Enbridge has stockpiled thousands of pieces of pipe at several storage sites in northern Minnesota, in preparation for the company's proposed new Line 3 oil pipeline.

But pipeline opponents contend Enbridge skirted Minnesota law in its permit applications for the pipe storage yards. Missives from the Minnesota Pollution Control Agency (MPCA) — which granted the permits — buttress that notion.

Enbridge in a statement said the "permits were issued in compliance with applicable regulations at the time."

Enbridge wants to build a new 340-mile pipeline to replace its existing Line 3, one of six Enbridge pipelines running from Canada across Minnesota to Superior, Wis. The new Line 3 would follow the current route to Clearbrook, but then jog south to Park Rapids before heading east.

Environmentalists and Indian tribes oppose the new Line 3 saying it could expose a new range of lakes, rivers and wild rice waters to potential oil spills. Calgary, Alberta-based Enbridge said the new pipeline is a necessary safety enhancement.

The current Line 3, built in the 1960s, is corroding and operates at 51 percent of its capacity due to safety concerns. The new Line 3 would restore the flow of oil to 760,000 barrels per day.

Enbridge has stacks of pipe at several staging areas, including Cloquet, Minn., ready to go if the Public Utilities Commission (PUC) approves the project. The PUC is expected to decide on Line 3 in April.

Enbridge had to get "construction stormwater permits" for the pipe storage yards. In 2015, the MPCA issued the permits, which deal with controls for stormwater runoff.

In May 2016, the MPCA conducted inspections of eight pipe yards and found Enbridge to be compliant with the stormwater permits. But the MPCA found a problem on another front.

Under law and MPCA regulations, permits such as those for Enbridge's pipe yards aren't supposed to be issued before the completion of an environmental review for an entire project. The MPCA wrote to Enbridge in March that the pipe-yard permits were approved "prior to completion of the required environmental review" of Line 3.

In the case of Line 3, a state-conducted environmental impact statement wasn't completed until August. The PUC has not yet approved the EIS.

MPCA stormwater permits are applied for online. Applicants must check a box indicating if an environmental review of their project had been completed. If the box is checked and the application contains all required information, a permit is automatically issued, according to a letter from an MPCA attorney to pipeline opponent Willis Mattison. Enbridge checked the box on its permit applications.

"This has undercut the environmental review process and prejudiced it in favor of Enbridge," said Mattison, who spent nearly three decades with the MPCA, mostly as a regional director, before retiring in 2001.

Mattison, along with environmental activist group Honor the Earth, has been pushing the permit issue with the PCA and other state agencies. The law in question is the Minnesota Environmental Policy Act (MEPA), a decades-old statute that among other things governs permitting.

Enbridge said it obtained the pipe-yard permits prior to a September 2015 Minnesota Court of Appeals ruling "that activated MEPA's applicability to the [Line 3] project." Thus, MEPA did not yet apply when Enbridge applied for the permits, and "statements to the alternative are simply not true," the company said.

Paul Blackburn, an attorney for Honor the Earth, disputed Enbridge's contention, saying MEPA covered the pipe-yard permits regardless of the appellate court decision. MEPA "applies to Line 3 and all permits for that project."

Blackburn criticized the MPCA, too, for having a "gap in its permitting process for major projects."

The MPCA said in a statement that it processes thousands of construction stormwater permits annually through its online system. "It would be impossible to manually double-check on the status of any pending environmental reviews for each individual application," the agency said.

When the MPCA does discover a rule violation, there's a "sliding scale" of potential enforcement actions, the agency said. "MPCA did not assess a penalty against Enbridge because the company complied with all construction stormwater requirements and because there was no harmful environmental impact from construction of the pipe yards."

Mattison took complaints about the stormwater permits to the PUC, the primary regulator for Line 3.

The PUC appeared to reject the claims, citing state pipeline construction rules. The PUC wrote Thursday to Mattison that there's no evidence that Enbridge's pipe yards are on land within the Line 3 route itself, thus no construction on the pipeline itself has begun.

Said Mattison: "They are ignoring what MEPA says and cherry-picking the finer points of a legislative construction rule."

Mike Hughlett • 612-673-7003