In his mandate letter to Transport Minister Marc Garneau, published Friday, Prime Minister Justin Trudeau orders a tanker traffic ban that could sound the death knell for Enbridge’s C$6.5-billion Northern Gateway pipeline.

The mandate letter instructs Garneau to “formalize a moratorium on crude oil tanker traffic on British Columbia’s North Coast, working in collaboration with the Minister of Fisheries, Oceans and the Canadian Coast Guard, the Minister of Natural Resources, and the Minister of Environment and Climate Change to develop an approach.”

“Without a means to convey the bitumen to Asian markets, Enbridge’s Northern Gateway proposal is literally dead in the water,” said Grand Chief Stewart Phillip of the Union of B.C. Indian Chiefs.

“This ban ends the dangerous Northern Gateway pipeline,” declared ForestEthics campaigner Karen Mahon. “Without tankers, crude oil has no place to go. And that means no pipelines, no oil trains moving tar sands to the northern B.C. coast.”

Kitimat retiree Dave McRae, a member of Douglas Channel Watch, noted that the ban applies to oil but not liquefied natural gas tankers. Still, “we’re tickled pink. I can hear the champagne bottles popping,” he told the National Observer. “This moratorium could be a lid on the coffin for Northern Gateway, but let’s hope [the mandate letter] nails it down.”

Enbridge maintained the project can still go ahead. “Northern Gateway and the project proponents, including Aboriginal Equity Partners, remain committed to this essential Canadian infrastructure,” said spokesperson Ivan Giesbrecht. “We are confident the Government of Canada will be embarking on the required consultation with First Nations and Metis in the region, given the potential economic impact a crude oil tanker ban would have on those communities and Western Canada as a whole.”

Garneau’s mandate letter was one of 30 released Friday by Trudeau’s office.