CONCORD (CBS SF) –A four-alarm fire burning at a Concord warehouse Wednesday morning sent smoke and strong odors of burning plastic across the East Bay.

The fire was reported at a warehouse in the 2300 block of Stanwell Drive near the Buchanan Field Airport around 12:30 a.m., according to Contra Costa County Fire Protection Capt. Robert Marshall.

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A haze of smoke and the smell of burning plastic have been reported throughout central Contra Costa County and as far away as Oakland Wednesday morning, he said.

At one point, 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. That advisory was lifted around 11:30 a.m., according to the department.

Fire officials advised a nearby dialysis clinic to close for the day.

The fire was declared under control at about 2:45 a.m. However, it took firefighters until 11 a.m. or so to put out a stubborn corner of the warehouse that was still burning, Marshall said.

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.

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Marshall said the fire burned “a lot of plastics, a lot of wire.”

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.

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