PHOTOS: Nine firefighters are injured, including two who are in critical condition, following an explosion in Los Angeles, according to the LA Fire Department.
The blast occurred six minutes after 10 firefighters arrived on scene responding to a semi-truck on fire early Thursday, the department said.
The semi-truck does "not run on diesel or on gasoline, but it is actually propelled ... with compressed natural gas," Fire Department Capt. Erik Scott said at a news conference. Two 100-gallon tanks were on the truck, one of which exploded while firefighters were putting out the blaze, Scott said.
The flames were as high as telephone poles and exploded a transformer nearby, he said. Two firefighters were critically hurt, four suffered moderate injuries and three had minor injuries, Scott said.