A group of U.S. environmentalist and Indigenous voices met with the consul general of Canada in Seattle on Thursday to register their opposition to the expansion of the Trans Mountain pipeline.

The meeting included Dow Constantine, elected leader of King County — which includes Seattle — as well as seven advocacy groups and members of local Indigenous groups.

Afterward, Stephanie Buffam with the environmental group Friends of the San Juans said the meeting was held to drive home their opposition to the project over fears of what a spill could do to the coastal waters shared by B.C. and Washington State.

"Eight million residents who call the Salish Sea home are dependent on a robust, healthy environment that people come here to enjoy," Buffam told CBC's All Points West host Jason D'Souza.

"A catastrophic event, or even a small event disrupts that movement of people visiting the area, as well as disrupts the $30 billion in shipping that depends on uninterrupted clean water."

Buffam says even though the project is within Canada's jurisdiction, its placement means Americans have skin in the game too.

She feels the ocean protection regime is not strong enough and the increased shipping could threaten the salmon and orcas that travel across U.S. and Canadian waters freely.

'False choice between jobs or the environment'

On Tuesday, Canada's consul general in Seattle, Brandon Lee, wrote an op-ed for a U.S. audience defending the pipeline and Canada's commitment to the environment.

"Washingtonians have no greater ally in the protection of our sea, land and air than Canada," he wrote.

"Canadians have never accepted the false choice between jobs or the environment: vibrant, progressive societies need both. I know Washingtonians think the same."

However, a week earlier, Washington Gov. Jay Inslee wrote an editorial of his own, calling the federal government's purchase of the existing Trans Mountain pipeline "a major step backward."

Buffam says she and others in her coalition want to see Canada and the U.S. focus more on a "just transition" to clean energy instead of investing in fossil fuels.

Listen to the full interview:

With files from CBC Radio One's All Points West