The thick plume is visible from San Francisco and people from miles away report smelling the smoke.
The fire has been burning uncontrolled in the Delta since just before noon today on Sherman Island near Antioch, in an area that straddles the Solano County-Sacramento County lines in the Delta.
It is uninhabited and full of tule and thatch. There was nobody on the island.
It is unknown how the fire started. At least two-thirds of the area, or roughly a couple square miles, have already burned.
Contra Costa County has issued an advisory for people with asthma and other respiratory problems not to go outdoors.
Joe Perez of Walnut Creek described what he saw this afternoon. "I was at a ball field in Concord before I came here and you could smell the smoke there in Concord. And as we were coming to this restaurant to have dinner, soot and stuff was falling on the car all the way through Pittsburg, and it just seems like it's getting darker and darker out there."
One of the reasons it's apparently so dark is because of the tule which has oil over it. There was some speculation from fishermen that maybe hunters had put tires out there to make it easier to navigate the marshy area during hunting season.
The game plan according to the Suisun Fire District is to let the fire continue to burn, which could last until midnight. It is too unsafe to get firefighters out there to fight the fire. Water in the marshy area is not deep enough to get boats.