.