Authorities in California are investigating a Chevron refinery spill that dumped about 600 gallons of petroleum and water into the San Francisco Bay.
The sight of it alarmed local residents, such as Richard Katz: "I've been here 30 years in that house right there and no, I've never seen a spill like that before."
Environmental groups are worried about the potential harm to wildlife. David Lewis is the with the group Save the Bay.
“Right next to the Chevron wharf is one of the major haul-out areas for harbor seals. This time of year - there's also migratory birds that are on the surface - of course all year round there are fish and sharks that could be poisoned by this oil.”
In an e-mail to Reuters, Chevron said it first noticed a sheen on the water around 3pm on Tuesday near the wharf at its Richmond refinery.
It said clean-up was underway. The regional air pollution regulator on Twitter said the spill had been contained.