First responders are on the scene at a massive commercial fire that broke out in Tracy on Thursday afternoon.

The blaze erupted at the Medline facility, the South San Joaquin County Fire Authority said on social media. The million-square-foot warehouse is at 5701 Promontory Parkway, according to a statement posted by the city. As of 3 p.m., a second warehouse was “being threatened,” the fire authority said. Multiple agencies had responded at that time, including Stockton Fire, DLA, Mountain House Fire, Lathrop-Manteca Fire and Manteca Fire.

Aerial footage shows plumes of black smoke in the sky. Police officers arrived around 1:40 p.m. and closed Promontory Parkway, according to the Tracy Police Department. Police said they are aware of “multiple fires in the area” and are coordinating with the emergency personnel to close roads and coordinate any necessary evacuations. There was no threat to residents as of 2:45 p.m., the department said.

Tracy Fire Chief Randall Bradley said in a briefing Thursday afternoon that sprinklers in the facility were not operating and that there was no water pressure on fire hydrants inside. He said the reason for the non-operating equipment was not known.

Medline describes itself as the “largest provider of medical-surgical products and supply chain solutions serving all points of care” on its website. In a posted statement, Medline confirmed that “All Medline employees and on-site personnel are safe and accounted for.”

“We are coordinating closely with local authorities and first responders as we assess the fire’s impact and will share more details as they become available,” the Illinois-based company wrote.

In an update at 7:05 p.m., the South San Joaquin County Fire Authority said “crews remain on scene with an estimated total of 200 fire personnel, and approximately 100 additional support personnel to cover multiple incidents in the area,” including a fire that erupted at the nearby FedEx warehouse, with pallets and multiple big rig trailers catching fire.