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.
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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.