Gov. Tim Walz should call for an immediate moratorium on copper-nickel mining in northern Minnesota. Successful leaders change their minds in the face of new information, evidence and evolving ideas. It's called judgment.

We are at a tipping point for a potential mining disaster. This debate has unfortunately become polarized. We shouldn't be put into pro-mining or anti-mining boxes. Fundamentally, this is a quality-of-life and public-health issue. Here's what we know and what we should do.

Attorney General Keith Ellison should conduct a thorough investigation of the Glencore Corp., the Swiss mining conglomerate that acquired a 72% ownership stake in PolyMet. Glencore's bleak environmental mining record includes toxic emissions, land and water contamination, and increased rates of lung cancer of people living near its operations. It has a record of alleged corruption, money laundering and tax evasion. The company is being investigated by the U.S. Department of Justice.

Glencore has been accused of labor violations, including anti-union intimidation, lockouts and workers forced into short-term contracts under the poorest conditions. The United Steelworkers excoriated Glencore for corporate irresponsibility. Glencore has been denounced for human-rights abuses, including the use of child labor, displacing indigenous peoples and bribing government officials worldwide. As former Gov. Arne Carlson said, "Alarm bells should have gone off all over the place. … It's like making an investment in a company and suddenly finding the mob owns it."

A breach at PolyMet's proposed tailings basin near Hoyt Lakes would mean toxic waste would flow into the St. Louis River watershed and directly impact Lake Superior. The decision by the Minnesota Department of Natural Resources granting a permit to PolyMet does not inspire confidence. The DNR said, "If constructed, operated, and maintained properly it will be safe and protective of human health and the environment." That is a lot of "ifs" and a big leap of faith, not to mention that treatment of the tailings would be required for 500 years.

Twin Metals, owned by the Chilean multinational Antofagasta, which also has a dismal environmental record, intends to build a copper-nickel mine 15 miles southeast of Ely. A spill from Twin Metals would directly affect the pristine Boundary Waters Canoe Area Wilderness.

We either roll the dice with these mining companies or help northern Minnesota with viable alternatives. The tourist industry is thriving and will continue to grow as people seek the unique wilderness of Minnesota's lake country, but for more than 100 years, mining has been an integral part of the culture of the Range that provides good-paying jobs. The boom-or-bust economic cycles of mining would be mitigated by new manufacturing investments to diversify the economy.

In 2013, when the Mayo Clinic was hinting that further expansion would occur outside of Minnesota, the state determined there was a compelling interest to make public investments in the Rochester area. The Destination Medical Center (DMC) was created. A public and private investment of $5.6 billion is to be directed to the Rochester area over a 20-year period. These investments are expected to provide dramatic growth with a promise of 35,000 new jobs. PolyMet is promising 350 jobs.

While not an apples-to-apples comparison, a future DMC-like investment could be made on the Iron Range in exchange for permanently abandoning sulfide mining. The Iron Range (business, labor, planners, the Iron Range Resources and Rehabilitation Board, and community leaders) would have to decide what is viable. Private- and public-sector investments might focus on fast-growing industries like solar and wind turbine construction, services that support mining, high-tech industries, fabricated metals, production of machinery and electrical equipment, etc. Cleveland Cliffs recently invested $100 million to mass-produce DR-grade pellets at its Northshore Mining plant in Silver Bay, providing a new market for iron ore processors along with traditional taconite. The Iron Range has the added advantage of shipping finished products around the world from the Port of Duluth.

Public subsidies are controversial, and a DMC-like investment would have to be thoroughly thought through by the state, Iron Range communities and the private sector. An investment to diversify manufacturing on the Range would be far preferable to the costs of environmental damage caused by sulfide mining that would not only affect the Northland, but Minnesota's entire economy.

I lived in Duluth in the early 1970s, when Reserve Mining was dumping 67,000 tons of taconite tailings into Lake Superior every day. I remember lining up at the fire station to fill plastic jugs with filtered water because the tailings were asbestos-like — a known carcinogen. I continue to wonder if the cancer that killed my mother was caused by drinking that water for 25 years.

Former and present elected officials have said that PolyMet is worth the risk. However, a cataclysmic environmental accident is not worth gambling on. Legal battles will continue; but that doesn't mean that Walz, with his moral and political authority, couldn't start a new conversation.

Michael Paymar represented District 64B in St. Paul in the Minnesota House for 18 years and served on the Duluth City Council for eight years.