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Mortality of workers in two Minnesota taconite mining and milling operations
W C Cooper1, O Wong, R Graebner
1Environmental Health Associates, Inc, Oakland, CA 94607.
Abstract:
Mortality during the years 1947 to 1983 was studied in 3,444 men employed for at least 3 months in Minnesota taconite mining operations during the years 1947 to 1958. During 86,307 person-years of observation, there were 801 deaths for a standardized mortality ratio (SMR) of 88 (US white male rates) or 98 (Minnesota rates). The 41 deaths from respiratory cancer were fewer than expected, the SMR being 61 (P less than or equal to .01) (US rates) and 85 (Minnesota rates). There were 25 respiratory cancers 20 or more years after first taconite employment, for an SMR of 57 (P less than or equal to .01) (US rates). SMRs for colon cancer, kidney cancer, and lymphopoietic cancer were elevated, but below the level of statistical significance. There was one death from pleural mesothelioma, 11 years after first taconite employment, in a man with long prior employment as a locomotive operator. The pattern of deaths did not suggest asbestos-related disease in taconite miners and millers.
Insights
Mortality among taconite miners showed no increased risk for respiratory cancer, with fewer deaths than expected. The study did not find evidence of asbestos-related diseases in this occupational group.
Area of Science:
- Occupational Health
- Epidemiology
- Environmental Health
Background:
- Taconite mining involves potential exposure to dust and fibers.
- Previous studies have raised concerns about respiratory health in mining populations.
Purpose of the Study:
- To investigate mortality patterns in Minnesota taconite miners.
- To assess the risk of specific cancers, including respiratory and asbestos-related diseases.
Main Methods:
- A cohort mortality study of 3,444 men employed in Minnesota taconite mining (1947-1958).
- Follow-up for mortality from 1947 to 1983, totaling 86,307 person-years.
- Standardized Mortality Ratios (SMRs) were calculated using US and Minnesota rates.
Main Results:
- Overall mortality was similar to general populations (SMR 88-98).
- Respiratory cancer deaths were lower than expected (SMR 61-85), particularly 20+ years post-employment (SMR 57).
- No clear pattern of asbestos-related disease was observed, including one mesothelioma case.
Conclusions:
- Taconite mining employment in this cohort was not associated with increased respiratory cancer risk.
- The findings do not support a significant link between taconite mining and asbestos-related diseases.
- Further research may be warranted for other cancer types with elevated, though non-significant, SMRs.