Now is the time for everyone who treasures the Boundary Waters Canoe Area Wilderness and its health-promoting pristine water, air, wildlife, fish, and solitude to speak up.

On Dec. 20, the Bureau of Land Management released an environmental assessment covering two hard-rock mineral leases held by Twin Metals Minnesota (“Feds propose renewing Twin Metals mineral leases,” Dec. 21). The assessment can be found at go.usa.gov/xPtDd. The public comment period runs through Tuesday.

Twin Metals is owned by Chilean mining giant Antofagasta, a company that has been fined millions for polluting Chilean waters and land.

The leases, comprising 4,865 acres, are at the edge of and upstream from the Boundary Waters along the South Kawishiwi River in the Rainy River watershed. The leases could lead to Twin Metals mining copper, nickel, and associated metals found there, an activity known as sulfide-ore copper-nickel mining.

During mining, if air and water contact the ore, toxic sulfuric acid can result. This acid could then leach toxic heavy metals that are bound to the ore. Sulfuric acid and heavy metals released would comprise acid mine drainage, which would pollute surface water and groundwater.

The World Health Organization has stated that this type of mining releases six of the top 10 toxins of greatest concern to human health: mercury, lead, arsenic, cadmium, asbestos, and particulate air pollution. These toxins are known to cause cancer, lung disease, heart disease, and neurodevelopmental disease.

The Environmental Protection Agency has declared hard-rock mining to be the most toxic industry in the U.S. Any toxic mining drainage from mines on these leased lands would flow directly into the Boundary Waters.

These leases expired in 2014 and were lawfully terminated in 2016. Since then, Twin Metals has been working to get the administration of President Donald Trump to overturn this decision. In 2018, the Trump administration reinstated the expired leases and is now in the process of fully renewing them. (The legal validity of the administration's reinstatement of expired leases remains under question and is currently being challenged in federal court.)

In the process, the administration has ignored dozens of scientific and economic studies, as well as findings by the U.S. Forest Service, that show sulfide-ore copper-nickel mining poses grave threats to the Boundary Waters and other large sections of the Superior National Forest. In September, a study of the impacts of sulfide-ore copper mining, expected to show how dangerous this type of mining is so close to the Boundary Waters, was canceled.

The Bureau of Land Management’s environmental assessment last month was a brief, cursory review that didn’t address the risks of renewing the leases. Because of the significant environmental, ecological, and health threats from sulfide-ore copper-nickel mining in the watershed of the BWCAW, we need to let the bureau know the current environmental assessment is grossly inadequate.

The National Environmental Policy Act requires a full, comprehensive environmental impact statement be completed for “major federal proposals significantly affecting the quality of the human environment.” An environmental impact statement is a detailed, comprehensive study, based on rigorous science with input from all of the affected constituencies.

We have been studying the human health effects of sulfide-ore copper-nickel mining for five years. A full, comprehensive review is absolutely necessary so policymakers and the public are fully informed about what sulfide-ore copper mining next to the Boundary Waters could mean for our health and the health of our communities.

Please send your comments by Tuesday to the MN Hardrock Lease Renewal EA Project Manager, Northeastern States District Office, 626 E. Wisconsin Ave., Ste. 200, Milwaukee, WI 53202.

Drs. Deb Alert, Steve Bauer, Emily Onello, Jen Pearson, Peg Saracino, and Steve Sutherland are of Duluth. Drs. John Ipsen and Kris Wegerson are of Ashland. They all are physicians who have studied the human health effects of sulfide-ore copper-nickel mining.