Bay Area Rapid Transit also shut down three stations near the plant for several hours.
To the south, Oakland police issued a community advisory suggesting that residents of the North Oakland Hills area close all windows and doors and turn off air conditioners.
A fire at the refinery in January 2007 injured two workers and spewed low levels of sulfur dioxide and other toxins into the air. County officials said then that it was not enough to harm the health of nearby residents.
During an evening news conference, Hearne apologized “to the community for the fire and smoke this evening at the Richmond refinery.”
The refinery is the largest producer of base oils on the West Coast, processing up to 240,000 barrels of crude oil a day, according to the company’s website.
The company said Monday it did not know yet whether production would be affected. The 2007 fire shut down the refinery for most of that year’s first earnings quarter.