Some of the cancer-causing gunk that spilled from the Cosco Busan’s fuel tank 12 days ago has dissolved into the Bay; some has attached to flotsam and sunk; and some has lined the Bay’s floor, where it’s expected to kill and contaminate fish, crabs and the microscopic life that feed the marine ecosystem, according to scientists, fishermen and environmental groups.
Nearly two-thirds of the 58,000 gallons of bunker fuel that spilled into the Bay after the 900-foot container ship hit the Bay Bridge is unaccounted for, but officials say they haven’t surveyed the Bay or ocean floor to find out how much settled there. Bunker fuel is a cheap and heavy fuel used in ships.
“Some of the material in the bunker fuel will dissolve into the water column and some of it will sink,” said Jen Kovecses, an aquatic ecologist at the nonprofit San Francisco Bay Keeper. “It’s not easy to remove.”
Dissolved fuel and fuel additives are absorbed through fish gills, according to Kovecses, and accumulate in mussels, polychaete worms and other water-filtering critters that are eaten by bigger creatures.
Benzene and naphthalene, found in bunker fuel, cause cancer, according to the U.S. Environmental Protection Agency.
Gooey bunker fuel, which is left behind after higher-grade fuels are distilled from crude oil, is blended with other fuels and oils to make it runny enough for ship engines. Preliminary tests suggest the Cosco Busan’s fuel had been blended with diesel, San Francisco Bay Keeper Program Director Sejal Choksi said. Diesel contains benzene and similar cancer-causing toxins, according to the U.S. Agency for Toxic Substances and Disease Registry.
Toxins could linger under the surface of the Bay for decades, Save The Bay Executive Director David Lewis warned.
A U.S. Coast Guard statement issued Sunday said that tiny balls of fuel and sand can resurface hours or days after they sink, but the properties of bunker fuel mean all of it stayed afloat or washed ashore.
But fishermen tell a different story.
“I went in very shallow at Angel Island,” commercial fisherman Ernie Koepf said, “and the boat bounced on the rocks on the bottom and kicked up an oil slick.”
Koepf, who advises the California Department of Fish and Game on Pacific herring, asked the department to survey the Bay floor after it canceled an annual underwater vegetation survey.
“If they don’t want to dive because they’ll get oily,” Koepf said, “then we want to be involved in some other method of sampling the hard substrate and the vegetation.”
The water beneath the site of the Cosco Busan crash is used by herring and other baitfish.
“We have now really done something quite awful,” Bay Institute scientist Tina Swanson said, “to what was one of the only healthy parts of the Bay.”