The results of a five-year, $4.9-million study into the link between taconite mining in Minnesota’s Iron Range and mesothelioma provided a mixed bag of results. Scientists confirmed a definite link between the taconite industry and an increased risk of mesothelioma, a deadly cancer that has previously been associated exclusively with asbestos exposure. But the study does not adequately answer the question of “why” or “how.”
A public meeting was held in Mountain Iron, Minn., April 13, to provide concerned workers and residents to the nearby mines with preliminary results from the most comprehensive study of taconite workers’ health to date. The study was commissioned in 2008 by the Minnesota Legislature after research provided evidence of much higher than normal incidents of mesothelioma among taconite mine workers. The Taconite Workers Health Study was directed by the University of Minnesota School of Public Health, in partnership with the Medical School and the Natural Resources Research Institute at the University of Minnesota Duluth.
Going into the study, researchers knew the rate of mesothelioma was three times higher than that of the general population of Minnesota. According to a report by the Duluth News Tribune, researchers confirmed that for every year a worker spent in the industry, his or her risk of mesothelioma increased by 3 percent. Research also indicates taconite workers have a higher-than-expected risk of all types of cancer, as well as heart disease.
However, researchers were puzzled by the lack of traditional asbestos-sized mineral fibers present in samples. Instead, they found fibers they call “elongated mineral particles,” or EMPs. But, they say they can’t be sure that EMPs cause mesothelioma and therefore are not certain that the dust from taconite mining causes mesothelioma.
The study does seem to indicate that spouses and family members of taconite workers, as well as residents in close proximity to taconite mines, are not in any significant danger. Researchers say air quality around the mines is good, and they feel any secondary exposure to taconite dust would be within safe limits.
It was a disappointing report for many in attendance, who told the Duluth News Tribune they felt “the ‘buts’ and ‘howevers’ sprinkled through the researchers’ presentation” left the door open for doubt, and left as many questions unanswered as resolved. Many miners in attendance said they already have lung disease and abnormalities in their lungs, and they fear the long latency period of mesothelioma – which can be as much as 30 years – leaves them a ticking time bomb that the study just can’t see yet.
Researchers say this initial report is only the “beginning of the end” of the study, and more data will be forthcoming.
“This is a landmark study for Minnesota and the Iron Range,” said John Finnegan, Ph.D., dean of the School of Public Health. “Our goal was to begin to answer questions around how mining and taconite processing have impacted the health of Minnesotans. These studies have started to uncover those answers.”