Researchers are still years from knowing why Iron Range miners have been disproportionately struck by a rare form of asbestos-related cancer, but the Minnesota Department of Health will release new details today about those who have been affected.

So far, 58 Iron Range workers are known to have contracted mesothelioma, a form of lung cancer linked to asbestos exposure. At issue is whether those cases were caused by exposure to taconite dust, which contains some fibers that are chemically identical to asbestos.

Those who have contracted the cancer worked in seven mining companies, with most cases coming from the ranks of the two firms that employed the most workers, U.S. Steel and Pickands Mather.

Those mining companies were spread throughout the range and were not concentrated in the east, where taconite fibers are more likely to resemble asbestos.

"The fact is that this occurred throughout the Iron Range facilities," said Dr. Alan Bender, who heads the environmental epidemiology section that conducted the research. "What that means will be resolved through the next range of studies with the university."

The Health Department, which came under criticism this year after the Star Tribune reported that the department withheld the discovery of 35 additional mesothelioma cases for one year, said it is committed to obtaining funding for three research studies that could cost a total of $5 million and take up to five years to complete.

"We will be working with the university, the Legislature and possibly others to identify a funding source, and we hope to have that done by the end of the upcoming legislative session," said department spokesman Buddy Ferguson.

A 2003 Health Department study concluded that commercial asbestos located in boilers and other equipment at the mines was the most likely cause of the mesothelioma. But that conclusion has been challenged by mine workers and others, including former U.S. District Judge Miles Lord, who have said the department has not considered all of the possible factors.

Glenn Howatt • 612-673-7192