A criminal probe has been launched into an explosion in downtown Los Angeles on Saturday that left multiple buildings on fire and 11 firefighters injured, The Los Angeles Times reports. Federal and local officials are reportedly investigating whether butane hash oils produced at a warehouse distributor dubbed Smoke Tokes might have started the blaze. The Los Angeles Fire Department said the firefighters were hurt after responding to a “significant explosion,” which erupted while they were inside a building reported to have a fire. “We are looking at every aspect at this stage. We haven’t determined a cause,” said LAPD Assistant Chief Horace Frank. They are all expected to survive their injuries, according to a LAFD spokesperson. More than 230 firefighters were sent to try and tackle the fire, located in the 300 block of East Boyd Street. The explosion sent flames shooting up into the air that could reportedly be seen from miles away.