ST. PAUL — An oil spill along the proposed Enbridge Line 3 replacement line would have minimal impacts on Spirit Lake and the Lake Superior watershed, according to an assessment released Monday, Dec. 9.

The Minnesota Department of Commerce released the addition to the proposed $2.9 billion pipeline project's environmental impact statement after a Minnesota appellate court said the company's proposal was inadequate without it.

And as part of a court-required assessment of the damage that could be done to the Lake Superior watershed, the model shows that "even in an unmitigated release, it is unlikely that any measurable amount of oil would reach Lake Superior."

Enbridge officials on Monday said the analysis shows that the project merits a green light from state regulators, but they weren't sure what a timeline would look like for breaking ground on the project. Additional permits are needed in Minnesota to start construction on the 350-mile section across northern Minnesota.

Sections of the pipeline, which is slated to extend from Alberta, Canada, to Superior, Wis., have already been permitted or completed in Canada and Wisconsin. And permit applications in North Dakota have been submitted and are under review.

"We have research and modeling that confirms there is no introduction of risk to Lake Superior when crude oil release based on the modeling," Barry Simonson, Enbridge's director of Line 3 replacement execution, said deeming the outcome "very positive in nature."

The assessment commissioned by Enbridge and reviewed by the Department of Commerce-contracted experts shows a worst-case scenario of what could happen if the line had an accidental full-bore leak near the Lake Superior watershed. And 24 hours after a complete break occurred, little oil would make it from the Little Otter Creek to the St. Louis River or onward to Lake Superior, the model shows.

But the potential damage should be enough to put the brakes on the project, advocates from environmental groups opposing the pipeline project said. Spokespeople from the Sierra Club and MN350 said the projections noting the spill could send hundreds of thousands of gallons of oil 20 miles in 24 hours should raise red flags for Minnesotans.

"Even on this court-ordered third try, the Public Utilities Commission has produced yet another inadequate review that fails to recognize that this pipeline would pose an unacceptable risk to Minnesota's clean water and should never be built," Sierra Club North Star Chapter Director Margaret Levin said in a statement. "Now it's more important than ever that Governor Walz and the Pollution Control Agency do everything in their power to stop this dirty tar sands pipeline once and for all."

Oil spill experts planned for different kinds of oil and for three seasonal variations as part of their assessments of potential environmental impact. The leading edge of oil in a potential spill could reach the Fond du Lac Dam and from there would likely mix into turbulent water.

Fish could be exposed to toxic levels of oil in a spill situation, the report says. And even with strong wind on the St. Louis River, it's unlikely the oil would blow downstream toward the entrance of Lake Superior.

Enbridge officials said the company makes significant investments into maintaining pipelines and preparing for any accidental releases. Minnesotans can comment on the review before January 16.

Enbridge officials signed off on labor agreements for the pipeline construction project last week. And they said they hope to start work on the project next year. They estimated it could take 7-9 months to complete and officials estimate the project will generate 2,000 new jobs for trades workers.

Enbridge's proposed pipeline would carry 760,000 barrels of oil (31,920,000 gallons) per day from Alberta to the Enbridge terminal in Superior. The pipeline would replace Enbridge's existing 50-year-old Line 3, but follow a new route through much of Minnesota.

This story has been updated to correct the time it would take to complete the project to 7-9 months.