The fire began some time before midnight at the Alco Metal & Iron Company, near Highway 37.
Check out this huge warehouse fire that lit up last night in Vallejo. Embers from it even started several grass fires pic.twitter.com/8FCURtrovd— Amy Hollyfield (@amyhollyfield) August 21, 2015
The fire was so big that a decision was made not to even try to go inside. That turned out to be a good decision since the roof collapsed soon after fire crews arrived.
The area is so dangerous that investigators will not be allowed inside until Monday.
Firefighters are also worried about what was burning inside the metal recycling warehouse, and the air that fire crews and locals are breathing.
"There are canisters of used oil propane tanks, a couple of pallets of lead batteries they were recycling," explained Vallejo Fire Battalion Chief Cliff Campbell.
The large flames and orange smoke above the fire could be seen for miles around the Bay Area. The sights and smells attracted residents to come out and see what was going on.
"It smells like burning rubber and chemicals. It stinks!" said Vallejo resident Melinda Garaly.
"My first concern is my children. It's horrible to think about being exposed to something that could possibly harm us. We are gonna do our due diligence and stay out the air as much as we can," said Burgundie Spears, also a Vallejo resident.
Investigators say the wind is helping to move the bad air out of the area.
Firefighters expect flare-ups to continue through the day and possibly into the weekend.
People are being asked to avoid the area. A shelter-in-place order was not issued, but firefighters advised nearby residents to keep windows closed and be vigilant.
A fire in the yard of the Alco Metal & Iron Company occurred on Aug. 22, 2014.
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