On Tuesday, the state Department of Health discovered four more cases of an unusual asbestos-related cancer among Minnesota taconite workers.

The department says that it identified the cases amid a group of 69,000 people who worked in the state's mining industry from the 1930s to 1982.

The cases were found during an evaluation of information from the Minnesota Cancer Surveillance System about the workers as part of a bigger research by the University of Minnesota.

The reality that boilermakers often worked in restricted areas with the deadly material on a regular basis accounted for their risk.

Even family members are prone to danger for mesothelioma from boilermakers who took the noxious substance home in the form of asbestos dust on their work attire.

National Cancer Society data reveals that boilermakers, together with shipbuilders, plumbers and electricians, have a much higher frequency of getting mesothelioma than other occupations, because of the possibility of asbestos exposure. And since mesothelioma can take 30 to 50 years to develop after exposure, even retired boilermakers remain at danger of acquiring it.

The total number of workers diagnosed has reached 63 after the addition of these four new cases.

The new cases will be integrated into the university's Minnesota Taconite Workers Health Study.