St. Paul, MN-Iron Range Mines

For decades, mine dust has been a concern because some fibers in taconite ore from the eastern Iron Range are shaped like asbestos fibers. Mine operations also used commercial asbestos on such things as pipes and boilers, creating another source of exposure.

In 2003, Health Department researchers found that 17 miners had developed mesothelioma between 1988 and 1996, and that commercial asbestos, not taconite dust, was a more likely culprit. Some critics said the Health Department didn’t look hard enough at mine dust.