A fishing boat sank near Marshall last Monday, unleashing a sheen of diesel fuel over the surface of Tomales Bay before the wreck was refloated and removed. The Marian, a 33-foot wooden vessel, had been anchored in the area for several years and was apparently in derelict condition. The incident is under investigation by the United State Coast Guard and the National Oceanic and Atmospheric Administration.

Teams from three separate agencies—the Coast Guard, NOAA and the California Department of Fish and Wildlife’s Office of Spill Prevention and Response—responded the next day. They laid absorbent boom around the vessel to contain the spill on Tuesday evening, and over the following two days, contractors for the Coast Guard refloated the sunken boat with airbags, defueled it and plugged its vents to prevent further leakage. NOAA teams towed the wreckage to Marconi Cove on Thursday afternoon, where it was crushed by an excavator. 

Before it was contained, the fuel spill drifted into a shellfish lease area where the Point Reyes Oyster Company stores submerged bags of oysters. Co-owner Whit Strain said his company immediately hauled away two boatloads of oysters from the area to another lease, though it’s unlikely the slick hurt anything. “We didn’t feel that our oysters were contaminated, but we didn’t want to take a chance, either,” Mr. Strain said. “As oyster growers, we know how to deal with stuff like that. It’s just a shame that it had to happen.”

The Marian, built in 1946, was in poor shape, and many on the eastern shore of the bay had been expecting it to sink. Mr. Strain said he had noticed it was full of holes and assumed that it was totally abandoned. “It’s amazing that it made it this long,” Mr. Strain said. “The owner hasn’t been responding to anyone’s calls for years.”

Patrick Roy Harper, the boat’s owner, was fined $5,000 in 2019 after the Marian broke loose from its mooring and ran aground north of Nick’s Cove, damaging federally protected seagrass. NOAA, which issued that violation, has opened an incident report for last week’s sinking and will be investigating along with the Coast Guard, said Paul Ortiz, a NOAA enforcement attorney. 

Mr. Harper could not be reached for comment. 

Officials removed more than 150 gallons of diesel fuel from onboard the boat, and are not yet sure how much spilled, said Petty Officer Taylor Bacon, a public affairs specialist with the Coast Guard. He stressed that the substance was diesel, not crude bunker fuel, so the environmental impact would be minimal. “Diesel is not a heavy contaminant,” he said. “It’s a lighter substance, it sits on the surface.”

Officer Bacon said the slick would evaporate on its own. “The environment does a really good job of dispersing that type of fuel,” he said.

Yet local environmentalists are concerned about the collective effect of shipwrecks around Tomales and Bodega Bays. Richard James, an Inverness resident known for his work removing plastic pollution from the area, said authorities need to be more proactive in addressing the risk of oil spills. 

“Had this boat been removed two years ago while it still floated, many thousands of dollars would not have been wasted, and Tomales Bay would be in better shape,” he wrote in an email to legislators.

Mr. James said those responsible often avoid accountability because owners are frequently uninsured, leaving taxpayers to foot the bill for recovery efforts. Those efforts are further complicated by the fact that the emergency Oil Spill Liability Trust Fund, which is funded by taxes on oil companies, only pays for part of the work.

Earlier this year, a larger fishing vessel, the American Challenger, wrecked on the rocky shore north of Dillon Beach. Emergency funding for the incident ran out once the oil spill threat was addressed, and the Challenger was left on the rocks. After the incident, Assemblyman Marc Levine introduced a bill that would require all commercial vessels to carry a minimum of $1,000,000 of insurance to cover wreck removal costs. The bill would need to be passed in next year’s legislative session.