Dozens of orcas, hundreds of thousands of seabirds and millions of salmon were wiped out when the Exxon Valdez oil tanker spilled 40 million litres of crude oil into Alaskan waters.

Twenty-one years later, a coalition of British Columbia First Nations says such a disaster can never be allowed to happen again, and declared it will do whatever it takes to stop a proposed pipeline from the Alberta tar sands to the B.C. coast.

More than 150 First Nations, businesses, environmental organizations and prominent Canadians have signed on to the campaign to stop the pipeline proposed by Calgary-based Enbridge Inc. (TSX:ENB)

They say the risk of an oil spill is just too great.

"We all believe the Enbridge Gateway pipeline project is a threat to the very existence of our culture and our way of life," Art Sterritt, executive director of the Coastal First Nations, told reporters Tuesday.

"There are some who believe the Enbridge project is a done deal. It isn't. It is over."

The Northern Gateway Project would see two 1,170-kilometre pipelines stretching from the tar sands near Edmonton to the northern B.C. coast town of Kitimat.

Crude would flow, crossing more than 1,000 streams and rivers, mountain ranges, avalanche-prone terrain and rainforest ecosystems before being loaded onto upwards of 150 tankers annually for export.

The majority of the landscape to be covered is traditional B.C. First Nations land.

"It would be both unwise and irresponsible for Enbridge to ignore us or our constitutionally protected rights and title in British Columbia," Sterritt said.

The Coastal First Nations, who are heading the declaration, are an alliance of communities on B.C.'s north and central coast, including the islands of Haida Gwaii.

Enbridge declined an interview request, citing the fact that it's in the final stages of a regulatory application with the National Energy Board.

But the company has touted the benefits of the project, saying more than 4,000 construction jobs and thousands more indirect jobs would be created, while generating hundreds of millions in tax revenue for both provinces.

The company has said ships have safely carried petrochemicals out of the Kitimat port for 25 years, and they will, in fact, make safety improvements.

In an email, the company said it must still undergo a "comprehensive and rigorous regulatory review process to ensure the project is in the interest of the Canadian public."

But Sterritt said after five years of scientific research and community consultations, the groups that have signed onto the campaign believe "no good" can come from the project.

It could jeopardize the land, water, people and wildlife for generations to come, say those opposed.

"We don't ... make this declaration blindly or lightly, we make it from an informed position," said Gerald Amos, a director of Coastal First Nations.

He said a blockade on the water is possible if the project goes ahead.

Along with 28 B.C. First Nations, the Union of B.C. Indian Chiefs and some aboriginal groups from Alberta, environmental groups including the David Suzuki Foundation and the Pembina Institute also signed on to the campaign.

Author Margaret Atwood, Vancouver Canuck Willie Mitchell and 10 Canadian Olympians, including Kristina Groves, are also on board.

Environmentalist Vicky Husband said she believes two additional pipelines would allow an increase in production in the Alberta tar sands of up to 30 per cent.

"If we actually believe in taking steps to deal with climate change, the tar sands needs to be phased out," she said. "Otherwise, Canada will be a major source of greenhouse gas emissions, ongoing."

Premier Gordon Campbell said the project will not proceed if it's deemed too dangerous for the environment.

He said the government wants to build an economic future for B.C. First Nations, "in a way that meets all of our environmental standards."

The New Democrats called on the government to drop the project, but B.C. Energy Minister Blair Lekstrom said B.C. residents want more money for health care, social programs and roads.

"All of that comes from our resource industry -- and we have to find that balance," he said.