"Because of the wind, we are worried about fire extension," fire Capt. Robert Marshall said earlier.
The fire was reported around 1 p.m. at the former Concord Naval Weapons Station in Bay Point near the General Chemical Corp. plant in the area of Nichols Road and Port Chicago Highway, according to Marshall.
The fire captain said the federal chemical plant was not threatened by the fire, although employees there were briefly ordered to shelter in place.
Part of Port Chicago Highway was shut down as crews battled the fire.
No evacuations were ordered and no structures are threatened.
KGO contributed to this report.