Update: 2:57 p.m. Thursday
A unified command is inspecting the tanker docked at the Phillips 66 refinery in Rodeo, where operations have been temporarily suspended.
The company that owns the crude oil tanker -- known as the Yamuna Spirit -- says it is cooperating with local agencies through the unified command.
A combination of federal and state agencies, including the U.S. Coast Guard and the California Department of Fish and Wildlife's Office of Spill Prevention and Response, say they are investigating a "broad range of potential sheen sources" that include refineries, facilities and vessels.
According to a press release from the unified command, there has been no visible sheen surrounding the dock or in the northern part of San Pablo Bay since Wednesday afternoon.
State Fish and Wildlife officials say they have found no oiled wildlife in the water. But Shaye Wolf, with the Center for Biological Diversity, says the bay's ecology will experience long-term damage.
"The reality is an oil spill is impossible to truly clean up," Wolf said. "Most of the oil stays in the ecosystem and does long-term damage. So that's a real concern here."
Update: 9:41 a.m. Thursday
A Contra Costa County health official says the Philips 66 refinery in Rodeo was unloading crude oil from a tanker at its marine terminal at the same time hundreds of Vallejo residents began complaining about a petroleum-like odor Tuesday night.
Local regulators say the tanker called the Yamuna Spirit may have leaked.
Dozens of residents have since been hospitalized after the odor made them sick.
State and federal officials have conducted testing on the oil to determine what material was released. Results were expected to be released sometime before noon Thursday, but that has since changed.
Update: 4:05 p.m. Wednesday
The U.S. Coast Guard is now saying it is responding to reports of two oil sheens in San Pablo Bay near the Phillips 66 refinery. Officials have not said how much oil has spilled, and investigators have not determined the source of either spill.
In a statement, the USCG says a helicopter crew spotted a sheen just over a mile long by 40 yards wide during a flyover at 7:40 a.m. today. Investigators from the Coast Guard and the California Office of Spill Prevention and Response are aboard a small boat taking samples to help determine the source.
A Coast Guard flyover near the Phillips 66 Rodeo Refinery Marine Terminal identified the second sheen. Cleanup crews have placed 1,000 feet of boom on the water surrounding the refinery, and several vessels and skimmers are on scene conducting containment and cleanup operations. No oiled wildlife has been observed yet.
Update: 2:49 p.m. Wednesday
The Bay Area Air Quality Management District says in a statement that "initial indications are that a marine vessel may have a leak in its bow."
The U.S. Coast Guard and state officials are investigating an oil spill in San Pablo Bay that may have produced an odor that sickened dozens of Vallejo residents Tuesday night.
It's possible the Phillips 66 refinery in Rodeo could be connected to the incident.
Vallejo city officials issued a shelter-in-place order after hundreds of residents complained of a gaslike odor, which sent dozens to the hospital.
That shelter-in-place order was lifted Wednesday morning.
"We had over 800 calls to our dispatch center of complaints of the smell, questions about what the smell is," Vallejo Fire Department spokesman Kevin Brown said. "Several dozen of them were medical complaints, so we took several dozen patients into local hospitals."
KQED Science Editor Craig Miller, who lives in Vallejo, described the odor as it first began wafting through the area.
"The air up here first starting turning acrid around 7:00 or 7:30 last evening and gradually became more intense. I would describe the smell as some kind of heavy petroleum distill," Miller said. "It's similar to the smell you would get driving by an oil tank farm except much, much more intense, to the point where the city finally issued a shelter-in-place alert around 8:30."
For several hours Wednesday morning there was no ferry service between Vallejo and San Francisco due to the oil sheen, which had coated two ferryboats. Around 8 a.m., ferry service resumed.
Heidi Carle, who lives about a mile from the Carquinez Strait, was one of the residents sickened by the smell.
"All of a sudden the air that was coming through windows was just about toxic," Carle said. "I could feel that I was starting to get very congested in my lungs, which is not normal, and my head just started pounding."
A light oily sheen was discovered shortly after 8 a.m. today at the Phillips 66 Refinery Marine Terminal in Rodeo, company spokesman Paul Adler wrote in an email to KQED.
From the email:
At the time, a tanker was berthed at the marine terminal. Our internal response team immediately responded to the incident and we notified the National Response Center (NRC) and the United States Coast Guard. Operations at the marine terminal have been temporarily shut down and we are working closely with the Coast Guard and other agencies regarding the response.
The email indicates the exact amount of oil released is not known, and the cause of the incident is under investigation.
In addition to the U.S. Coast Guard, the California Office of Spill Prevention and Response and the Bay Area Air Quality Management District are investigating.
Ted Goldberg, Brian Watt and John Sepulvado contributed to this report.