A hose failure during defueling operations aboard the Navy destroyer USS Sampson resulted in a diesel spill at Vigor Shipyards on Harbor Island in Seattle, according to the Washington State Department of Ecology.

The spill occurred at approximately 3:45 p.m. while crews were removing fuel from the vessel. The department initially reported that approximately 2,000 gals. of diesel were discharged into Elliott Bay, while subsequent estimates placed the spill between 2,500 and 5,000 gals.

The exact amount released was still being determined.

The Sampson was surrounded by a containment boom before the fuel transfer began, and the diesel was discharged into the pre-boomed area around the vessel, the department said. The containment measure helped limit the spread of the fuel while response crews began recovery operations.

The Dept. of Ecology responded to the spill and coordinated cleanup efforts with the U.S. Navy, U.S. Coast Guard and response contractors.

“Fuel was being removed from the naval vessel USS Sampson when an estimated 2,000 gallons of diesel was discharged to Elliott Bay,” the department said in its initial response. “The fuel spilled into a pre-boomed area around the vessel. Recovery is ongoing.”

Cleanup and monitoring operations were expected to continue through Tuesday night.

The Arleigh Burke-class guided-missile destroyer was at Vigor's Seattle shipyard when the spill occurred. The cause of the hose failure was not immediately provided.