A revised environmental study of Enbridge's proposed $2.6 billion pipeline across northern Minnesota has concluded that an oil spill in the Lake Superior watershed would be unlikely to reach the lake itself.

The Minnesota Department of Commerce on Monday posted a revised environmental impact statement (EIS) for the proposed replacement for Enbridge's current Line 3, which is deteriorating and operating at only 51% capacity for safety reasons. The Minnesota Court of Appeals in June ordered the revisions after deeming the original EIS inadequate because it failed to address the potential effects of an oil spill in the Lake Superior watershed.

A public-comment period on the revisions, posted on the website of the Minnesota Environmental Quality Board, will last until Jan. 16.

"The [Commerce Department's] spill modeling confirms that in the unlikely case of a spill, the Line 3 replacement segment does not introduce risk to Lake Superior," Calgary, Alberta-based Enbridge said in a press statement.

The Sierra Club North Star Chapter, an environmental group opposed to new Line 3, said in a statement that the revised EIS is "another inadequate review that fails to recognize that this pipeline would pose an unacceptable risk to Minnesota's clean water."

Environmental groups and some Ojibwe bands said that the new Line 3, which would partly follow a new route, would add to global warming and open a new region of Minnesota waters to degradation from oil spills. Enbridge said the new line — which would restore the pipeline's full flow of oil — is needed for safety reasons.

The EIS for Line 3 was originally deemed "adequate" by the Minnesota Public Utilities Commission (PUC) in March 2018, about three months before the PUC approved the controversial 340-mile oil pipeline.

Pipeline opponents appealed the PUC's approval of the EIS, forcing a redo of small parts of the voluminous study. The Minnesota Court of Appeals' decision also essentially suspended the PUC's June 2018 approval of new Line 3, which would carry Canadian oil to Enbridge's terminal in Superior.

The PUC will not take up the newly revised EIS until after the public comment period is complete.

For the revised EIS, the Commerce Department did spill modeling on a proposed pipeline crossing at Little Otter Creek in Carlton County. That location was chosen because a hypothetical oil spill there would be more likely to enter the St. Louis River, which drains into Lake Superior, than other pipeline crossings, according to the department.

Little Otter Creek flows into Otter Creek before draining into the St. Louis River below the Thomson Dam, an area replete with rapids and dams.

In a "full-bore rupture" at Little Otter Creek, floating oil might reach the Fond du Lac Dam, and after that it would mix into turbulent water (below the dam) before slowing as it resurfaces.

Beyond that, oil would be driven by wind down the St. Louis River. But due to the river's configuration, it is unlikely the spilled crude "would be blown downstream to any great extent," the Commerce Department concluded.

Oil would likely accumulate on the river's shores, but "without reaching the entrance to Lake Superior."

"Now we know that a spill into Little Otter Creek could travel 20 miles in just 24 hours and send over 500,000 gallons of tar sands crude in the direction of Lake Superior," said a statement by Minnesota 350, an environmental group that opposes new Line 3.

Enbridge, however, said that, by design, the state's spill modeling didn't take into account any mitigation and cleanup efforts by the company. "In real life, Enbridge crews would respond immediately and aggressively to actively address the spill and begin cleanup," the company said.

A worst-case oil spill on Line 3 would cost an estimated $1.4 billion to clean up, a little more than the cost of Enbridge's mammoth spill in southwestern Michigan in 2010. The PUC ordered Enbridge to come up with a worst-case scenario last year.

The pipeline rupture in Michigan caused 834,000 gallons of oil to flow into a tributary of the Kalamazoo River, one of the worst onshore U.S. oil spills. Enbridge's last major spill in Minnesota was in 2002, when Line 3 ruptured and released 252,000 gallons.