Diesel and Engine Oil Removed from Sunken Tug in California

Petroleum product and hazardous material have been removed from a 1940s era military tugboat that sunk in California, the U.S. Coast Guard said.

A Unified Command and its contractors completed lightering efforts from the tug Mazapeta, Wednesday.

The Mazapeta sunk September 4, 2023, in Little Potato Slough within the San Joaquin Delta, northwest of Stockton, with approximately 1,600 gallons of diesel and engine oil reported to be onboard at the time of the incident.

Quantification of recovered product is ongoing, but an estimated 593 gallons of petroleum product and nearly 26,000 gallons of oily water mixture were recovered to date.

The lead contractor, Parker Diving and Salvage, raised the Mazapeta using a crane barge and dewatering pumps Saturday night into Sunday morning. Crews were able to seal, raise, dewater, and remove petroleum products from the vessel. Batteries and other household hazardous items were also removed.

The Unified Command consisted of representatives from U.S. Coast Guard Sector San Francisco, California Department of Fish and Wildlife’s Office of Spill Prevention and Response, and San Joaquin County Sheriff’s Office and the City of Stockton.

With petroleum removal operations related to the vessel complete, the City of Stockton took control of the Mazapeta and is working with salvage contractors to remove it from the waterway, Thursday, pending appropriate weather and safety conditions. A dead ship tow plan was approved by the Coast Guard to move the Mazapeta from its current location to Vallejo for final disposal.