Refineries May be a Major Source of Mercury Pollution

During a public hearing this morning, the San Francisco Bay Regional Water Quality Control Board will be taking the unprecedented step of requiring local oil refineries to calculate the amount of mercury contained in crude oil. This significant step will go a long way towards protecting the public and making San Francisco Bay’s fish safer to eat. New information suggests that the Bay Area’s five local refineries could be depositing as much as 1,700 kg (more than 3700 pounds) of mercury into the Bay Area’s environment every year. Mercury is a known neurological and developmental toxin that is especially harmful to fetuses and young children and is responsible for public warnings to limit eating fish from the Bay.

The Water Board recently adopted a plan to cleanup mercury in the Bay, but Baykeeper determined that the plan may have underestimated how much mercury is being emitted by the five local Bay Area oil refineries: Chevron, Conoco Phillips, Shell, Tesoro and Valero. The Board’s initial estimates showed that crude oil processed annually by the refineries contained 380 kg of mercury (equivalent to the releases entering the Bay from the mercury-laden Sacramento River, long-polluted by old gold mines.). Today’s new findings suggest that oil refineries could be releasing as much as 1,700 kg of mercury into the environment – potentially the single biggest source of mercury in the entire estuary. After researching the amount of mercury in crude oil nationwide, Baykeeper began asking the Regional Board two years ago to require the refineries to show whether the toxic chemical was being deposited in the Bay.

“Trying to clean up mercury in the Bay without knowing how much mercury is in crude oil is like trying to balance your checkbook without knowing what your opening balance is,” said Baykeeper Program Director Sejal Choksi. “The Board is taking a bold step today by requiring the oil industry to produce the critical data.”

In 2005 the Water Board required the Bay Area refineries to determine how much mercury is in their air emissions because this mercury could then be deposited into the Bay. Baykeeper and other environmentalists argued that the more logical study was to calculate how much mercury is entering the refineries and then compare this number to the amounts that leave the refineries via various pathways such as in solid waste, wastewater, and air emissions. The refineries fought the larger study. Now, they are not only two years behind schedule in complying with the 2005 air emissions study, but the Water Board believes that the Bay Area petroleum refineries also failed to submit crude oil samples for analysis as part of a national API-EPA study of mercury in crude oil.

One report cited by the Water Board estimates that “crude oil from California can range from 80-30,000 ppb mercury. The crude oil known as Cymric was the highest in mercury content, and this oil comes from the San Joaquin Valley” – a crude oil deposit which may be the source of at least sixty percent of the oil used by Bay Area oil refineries. Draft Section 13267 Information Letter from Bruce Wolfe, Regional Water Board Executive Officer, to Bay Area refineries, page 4 (April 12, 2007). Available on Regional Board website:


Baykeeper is a non-profit environmental organization that watchdogs the San Francisco Bay watershed, fighting to stop the theft of our waterways by polluters.