Fire has ravaged a large industrial building close to homes in Los Angeles County but no injuries were reported.
"There's some sort of a narcotics laboratory inside that structure," Capt. Tony Imbrenda of the LA County Fire said. "As far as what type of narcotic -- or what the process was, going on -- that's still being determined right now."
Several explosions occurred as the structure burned in the 7300 block of Somerset Boulevard in Paramount late Monday morning.
Los Angeles County firefighters arrived at the scene quickly after receiving the fire report at 10:41 a.m.
Spokesman Marvin Lim says the fire was contained around 11:24 a.m. but firefighters continue to put out remnants of the fire.
Investigators have not yet determined how the fire began or what caused the explosions.
Witnesses said a chemical-filled stench permeated the air long after the fire was extinguished.