Arson suspected in massive warehouse fire in Southern California

A massive fire at a warehouse in Southern California is being investigated as arson, and a person of interest has been taken into custody, according to officials.

The fire broke out at about 12:30 a.m. Tuesday at a Kimberly-Clark warehouse in Ontario, east of Los Angeles, near Hellman and Merrill avenues. More than 140 firefighters responded as flames tore through the 1.2 million-square-foot facility.

Ontario Fire Department Deputy Chief Mike Wedell said the fire spread quickly and engulfed the building’s entire interior.

Wedell said investigators quickly determined the fire was suspicious and began investigating it as arson. He said the person in custody is a man and that the investigation is ongoing.

“There was a person of interest identified from the very initial response of this incident,” he said. “That individual was identified, was taken into custody and has been taken to the Ontario Police Department.”

Firefighters were battling the blaze in defensive mode, meaning crews were working from the outside to contain it and keep it from spreading rather than going inside the structure. San Bernardino County Fire said the incident reached six alarms and added that the warehouse contained paper products.

“We are fortunate that we’ve been able to contain the fire to the building, so there is no threat of the fire spreading to nearby buildings, businesses or residences,” Wedell said.

All employees inside the warehouse got out safely and no injuries were reported.

Officials said smoke and ash were affecting air quality in the area and urged residents to avoid the area and stay out of the smoke, with children and older adults advised to remain indoors if possible.

As of 4 p.m. local time on Tuesday, the fire was still burning but remained contained to the building.

The Ontario Fire Department is battling a 6 alarm warehouse fire. The building contains paper products. Units from many neighboring departments are on scene supporting the suppression efforts. pic.twitter.com/KLNykaMbgY

— San Bernardino County Fire (@SBCOUNTYFIRE) April 7, 2026