Officials are investigating whether a vessel that was grounded early Saturday morning north of Dillon Beach spilled fuel into the sea.
Local, state and federal officials are working together in response to the incident, witnessed by the Coast Guard at about 1 a.m. Saturday.
The incident happened during the voyage of the 90-foot vessel, American Challenger, which was being towed southward from Puget Sound.
The first report to Coast Guard officials came at 8:45 a.m. Friday, that the tugboat pulling it lost propulsion Friday due to the tow rope entangling the propeller, according to a press release from the unified command leading the investigation.
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The Coast Guard Cutter Hawksbill went to the scene and monitored the situation. Sea conditions and visibility caused the continuation of the towing to be unfeasible, and the tugboat was anchored and later towed to Sausalito.
At about 1 a.m. Saturday, the Coast Guard crew reported the drifting vessel American Challenger became grounded on rocks in a remote area south of Estero de San Antonio.
Officials reported that "An investigation is underway to determine the amount of fuel aboard the American Challenger. Overflights have observed a light sheen from the vessel, but it is unknown if the fuel tanks are compromised."
The unified command includes the Coast Guard, California Department of Fish and Wildlife's Office of Spill Prevention and Response, Marin County Office of Emergency Services and the Greater Farallones National Marine Sanctuary.
An environmental unit is assessing protection strategies for sensitive sites in the area, including Tomales Bay.
As of Saturday afternoon, officials said there had been no confirmed reports of oiled wildlife and that there are no impacts to commercial traffic or scheduled marine events.
If oiled wildlife is seen, the public is asked not to approach the animal and instead call the Oiled Wildlife Care Network at 1-877-823-6926.