The Minnesota Department of Health has identified four new cases of a rare cancer among former Iron Range mine workers.
Mesothelioma is a cancer of the lining of the lung, caused by exposure to asbestos. The disease occurs among iron mine workers at twice the expected rate.
Health Department spokesman John Stieger said cases were identified by comparing a database of mine workers with the state's cancer surveillance system.
"Mesothelioma can take as long as 40 or 50 years to develop, that's why we're just identifying these cases now in miners that worked in the mines quite a few years ago," Stieger said.
Stieger said the new cases were found by comparing a database of former mine workers with the state's cancer surveillance system.
"We had always anticipated that we would identify additional cases of mesothelioma among workers in iron mining industry, so we were not terribly surprised that we found these new cases," he said. "However it is important to provide this new data to UM, which is conducting a very comprehensive research study into this issue."
The four new cases bring the total to 63.
Researchers at the University of Minnesota are screening current mine workers, and have not identified anyone with mesothelioma in that group.