Public health experts had long suspected that people in the taconite industry are at an increased risk for developing mesothelioma, because at least 82 taconite workers on Minnesota’s Iron Range have died from the rare but deadly cancer in recent years.
Researchers already knew that the rate of mesothelioma in the communities surrounding taconite mines in Minnesota was three times higher than elsewhere in that state. A new study has just definitively linked the taconite industry itself to a 3 percent increased risk of mesothelioma — a risk that increases with cumulative exposure in the workplace.
Taconite is an iron-bearing sedimentary rock which contains finely dispersed iron oxide which can be refined into usable iron. After it is mined, the refining process requires the rock to be pulverized into a fine powder so that the iron can be separated out by magnets. It is then molded into pellets and fired in kilns to make the pellets durable before sale to the steel industry. While taconite does not contain asbestos, both the rock and the dust contain fibrous materials similar to those in asbestos.
According to the researchers, very few taconite mineral fibers are the same size of the asbestos fibers known to cause asbestosis, asbestos-related cancer, mesothelioma and other diseases. The fibers in taconite are longer and are called “elongated mineral particles” or EMPs. They cannot be sure, however, that the EMPs are responsible for the increased mesothelioma risk.
People who worked most directly with taconite in its most dust-producing stages experience higher levels of exposure, and the highest exposure levels were among workers operating agglomerators, where the rocks are mechanically sifted, and those in the kiln discharge area.
The study did find an association between how long people worked in the taconite industry and their risk of developing mesothelioma. However, they found little evidence that the EMPs routinely travel outside the mines and plants. Asbestos dust is readily carried home on clothing, and this second-hand exposure has been responsible for many asbestos and mesothelioma deaths.
Mesothelioma is rare, and symptoms often don’t appear until decades after exposure to asbestos or similar materials. Nevertheless, workers have a right to know whether the products they produce could cause deadly cancers, and more work needs to be done.
Source: Duluth News Tribune, “Study confirms link between mesothelioma, taconite,” John Lundy, April 13, 2013