An article published in Sunday's Duluth News Tribune reported that several environmental groups, joined by attorneys general in Minnesota and Wisconsin have filed documents in federal district court opposing the Northshore Mining Co.'s motion to lower the standard for asbestos-like fibers in the air near the company's Silver Bay taconite plant. The court-ordered standard, set in 1974, requires Northshore, formerly known as the Reserve Mining Co., to keep airborne fibers near the plant along Lake Superior, at or below the average level of fibers in St. Paul air. The St. Paul comparison was developed because no human health standard had been set determining how many taconite dust fibers are safe to breathe.

Last year the Minnesota Pollution Control Agency and state courts refused to drop the fiber comparison requirement, prompting Northshore to seek federal court intervention. In support of its position, Northshore claims that the St. Paul comparison is outdated and that the fibers pose no human health risk because the taconite it mines and processes doesn't contain any asbestos. It further contends that dropping the standard won't result in increased airborne fibers but would end an unfair comparison to constantly fluctuating St. Paul fiber levels. Those in favor of keeping the standard argue that Northshore's motion is merely a means to combat efforts to reduce Northshore's "excessive asbestos fiber emissions", citing recent reports from the Minnesota Department of Health showing unusually high levels of mesothelioma lung cancer in Minnesota's Iron Range region. Although scientific data has thus far been inconclusive, some researchers, activists and state officials claim that the amphibole mineral fibers found in taconite dust is close enough to asbestos to cause concern. (See University of Minn. to Study Link Between Taconite Mining and Mesothelioma, posted 8/10/07). A hearing on the matter is scheduled to take place in federal district court in St. Paul on Thursday.