Hundreds of religious leaders are joining in opposition to a proposed oil pipeline that would run across northern Minnesota.

The national group of faith leaders say Enbridge Energy's proposed Line 3 project should not get approval because it threatens Minnesota's climate, environment and Anishinaabe people. They plan to deliver a letter next week to the state Public Utilities Commission and Gov. Mark Dayton.

Oil and water: The Line 3 debate

"At its core, this is a moral issue," the letter reads. "Many of us signing this letter come from Christian and other traditions that in recent years have taken formal positions acknowledging the role of our faith institutions in the mistreatment and deep trauma done to Indigenous peoples.

"We have committed ourselves to seeking ways forward for healing and repair. Our signatures here represent an effort to live out that commitment."

Minnesota Interfaith Power & Light and the Minnesota Poor People's Campaign organized the effort. The letter had 515 signatures as of Thursday morning.

Their letter says Enbridge pipelines have a history of spills, and that Enbridge's new Line 3 route would run through wild rice waters sacred to tribes.

Enbridge says it wants to build a new Line 3 because the existing pipeline is corroding and cracking. Enbridge has had to slash the amount of crude oil it carries southeast from Alberta, Canada. A new line would bring that capacity up to original amounts.

Enbridge also says its new pipeline technology is safer and that none of its pipes built in the last decade have spilled.

However, the letter says, "Even if there were no spills (an implausible outcome), this pipeline would be a massive new investment in fossil fuel infrastructure at a time when the threat of climate change requires a new direction.

Enbridge also says it prioritized tribes' concerns when planning Line 3.

"Our proposed route follows extensive study and is the result of significant input from stakeholders across Minnesota," Paul Eberth, Enbridge's Line 3 project director, said in a statement. "It acknowledges the legitimate concerns of Tribal Nations, it best protects the environment and it has the overwhelming support of communities."

The PUC plans to decide Line 3's fate in late June after four days of hearings and deliberations over whether to grant Enbridge a certificate of need to build the line.