Kirby Offshore Marine’s tug Nathan E. Stewart and barge DBL 55 ran aground early Thursday morning in the Seaforth Channel near Bella Bella, British Columbia, and the stricken tug is leaking diesel into the water.

The Vancouver Sun reported that the articulated tug-barge made up of the 3,400-hp, 95’3”x32’x13’7” Nathan E. Stewart and 287’5”DBL 55 barge ran aground on the Edge Reef at the entrance to the channel while en route back to Vancouver, British Columbia, from Alaska. The double-hulled tank barge was empty at the time, but the tug carried approximately 200,000 gals. of diesel fuel, according to a statement from Kirby.

Matters were complicated when the tug sank later Thursday morning.

Kirby incident commander Jim Guidry told Canada’s CBC News late Thursday that resources to meet "a worst possible discharge" had been activated.

The Heiltsuk Tribal Council, governing body of the Heiltsuk Nation, said they were notified of the incident by Canadian environmental officials and sent three boats to aid the initial response to the spill, which the tribe called "far below acceptable" in a statement posted to Facebook.

Kirby enlisted the services of Western Canada Marine Response Corporation (WCMRC) and the response company dispatched a mobile skimming vessel, two boom skiffs, a workboat and tug and barge with three response trailers to the scene from Prince Rupert, B.C. WCMRC said in a statement that local response contractors laid a boom around the tug while those vessels were en route.

According the Vancouver Sun, Kirby also called in Resolve Marine Group.

“Kirby Offshore Marine, owners and managers of the Nathan E. Stewart regret that this incident has occurred and are working to respond and mitigate the impact of this incident,” Kirby’s Guidry wrote in a statement released to media.

The Heiltsuk Nation manage a traditional fishery in the area, and said that the spill threatens dozens of species in an ecologically sensitive region, including manila clams.

"It's a significant part of our local winter economy. That clam fishery was due to open in about three weeks," Marilyn Slett, chief councillor for the Heiltsuk Tribal Council, told the CBC.

“Our Gitga’at neighbours to the north are still unable to harvest clams and other seafoods ten years after the sinking of the Queen of the North. This spill area is in one of our primary breadbaskets, and we know that diesel is extremely difficult to recover,” Slett said.

U.S. vessels that are under 10,000 gross tons, such as the Nathan E. Stewart, are often allowed to operate without a local pilot on the West Coast of Canada, if the crew meets a minimum standard of experience and licensing, Kevin Obermeyer, CEO for the Pacific Pilotage Authority, told the CBC. Kirby had such an exemption, but Obermeyer said it had been revoked pending the outcome of an investigation into the spill.

Seven crewmembers aboard the tug were evacuated safely.