Enbridge calls it "the largest project in our history."
State officials say it "presents significant issues."
Opponents have said it could "desecrate our lands, violate our treaty rights or poison our water."
Another oil pipeline fight is heating up.
Enbridge is seeking Minnesota's approval to build a new pipeline to replace its aging Line 3, which would expand capacity and carve a new path for pipelines across the state. Before that can happen, the project is going under the microscope of an environmental review.
Ahead of that study's release, likely next month, here is a look at the basics of the project.
What is it?
The Line 3 replacement is a new pipeline to carry crude oil from Canada to Superior. Specifically, it's a 36-inch pipe that will be able to carry 760,000 barrels of oil from the tar sands of Alberta to the Enbridge terminal in Superior.
That 1,031-mile line will cost about $7.5 billion to build. About 337 miles of pipe will cross through Minnesota.
"Line 3 is a replacement project intended to upgrade and improve the pipeline while restoring capacity to its original volume to meet the demands of refineries in Minnesota and the Midwest," company spokeswoman Shannon Gustafson wrote in an email.
Enbridge wants the last leg of the replacement to follow a new path between Clearbrook, Minn., and Superior instead of following the existing Mainline route shared with several other Enbridge pipelines. That is a major concern of pipeline opponents, along with the fact that the old Line 3 will largely be left in the ground.
Why is it needed?
The original Line 3 was built between 1962 and 1967, runs at half its original capacity and requires increasing attention. Ultimately, that makes it more cost-effective to build an entirely new pipeline.
"Line 3 has experienced external corrosion inherent and common in the pipe coatings used at the time the pipeline was constructed in the early 1960s," Gustafson said. "Enbridge currently forecasts more than 6,000 maintenance activities are required on the line in Minnesota alone over the next 15 years to maintain safe operations."
It will be up to the state to decide if a new line is in the public interest with the aptly named Certificate of Need, which Enbridge applied for in 2014.
In that application, the company wrote: "By replacing Line 3, Enbridge will be able to ensure the continued safe, reliable transportation of crude oil to refineries in Minnesota and beyond, while minimizing potential impacts to the environment and landowners."
Why is it being opposed?
So what happens to the old pipeline?
As with the fight over the Dakota Access Pipeline, tribal groups are stepping up to oppose the Line 3 replacement.
"They've chosen this time to go around the reservations so they don't need to get tribal approval," said Eryn Wise, an organizer with Honor the Earth. "But where they need to go through is (much) of the country's wild rice habitat."
The threat of an oil leak or spill hangs heavy for those whose cultural identity or livelihood is tied to the environment.
"So much of Minnesota's economy is wrapped up in the waters we have, and this has the potential to affect so many of them," Wise said.
Enbridge says in response that "we are committed to keeping the environment safe, clean and protected."
Another group, Minnesotans for Pipeline Cleanup, wants Enbridge to be on the hook financially for the old Line 3 once it is abandoned. Even without oil flowing through the pipe, the group argues, the decaying remains could pose a threat to water, land and property rights.
"I think it's just a scandal that Enbridge isn't going to pull up that old pipeline," said John Munter of Warba, a member of the landowner group. "Iowa has a great law: If a pipeline is abandoned, after five years landowners can request the pipeline be removed at the expense of the owner. We don't have that here."
There is one Minnesota law that addresses pipelines taken out of service, and that applies only to easements for pipes built after 1979.
Enbridge plans to "permanently deactivate in place" the old Line 3 once the new pipeline comes online.
Federal pipeline safety law requires Enbridge to disconnect, clean out and seal the ends of the pipes that remain and file a report detailing where it crosses waterways.
The company also plans to keep monitoring the pipeline - which runs alongside several of its other pipelines anyway - and Enbridge will have parts of the pipe cut out, or segmented, to help prevent the pipes becoming waterways.
"This is the most widely used method for pipeline deactivation and meets all regulatory requirements," Enbridge states.
That doesn't mean it will make everyone happy.
"It should be the landowners' choice if they want the pipe out or not," Munter said. "Mining companies have to remediate their sites, by law, and pipeline owners should really come under the same principle."
He agrees that in some cases digging up the pipe could be more dangerous than leaving it in place, since it sits so close to other active pipelines in some areas. But landowners could be left with a rusting pipe on their property with little recourse if the state approves Enbridge's plan as-is.
"It's really up to the Public Utilities Commission," Munter said. "Enbridge won't pull up the pipe unless they're forced to."
How do other pipelines compare?
Of the six pipelines Enbridge runs through Minnesota, the Line 3 replacement would not quite be the largest. Line 4, which went into service in 2002, can carry nearly 800,000 barrels of oil per day and varies between 36 and 48 inches in diameter.
• Line 1: 18/20 inches, 237,000 barrels per day, in-service 1950.
• Line 2B: 24/26 inches, 442,000 barrels per day, in-service 1957.
• Line 3: 34 inches, 390,000 barrels per day, in-service 1968.
• Line 5: 30 inches, 540,000 barrels per day, in-service 1953.
• Line 13: 20 inches, 180,000 barrels per day, in-service 2010.
The Sandpiper, which was sidelined last fall amid regulatory hurdles and declining production on the Bakken, would have carried up to 375,000 barrels per day in a pipeline ranging 24 to 30 inches.
That pipeline would have run along the same route being proposed for the Line 3 replacement. Pipeline opponents argue that opening that route for Line 3 could set a precedent for other aging lines to be shifted as they need to be replaced.
Who gets final say?
The Minnesota Public Utilities Commission will decide whether to allow the pipeline to be built as planned, deny it outright or allow it to be built with conditions it is allowed to set by state law.
The five commissioners, appointed by the governor for staggered six-year terms, are: Nancy Lange, Dan Lipschultz, Matt Schuerger, John Tuma and Katie Sieben.
Though many interests are already trying to bend their ears as the approval process wears on, "commissioners shall not be swayed by partisan interests, public clamor, or fear of criticism," says the PUC's website.
Regardless, by the time the commission votes on the project, there will have been plenty of clamor.
What comes next?
The state Department of Commerce is expected to release the draft environmental impact statement for the Line 3 replacement May 15, though it already pushed its original April deadline back once. Commerce is conducting the review with the Department of Natural Resources and Minnesota Pollution Control Agency.
Following the release, public comment will be gathered, including at 22 public hearings in the counties the proposed pipeline would cross.
Those comments will be collected and reflected in a finalized environmental impact statement. The Public Utility Commission then gets to determine if the review is adequate.
There will then be more hearings in front of an administrative law judge, who will be tasked with collecting evidence from various stakeholders and intervenors before issuing a finding of fact, conclusions of law and a recommendation for the PUC.
Commissioners will rely upon those documents - the environmental review and the procedural record - to make their decision. It could take months or a year or more to reach that point.
Finally, no matter the decision, there is always the possibility the project ends up in court, pushing back Enbridge's goal of activating the new pipeline in 2019.
Or, if the governor backs down on vetoing legislative efforts that would allow Enbridge to sidestep this review process, construction could start this summer.