According to Contra Costa County Fire Protection Capt. Robert Marshall, the fire was reported at a warehouse in the 2300 block of Stanwell Drive near the Buchanan Field Airport around 12:30 a.m.
He says a haze of smoke and the smell of burning plastic were reported throughout central Contra Costa County and as far away as Oakland.
Contra Costa Health Services has advised people living within half a mile of the warehouse who have pre-existing respiratory conditions to avoid the area or stay indoors and close windows and doors.
Fire officials advised a nearby dialysis clinic to close for the day.
The fire was declared under control at about 2:45 a.m. The health advisory was lifted around noon.
The captain says fire crews have been taking a defensive approach to fighting the blaze in order to keep firefighters out of harm's way.
According to Marshall, the warehouse is over 50,000 square feet and serves as the storage and recycling site of a telephone supply company that installs and recycles commercial telephone systems.
Marshall said the fire is burning "a lot of plastics, a lot of wire" and that while no official order has been issued, "anyone who can smell the smoke should shelter in place."
He said the smoke and smell of burning plastic is likely to linger well into the afternoon.
No injuries have been reported.
A homeless population is known to congregate behind the warehouse near a drainage area, according to Marshall.
The cause of the fire remains under investigation, and Marshall said fire investigators might not be able to access the building to begin their probe until Thursday.
(ABC7 News contributed to this report)