UPDATE (9:40 a.m.):
Authorities are investigating whether a mysterious odor is linked to a 40-foot wide oil sheen on San Pablo Bay, north of San Francisco.
The U.S. Coast Guard confirmed the sheen Wednesday.
On Tuesday night, Vallejo residents were told to stay inside after the odor prompted several people to go to a hospital with respiratory issues.
The shelter-in-place order was later lifted but the source of the smell had not been pinned down.
(AP) - Fire officials in the city of Vallejo have issued a shelter in place order due to a strong gas odor.
The Vallejo Fire Department said Tuesday evening it has received more than 500 calls reporting a strong gas smell in the Glen Cove and Beverly Hills Park neighborhoods.
It says the odor is not linked to any natural gas or refinery burn off.
The department says fire Pacific Gas and Electric crews are on the scene trying to determine the source of the odor.
Fire officials say gas monitor readings remain normal.