Investigators are looking into why a sprinkler system failed to activate during the massive fire that destroyed Medline’s distribution warehouse in Tracy. Nearly 24 hours after the fire began, smoke continued to billow from the remains of the 1 million-square-foot facility, which served as Medl ine’s main distribution center for medical supplies across the western United States. According to the Tracy Fire Department, the warehouse’s sprinkler system had been tested and signed off in January. However, when firefighters arrived at the facility shortly after 1 p.m. Thursday, there was no indication the sprinklers had activated. Officials said the fire marshal checked the fire pump room, which supplies water to the sprinkler system, and found a reading of zero. “We knew there was no water flowing,” Deputy Chief Brian Bagley said. “That fire pump also supplies the yard hydrants directly adjacent to the facility itself. So we had limited to no water coming out of those hydrants.” Bagley said firefighters were forced to connect to the municipal water system outside the property and lay hose lines as long as 1,600 feet to battle the flames. Despite those efforts, Tracy fire officials said the warehouse was fully engulfed within about 40 minutes, forcing crews into a defensive firefighting strategy. Fire officials described the blaze as one of the largest warehouse fires of its kind in the country. The facility had recently undergone a $500 million upgrade that included robots powered by lithium-ion batteries, which continue to burn inside the structure. Thursday’s hot and windy conditions also carried embers more than two miles away, sparking grass fires and another fire at a nearby FedEx facility. Firefighters were able to save the FedEx building. Authorities have called in the Bureau of Alcohol, Tobacco, Firearms and Explosives to assist with the investigation. Officials said it could take several days before the structure cools enough for investigators to safely enter and determine the cause of the fire. Residents living near the smoke are being urged to shelter in place as firefighting operations continue. Fires 22 hours ago Massive fire destroys medical supply warehouse, sparks evacuations in Tracy Fires 13 hours ago Massive fire destroys medical supply warehouse in Tracy Fires 14 hours ago Tracy Fire Department chief on massive fire that destroyed warehouse ...read more read less