Canada's westernmost British Columbia province on Friday rejected a proposed pipeline to move crude from the oil sands of Alberta province to the Pacific coast, citing environmental concerns.
In a written submission to a federal review panel, British Columbia said it could not support Enbridge Inc's Northern Gateway pipeline.
Key questions about the pipeline route and how Enbridge would respond to spills remained unanswered, the document read.
"Our government does not believe that a certificate should be granted before these important questions are answered," provincial Environment Minister Terry Lake said in a statement.
He noted, however, that the government's position on the Northern Gateway project is not a rejection of all heavy-oil projects, saying each "will be judged on their merits."
The Northern Gateway pipeline would move oil from the tar sands of neighboring Alberta to a new marine terminal in Kitimat, British Columbia, for shipping to Asia.
Up to 220 supertankers a year would dock at Kitimat to fill up on crude, one report estimated.
Aboriginals and environmentalists however oppose the terminal, saying tanker traffic poses risks to a pristine coastline that includes salmon-bearing rivers and the habitat of a rare white bear.
The plan gained momentum after the United States initially rejected TransCanada's Keystone XL pipeline connecting the Alberta tar sands to Texas refineries.
The US State Department is expected to make a final recommendation on the Keystone project to President Barack Obama in the coming months.
A panel reviewing the Northern Gateway project will wrap up hearings in June, and a decision on the project is expected at the end of the year.
Explore further: US House sends message on Keystone pipeline