A tugboat began sinking in the Tennessee River over the weekend, spilling thousands of gallons of diesel into the water, police in Alabama said. 

Officials don’t know when exactly over the weekend the towing vessel “Michael R” started to sink at a pier in Florence, but it happened at some point between Friday and Sunday, the U.S. Coast Guard said, referring to the incident as a “partially sunken tugboat.”

Diesel fuel began to wash up on the beaches of McFarland Park, police said Sunday. Officers got swimmers out of the water and urged people to avoid swimming and stay off beaches until further notice. The park is a popular area that features fishing piers, boat slips, a beach area and playgrounds, according to Florence’s website.

A containment boom is limiting diesel discharge from a partially sunken tugboat in Florence, Alabama, July 17, 2023.

U.S. Coast Guard photo, courtesy Marine Safety Detachment Nashville

The Alabama Department of Environmental Management and the Coast Guard both responded to the sinking. The Coast Guard will be leading the investigation into the cause of the incident.

The maximum potential for the spill is 2,500 gallons of diesel fuel, a Coast Guard spokesperson said. A hard boom was deployed to contain the bulk of the fuel, and a vacuum truck and a drum skimmer are being used to recover the diesel. 

So far, no negative effects on aquatic organisms have been documented, authorities said. No injuries have been reported. Local officials said the diesel spill also did not impact the City of Florence’s drinking water treatment plants, both of which are upstream from the impacted area. 

The owner of the tugboat contracted a company to begin cleanup operations, according to the Coast Guard. A salvage plan is expected by Tuesday.