A massive fire erupted at a cold storage facility in the Boyle Heights neighborhood of Los Angeles on Wednesday, forcing city officials to issue shelter-in-place orders for nearby residents. The blaze engulfed the solar panel-covered roof of the 500,000 square foot warehouse owned by Lineage, sending thick clouds of dark smoke and ammonia into the air.
About 110 firefighters from the Los Angeles Fire Department responded to the afternoon fire, joined by hazmat teams from both the city and Los Angeles County. Firefighters initially attempted to extinguish the flames using hand lines on the roof, but were forced to retreat after an ammonia refrigeration line burst. "At some point, an ammonia line was compromised and we had a large, pressurized off-gassing of ammonia," LAFD Chief Jaime Moore told NBC News 4.
Cold storage facilities use ammonia as a cost-effective refrigerant, but the chemical is both toxic and flammable. The dangerous conditions prompted Mayor Karen Bass to urge residents in the affected area to stay indoors immediately, close windows and doors, turn off air conditioning, and avoid unnecessary travel to the area.
The fire grew so large and hazardous that firefighters took the unusual step of deploying helicopters to battle it from above. At least three helicopters delivered more than half a dozen water drops onto the burning roof while firefighters evacuated the immediate area. "The amount of fire that they had was overrunning the amount of water we were able to put on it and our firefighters had to evacuate the area for a few minutes there while it was off-gassing," Moore said.
Chief Moore warned residents with health conditions to avoid breathing the contaminated air by remaining indoors with windows closed and air conditioning turned off while the city monitored air quality for ammonia off-gassing.
By evening, the roof fire had been largely contained, though the roof showed signs of sagging. The presence of solar panels on the building raised additional concerns about potential lithium ion batteries used to store solar energy. These batteries can undergo "thermal runaway," a process that makes them extremely difficult to extinguish.
"It's extremely hard to fight the fire, it's dangerous to be around the fire, and it's dangerous to be around the extremely hazardous smoke," said Jennifer Middleton, an LAFD spokesperson, regarding lithium ion battery fires. Moore called these batteries "one of our newest challenges in the fire service."
Authorities have not yet disclosed the cause of the fire. Lineage did not immediately respond to requests for comment about the incident.