Update: The Fresno Fire Department has concluded the explosion and fire were the result of a marijuana "Honey Oil" operation.
Honey Oil is the process of extracting THC through the use of a homemade pipe with pressurized butane to force residue "Honey Oil" from marijuana stems, which is then smoked.
Investigators say the process results in dangerous amounts of flammable vapors, which ignited to cause the explosion.
The injured man, in his late 20s, received 2nd and 3rd degree burns over 80% of his body and is listed in serious condition at Community Regional Medical Center.
One person is recovering after an explosion and fire at an apartment complex in Fresno's Tower District.The fire happened around 9:30 p.m. Monday night near Harrison and Olive.Firefighters found a man with severe burns on the front yard of the complex, and flames shooting out of a second story window.Investigators are trying to determine if the explosion came from the fire or if it was the cause.The Red Cross is helping those displaced by the fire.