Yesterday afternoon, a tugboat sank off Treasure Island, spilling an estimated 35 gallons or oil and diesel fuel into the Bay, creating a sheen a "400-foot debris field" sheen of oil surrounding parts of Treasure Island and the Berkeley Marina. "The Coast Guard contracted a private company to clean up the sheen," according to reports, which managed to contain the fuel before day's send. Also, allegedly, no wildlife was harmed or contaminated during the spill. So, that's good. The boat, christened and used by the U.S. Navy for 33 years before retiring in 1974, was docked pretty low in the water before sinking.