More Iron Miners Diagnosed with Mesothelioma in Minnesota

Minnesota officials say they have identified four more former iron miners who have been diagnosed with mesothelioma cancer as part of an ongoing respiratory study of the state’s mining industry.  

The diagnoses of the four miners brings the total number of former Iron Range Mine workers who have the deadly lung disease to 63. The cases were discovered through a review of data from the Minnesota Cancer Surveillance System. The state is working with the University of Minnesota School of Public Health to assess the extent and causes of mesothelioma cancer from about 1,200 current and former taconite miners and their spouses.

Taconite is a flint-like rock that contains high amounts of iron. In the mining process the rocks are ground to powder and the iron dust is removed using powerful magnets. There has been a long-running debate as to whether the high number of mesothelioma cases can be attributed to the taconite, or to exposure to asbestos utilized in pipes and boilers throughout the taconite mines.

Mesothelioma is a rare form of cancer found in the lining of the chest and lung. The only known cause of mesothelioma is asbestos, and it is often not diagnosed for 20 to 40 years after exposure. As a result of the long latency period, the cancer is very advanced when it is diagnosed and life expectancy with the disease is limited.

Asbestos was widely used in a variety of manufacturing and construction applications throughout the last century, with use peaking in 1973. Most uses of asbestos were banned in the mid-1980s.

The University of Minnesota says about 1,100 taconite workers have been screened as part of the Minnesota Taconite Workers Health Study, and they anticipate they will finish screening all the workers sometime this summer. A 2003 study from the university concluded that asbestos was the cause of the taconite miners’ mesothelioma, but critics say that taconite has asbestos-like properties and have intensely disputed the study’s findings. It is hoped that the current study underway will be able to definitively determine the source of the mesothelioma cancer.