SEATTLE (AP) — The U.S. Coast Guard is responding to a diesel spill off the west coast of Washington state’s San Juan Island after a 49-foot fishing vessel sank with an estimated 2,600 gallons of fuel on board.

A Good Samaritan rescued all five crew members on the Aleutian Isle as the vessel was sinking on Saturday near Sunset Point, the Coast Guard’s 13th District Pacific Northwest district in Seattle and KIRO-TV reported.

The cause of the sinking wasn’t immediately known. The Aleutian Isle reported it was taking on water about 2 p.m. Saturday, the Coast Guard said.

Coast Guard Sector Puget Sound said personnel spotted an oil sheen about 1.5 miles in length about 5 p.m. Saturday, the district said.

Some of the sheen had entered nearby Canadian waters, Petty Officer Michael Clark said Sunday.

The Coast Guard was working with the Canadian Coast Guard Regional Operations Center, the San Juan County Office of Emergency Management, Washington State Department of Ecology and the non-profit Islands’ Oil Spill Association on Sunday to contain and recover the spill, Clark said.

A subcontractor was placing absorbent booms in the water Sunday to recover visible material, while dive crews were evaluating how to remove any hazardous substances from the fishing vessel and how to recover the vessel, which was located in about 100 feet of water, Clark said.

The Washington Department of Fish and Wildlife planned to activate a hotline (1-800-222-4737) for anyone reporting wildlife affected by the spill, Clark said.

The Coast Guard also said it was working with the National Oceanic and Atmospheric Administration, which was tracking the spill’s trajectory, and others to ensure Southern Resident Killer Whales near the San Juan Islands don’t come in contact with the spill.

San Juan Island is about 90 miles north of Seattle and 16 miles east of Victoria, British Columbia

“We are working with government and industry partners to ensure an efficient and effective containment and recovery response,” Coast Guard Lt. Cmdr. Brian Dykens said in a statement. “The local public, the environment and protected marine species are our top priority.”