The origins of public concern with taconite and human health: Reserve Mining and the asbestos case

Our plain-English summary of The origins of public concern with taconite and human health: Reserve Mining and the asbestos case, by M.E. Berndt, W.C. Brice (Regulatory Toxicology and Pharmacology, 2008).

The study

• Authors: M.E. Berndt, W.C. Brice
• Journal: Regulatory Toxicology and Pharmacology
• Published: 2008;52(1 Suppl):S31-9
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Asbestos first became an issue to Minnesota's iron industry when it was revealed that mineral fibers similar to those in Reserve Mining's tailings were being found in drinking water for several communities that used Lake Superior as their primary water source. This discovery turned what had largely been an environmental court battle into a case concerning public health. The courts listened to much conflicting and uncertain scientific testimony on the size and distribution of the mineral fibers and on the potential health effects imposed by them. In April 1974, the plant was ordered to shut down by a federal judge but the company quickly appealed the decision. The appeals court granted a stay and ultimately ruled that the plant's closure could not be justified based on the unknown health effects of the mineral fibers since the consequences of such an action would have immediate and severe social and economic impacts. The plant was allowed to continue operation, but ordered to abate emissions to air around the plant and to switch to a land-based tailings disposal system. Much of the scientific uncertainty and public concern over mineral fibers in Minnesota's taconite industry remain today.

In plain English

This article is a historical account of a court case, not a health study. The authors described how Reserve Mining Company discharged taconite tailings into Lake Superior from its Silver Bay, Minnesota plant, with production beginning in 1955. A federal pollution lawsuit became a public health case after the public was told in June 1973 that asbestos-like fibers had been found in Silver Bay's air and in the drinking water of Duluth and other lakeshore communities. The fibers were linked to the amphibole cummingtonite–grunerite. Drawing on court records, the authors reported that the district court found these fibers indistinguishable from amosite and ordered the plant shut on April 20, 1974. The appeals court stayed that order. It found a "reasonable medical concern" but, citing a court-ordered tissue study that found deceased Duluth residents virtually free of fibers, concluded there was no imminent hazard. Government witnesses had testified that 98% to 99.3% of amphibole fibers in Duluth's water were under 5 micrometres long. Lake discharges ended in 1980. The authors concluded that no firm conclusions could be made about the health effects of ingested tailings.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Historical and legal review of the Reserve Mining court cases, based on court records and published summaries; no new health data were collected
• Who was studied: No human subjects were studied. The article covers Reserve Mining Company's taconite operations (Peter Mitchell Pit and the E.W. Davis Works at Silver Bay, Minnesota), which discharged tailings into Lake Superior. It also covers the lakeshore communities whose air or water contained mineral fibers, from the late 1940s permits through the 1970s trial and later events.
• Exposure: Mineral fibers of the amphibole cummingtonite–grunerite in Reserve Mining's taconite ore and tailings. They were found in Lake Superior drinking water and in air near the Silver Bay plant. Court testimony put the mineral at an average of about 26%, and up to 60%, of ore in parts of the Peter Mitchell Pit deposit.
• Main results:
  • On April 20, 1974, Federal District Court Judge Miles Lord ordered the Silver Bay facility closed, citing a substantial danger to human health from tailings in the water. Reserve obtained a stay on April 22, 1974.
  • After testimony from both sides, the district court found that amosite and cummingtonite–grunerite were in most instances indistinguishable.
  • Government witnesses at the trial presented evidence that 98% to 99.3% of amphibole fibers in Duluth's water supply were under 5 micrometres long, with an average length of about 0.8 micrometres.
  • A tissue study ordered by the district court, of recently deceased Duluth residents who had drunk Duluth water for 15 years, found them virtually free of fibers. The district court said fibers may have been overlooked. The appeals court relied more on the negative result and concluded no emergency or imminent hazard existed.
  • No evidence of an increase in gastrointestinal cancer rates was found for Duluth residents for 1950–1969, or in another study for 1969–1972. Both courts agreed such studies were premature because of the long latency period of asbestos-related diseases.
  • The appeals court found that the fibers in air and water gave rise to a reasonable medical concern for public health. It overturned the immediate shutdown, gave Reserve a reasonable time to move to land-based disposal, and required air fiber counts at Silver Bay to be reduced.
  • The Mile Post 7 land disposal facility was completed in March 1980 at a cost of $375 million, and lake discharges ended in April 1980. In an April 1982 settlement, the company agreed to pay $2 million for water filtration systems without admitting wrongdoing or harm to public health.
• The authors' conclusion: The authors concluded that, despite expert testimony at trial, no firm conclusions could be made about the health effects of ingested tailings. They asked whether newer science, and the time now passed for long-latency cancers, could resolve questions about fiber type, fiber length and safe exposure levels. They also asked whether an epidemiological study of exposed persons is needed.

Topics

Medical terms in this study, explained in our Lexicon: Taconite, Mineral Fiber, Tailings, Discovery, Appeal.

Related studies

• Risk assessment due to environmental exposures to fibrous particulates associated with taconite ore — R. Wilson, E.E. McConnell, et al. (2008)
• Comprehensive assessment of exposures to elongate mineral particles in the taconite mining industry — J. Hwang, G. Ramachandran, et al. (2013)
• Mortality experience among Minnesota taconite mining industry workers — E.M. Allen, B.H. Alexander, et al. (2014)
• Cancer incidence among Minnesota taconite mining industry workers — E.M. Allen, B.H. Alexander, et al. (2015)
• Occupational exposures and lung cancer risk among Minnesota taconite mining workers — E.M. Allen, B.H. Alexander, et al. (2015)
• The relationship between various exposure metrics for elongate mineral particles (EMP) in the taconite mining and processing industry — J. Hwang, G. Ramachandran, et al. (2014)

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