At least 11 firefighters were injured while responding to a downtown Los Angeles fire, Los Angeles Fire Department Capt. Erik Scott said.
More than 230 firefighters responded to the scene where multiple buildings had caught fire, according to the department.
The department had issued a 'Mayday' distress call around 6:30 p.m in a neighborhood near Little Tokyo and Skid Row after what Scott said was a 'significant' explosion in a single story commercial building.
Firefighters had already begun making entry in the building at the time of the explosion after they saw smoke coming out.
A medical branch was quickly established to treat and transport injured firefighters to the hospital. Scott did not say how severely the 11 firefighters were injured.
The blaze has since been extinguished and there is an active investigation into what may have been the cause, he said.
The fire may have begun at Smoke Tokes Wholesale Distributor -- a supplier for those who produce butane honey oil, the department said.
Sean Miura, who captured video of the blaze, told CNN he smelled burning and smoke before hearing a loud explosion that was followed by falling ash and large debris.
'I wasn't close enough to determine if anyone was harmed but am concerned for the unhoused residents in the area and the neighboring residents in the senior/low-income housing as the air quality was affected for blocks,' he said.