Talc Miners at Risk of Mesothelioma

New York Talc Miners Diagnosed with Mesothelioma After Asbestos Exposure

According to a recent article published in the American Journal of Industrial Medicine, talc miners should be added to the list of occupations at risk of mesothelioma. The article recapped a study that examined the work history and medical diagnosis of several talc miners in upstate New York. At least 13 miners and millers in that area had been diagnosed with mesothelioma since the 1970s though nobody could directly connect their exposure to asbestos.

In fact, a previous study by Honda et al. concluded that the miners' mesothelioma was not likely caused by the talc ore dust that these men came into contact with and inhaled during the course of their workday.

Doctor Murray Finkelstein of the Department of Family and Community Medicine at the University of Toronto in Ontario was not satisfied with this conclusion and reexamined the Honda data and also a study compiled by Mindy Hull of the Department of Pathology, SUNY Upstate Medical University in Syracuse. Hull uncovered even more mesothelioma diagnoses within this small population of miners. Indeed, since the Honda study was published, an additional 5 miners were diagnosed with mesothelioma. That brought the rate of mesothelioma in this isolated population as high as 11 times more than in the general population.

Clearly something local was causing an excess of asbestos disease regardless of what previous researchers concluded.  Upon further examination,  Dr. Finkelstein discovered that the men indeed had been exposed to asbestos, that they had two distinct types of asbestos mineral within their lung tissue: anthophyllite and tremolite.

Both tremolite and anthophyllite asbestos are common and are often found as contaminants in other rock formations and occur naturally throughout the world.  While not all forms of anthophyllite are considered asbestos, the fibrous forms of the mineral are. In fact, this type of asbestos has been mined worldwide – notably in Finland and Japan – for years and can commonly be found in floor tiles and other composite flooring. The U.K. especially is dealing with an excess of these anthophyllite contaminated building products.

Tremolite is perhaps more common than anthophyllite and while there are multiple forms of tremolite, some of which are not classified as asbestos, the fibrous form of the mineral does pose a health risk. Tremolite has been positively linked to cases of asbestos cancer and diseases and is commonly found mingled in deposits of other forms of asbestos, such as vermiculite and chrysotile. Tremolite, as Finkelstein was quick to note, is also a common contaminant in talc.

While other types of mining have been added to the list of jobs at risk for asbestos exposure, talc mining has typically not been associated with malignant mesothelioma. However, it’s clear from the relatively high concentration of miners in New York diagnosed with asbestos that there is a very real risk associated with the industry.

Finkelstein concluded his paper with a quote from Mindy Hull’s previous work: "New York talc exposure is associated with mesothelioma, and deserves further public health attention."

Source: Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada; Program in Occupational Health and Environmental Medicine, McMaster University, Hamilton, Ontario, Canada. Am. J. Ind. Med. © 2012 Wiley Periodicals, Inc.

Summary:  There is controversy about the potential for dust from the talc mines and mills of New York State to cause mesothelioma. Honda et al. published a study of mortality among New York talc workers and concluded that it was unlikely that the two deaths from mesothelioma were caused by talc ore dust. However, fibers of tremolite and anthophyllite have been found in the lungs of talc workers and Hull concluded that "New York talc exposure is associated with mesothelioma, and deserves further public health attention."   There were at least five new cases of mesothelioma in the cohort and mesothelioma incidence rates were at least five (1.6-11.7) times the rate in the general population (P < 0.01).   Conclusions: (1) mesothelioma has been diagnosed among members of the cohort at a rate in excess of that in the general population; (2) fibers of tremolite and anthophyllite have been detected in dust and the lungs of talc workers; and (3) these fibers are known causes of mesothelioma. It is prudent, on the balance of probabilities, to conclude that dusts from New York State talc ores are capable of causing mesothelioma in exposed individuals.