MINNEAPOLIS, July 27 (UPI) -- Workers in Minnesota's taconite industry are being asked to take part in a study to determine why so many of them are getting a rare cancer, researchers say.
University of Minnesota scientists said letters began going out Monday to current and former employees of mining companies that extract the iron-bearing rock from the earth of northern Minnesota, the Minneapolis Star Tribune reported.
The mystery is why higher-than-expected numbers of the workers have developed -- and succumbed to -- mesothelioma, a cancer usually seen in those exposed to asbestos.
The researchers plan to spend five years and nearly $5 million trying to answer that question.
The letters going out to thousands of taconite workers and their spouses ask them to go through a screening process, regardless of health status.
The researchers have spent the past year accumulating data and will comb through the health and death records of 68,000 living and dead miners.
The School of Public Health researchers also intend to do health assessments on 1,200 current and retired workers and 800 of their spouses.