Tracy warehouse fire among largest in US, crews battle for days

A million-square-foot Medline distribution center in Tracy burned so intensely that fire officials said it may rank among only three or four warehouse fires of similar size in U.S. history. The blaze, which broke out just before 1 p.m. Thursday on the 5700 block of Promontory Parkway, quickly turned a quiet industrial complex west of downtown Tracy into a test of how the state handles massive warehouse fires.

The building was fully engulfed within about 30 minutes, officials said, and neighboring commercial structures and nearby fulfillment centers were evacuated as the fire spread through the industrial park. All 120 employees on site got out safely, and no injuries were reported, a crucial outcome at a facility tied to about 900 workers.

What made the fire so hard to contain was not just its size but the conditions inside and around it. Officials said the sprinkler system did not activate, and the facility’s hydrants lacked water pressure, while city hydrants outside the site worked properly. High winds, low humidity and hot temperatures helped drive the flames, and firefighters also had to contend with hazardous materials inside the warehouse, including hundreds of lithium-ion-powered robots.

Crews were pouring in about 4,000 gallons of water per minute, and officials said they had used about 1 million gallons in the previous 10 hours. That kind of water demand underscores why a blaze in a building this large can keep burning for days, even with a heavy response. Authorities said the operation was expected to continue for several days.

The fire also raised immediate health and safety concerns beyond the property line. Tracy officials were monitoring air quality, planning street sweeping for debris, and warning residents not to touch fallen material because it could be hazardous. The concern was not only smoke drifting through the Bay Area and San Joaquin County, but also the possibility that debris from the roof and warehouse contents could pose a risk long after the main flames are knocked down.

The stakes are bigger than one building. Medline is a major medical supply manufacturer and distributor, and the loss of the Tracy facility could disrupt hospital and healthcare deliveries across the western United States. Officials said the fire started on the roof, but the formal cause remained under investigation as crews kept working through one of the most unusual warehouse fires the region has seen.