University of Minnesota health researchers began sending letters Monday to current and former taconite workers on the Iron Range to enlist them in a wide-ranging study of a rare cancer.

University medical experts are randomly selecting 1,200 taconite workers and 800 of their spouses for one of three health studies now under way to find out why so many Iron Rangers are dying from mesothelioma.

Four former railroad workers are seeking more than $1 million from five railroad corporations, alleging they developed asbestosis after they were exposed to asbestos and second-hand cigarette smoke during their employment.