A medical supplies warehouse burst into flames, going up in a matter of minutes, as a new video from inside the San Joaquin facility shows just how quickly the situation got out of hand.

A video taken by an employee shows a small fire burning and quickly spreading on top of the Medline warehouse’s shelving. It’s unclear what started the fire.

The small blaze would go on to rapidly spread across the roof and engulf the entire facility within 30 to 40 minutes, Tracy Fire Chief Randall Bradley said.

The massive medical supplies warehouse is still burning Friday, sending a plume of black smoke into the sky and debris into surrounding neighborhoods. Dozens of chunks of what appeared to be charred styrofoam landed in a nearby dog park, according to KCRA.

Fire officials said in a Friday press conference that managing the fire has been “very challenging” because of its massive size, comparable to a “skyscraper lying on its side.”

Because of the fire’s huge size, first responders expect to be in the area quelling the blaze for days.

“A 1 million-square-foot fire is an extremely rare fire, not only in California but in the United States, and so, this is a unique fire for us and we expect to be here for a couple of days,” Bradley said.  

The lack of an operating sprinkler system inside the facility also worsened the situation.

“We had a good, aggressive interior fire attack, and the sprinklers were not operating, so we’ll have to find out what happened to the water supply,” Bradley said.

“Things worked against us,” he added. “Again, water supply issues, low humidity, high winds and high temperatures. It was a little bit of the perfect storm for this fire evolving quickly.”

The fire suppression systems for the warehouse had been inspected in January, but it’s unclear why they no longer work.

The Tracy blaze also spread to nearby big rigs and a large pile of pallets near a Fedex facility to the south, but fire crews contained the offshoot fire.

The City of Tracy has declared a local state of emergency as protective measures are advised for certain adults sensitive to the contaminated air.

No injuries have been reported, which is a thankful note for first responders.

“It’s going to take a little while, but as long as nobody’s hurt, we can fix everything else,” Tracy Police Sgt. Michael Richards told CBS News.