New Brunswick environmentalists are hoping that Ottawa will step in to review the impact of a second Irving Oil refinery for Saint John.

A multibillion-dollar construction project, the refinery could be a huge boost for New Brunswick exports, and would be a big step towards fulfilling a Liberal election promise to make Saint John an energy hub.

"This is a wonderful, wonderful opportunity, not only for greater Saint John but for all of New Brunswick," energy minister Jack Keir said Thursday when it was announced the company was registering the project for an environmental impact assessment.

David Coon, policy director for the Conservation Council of New Brunswick, said provincial environmental reviews are "toothless" and questions how tough the Liberal government will be on a project that fits its agenda so well.

"The provincial environmental impact process is subject to political pressure," Coon said. "There's no question about it. We've seen it in the past and it could happen in the future."

Coon said it would serve everyone well if the assessment was led under federal rules, with an independent review panel that would report publicly.

"If the government doesn't like the report, then they can take the decision to do something different and pay the political consequences," Coon said. "That's the way it should work."

The doubling of oil tanker traffic implied by a second refinery may trigger a federal environment review, Coon said, because of the increased risk of oil spills and collisions with the endangered North Atlantic right whale.