Public utility commissioners Tuesday directed a fix for the state’s flawed environmental study of Enbridge’s proposed $2.6 billion pipeline, setting the stalled regulatory process back in motion.

The Minnesota Public Utilities Commission (PUC) originally approved the environmental-impact statement (EIS) for the project — a replacement for the deteriorating Line 3 — in March 2018.

But in June, the Minnesota Court of Appeals, acting on a petition from pipeline opponents, concluded that the EIS was “inadequate” because it failed to address the potential effects of an oil spill into the Lake Superior watershed.

The PUC voted 5-0 on a directive to give the Minnesota Department of Commerce 60 days to redo the small of part of the EIS dealing with the issue cited by the appeals court. The department conducted the EIS, which is mandatory for the 330-mile pipeline across northern Minnesota.

Fixing the EIS “is a fairly straightforward issue,” Louise Miltich, the Commerce’s Department’s environmental-review manager, told the PUC.

Still, it could be several months before the EIS is formally re-approved by the PUC, given required public comment and administrative appeal periods. Paul Blackburn, an attorney for the indigenous environmental group Honor the Earth, said he thinks February will be the earliest that the EIS would receive final approval.

Enbridge, in a statement, said that based on experience with the PUC, it expects a final EIS adequacy approval in about five months.

But the PUC process will include more than the EIS review.

The appellate court decision effectively suspended the PUC’s June 2018 approval of a route permit and “certificate of need” for Line 3 — Enbridge’s two most important permits. So, the PUC will again need to vote on those permits. And it is likely that pipeline opponents like Honor the Earth once again will appeal the Line 3 certificate of need and route permits.

The full PUC permitting process may not be done until May, Blackburn said.

Calgary, Alberta-based Enbridge said building a new Line 3 is an essential safety project. The existing Line 3 — one of six pipelines that Enbridge runs across northern Minnesota — is corroding and operating at only 51% capacity due to safety concerns. A new Line 3 would restore Enbridge’s full oil flow.

Environmental groups and some Ojibwe bands have been fighting the new Line 3 for years, saying it will add to global warming and open a new region of Minnesota’s waters to possible degradation from oil spills. New Line 3 would divert from Enbridge’s current corridor of pipelines near Clearbrook and run on a new route.

After the PUC approved Line 3 in June 2018, Enbridge figured it would have the rest of its permits in line to start building Line 3 this spring and shipping oil by November. The project opening date has since been pushed back to the second half of 2020.

Enbridge must still get several other state and federal permits — notably from the Minnesota Pollution Control Agency, the Department of Natural Resources and the U.S. Army Corps of Engineers. Those permits are more technical than the PUC’s permits, and include several water-quality issues.

Last week, the MPCA formally denied Enbridge’s request for a “401” water-quality permit, though the action was expected. The MPCA can’t approve that permit before the EIS is remedied. Yet under federal law, the MPCA had to take action on Enbridge’s application before Oct. 30.

Enbridge said it will reapply for the water permit, and that the MPCA’s denial shouldn’t affect Line 3’s timeline.