University of Minnesota Releases Final Minnesota Taconite Workers Health Study

Monday, December 1, 2014

The University of Minnesota today released the final report of the Minnesota Taconite Workers Health Study with further analysis of lung cancer and mineral fiber exposure, and a series of recommendations to monitor and prevent disease for workers in the taconite mining industry.

The final report will be shared at a community meeting Monday, December 1 at 4:30 p.m. at the Hibbing Memorial Building, located at 400 E. 23rd Street in Hibbing, MN 55746. The meeting is open to the public and will include presentations from the U of M School of Public Health and UMD Natural Resources Research Institute researchers. 

Beginning in 2008, researchers looked at taconite workers’ exposures to very small, needle-like fibers called elongate mineral particles (EMPs) and other common workplace exposures to dusts from taconite operations to see if lung diseases in miners were related to these dusts. A preliminary report released in April 2013 showed that taconite workers had higher than expected death rates from three diseases: mesothelioma (a cancer of the lining around the lung), lung cancer and heart disease when compared to the general population in Minnesota. While there was a link between working in the taconite industry and mesothelioma, the role of specific exposure was not clear.

Additional analysis was conducted over the past year regarding the higher than expected death rates from lung cancer and mesothelioma. The April 2013 analysis found  a general link between exposure to EMPs and mesothelioma.

Researchers also tried to analyze risk posed by different sizes of the fiber-like EMPs. Regulatory agencies measure EMPs that are longer than 5 microns (one millionth of a meter). U of M researchers looked at risk of lung cancer and mesothelioma if exposed to EMPs longer and shorter than 5 microns, but their analysis could not separate these effects.  No link was found between EMP exposure, or silica exposure, and lung cancer.

The authors of the report made recommendations for the workers, mining companies, unions and Iron Range health care community designed to assist in the safeguarding of future worker health.

“Mining is of great importance to the people of Minnesota and to our state’s economy,” said John Finnegan, Ph.D., Dean of the School of Public Health. “The state invested significant funds and time into the Taconite Workers Health Study and we felt it was important to indicate follow-up activities in order to continue to improve the health and safety of all miners moving forward.” 

The study found that spouses of taconite workers had no increased evidence on chest x-ray of lung scarring, compared to the broader general public.

"We gained valuable perspectives through this research,” said Jeffrey Mandel, M.D., M.P.H., a School of Public Health environmental health expert and principal investigator of the study. “The recommendations we made are intended to further improve the  understanding of disease in taconite miners.”

About the Taconite Workers Health Study
The Minnesota Taconite Workers Health Study was formed in response to an apparent excess of mesothelioma discovered by the Minnesota Department of Health among taconite workers. Tasked with investigating this finding and addressing growing concerns from citizens and legislators representing the Iron Range, several studies were conducted by University of Minnesota researchers.

The overall objective of the Minnesota Taconite Worker Health Study was to determine whether dust-related lung disease, including mesothelioma, lung cancer and non-malignant respiratory disease, might be related to working in the taconite industry.

The study had five main components, including 1) an occupational exposure assessment, 2) a mortality (cause of death) study, 3) cancer incidence study of lung cancer, 4) a respiratory health survey of taconite workers and spouses, assessing non-cancerous respiratory disease and 5) an environmental study of airborne particulates. 

Each study component has utilized an external peer-review process with science advisory boards that have been involved in the projects since the beginning and each of the study's five components provide a perspective that is important to the interpretation of the overall worker health status.