That large smoke plume visible in much of the East Bay this afternoon? It's got nothing to do with any of the refineries in the region.
The Contra Costa Times has the story, and notes some communities in eastern Contra Costa County are experiencing heavy smoke from the blaze:
The California Fire News blog has a little more on the blaze here: Large Fire on Sherman Island .
Sacramento's KCRA says the fire was a prescribed burn: Smoke seen for miles coming from island fire in Delta.