News Release
FOR IMMEDIATE USE
March 7, 2003
Contact:
Dr. Alan Bender
Chronic Disease
& Environmental Epidemiology
(612) 676-5216
Buddy Ferguson
MDH Communications
(651) 215 -1306
Study finds that “commercial” asbestos offers likely explanation
for high respiratory cancer rates in northeastern Minnesota
On-the-job exposure to asbestos – through activities that are not unique to the mining industry – offers “a
likely explanation” for high levels of a type of respiratory cancer in northeast Minnesota, state health officials
say.
That finding comes from a study by the Minnesota Department of Health (MDH), which attempted to
account for elevated levels of mesothelioma in a seven-county area of northeastern Minnesota.
Mesothelioma is a relatively rare type of respiratory cancer, found almost exclusively in people known to
have been exposed to asbestos. Between 1988 and 1999, 81 men in that part of the state were diagnosed with
mesothelioma. Normally, around 45 men would be expected to develop the illness in a population that size,
over that time period.
There was no elevation in the occurrence of mesothelioma in women, providing additional evidence that
the high rate in men was occupationally-related.
Findings of the study were released today in Virginia, at a meeting of the Occupational Respiratory Disease
Information System (ORDIS) Advisory Work Group.
The Work Group played a critical role in designing and conducting the study, according to MDH officials.
Members of the Work Group included representatives of labor, industry, government, the education
community, and retired mine industry workers.
After identifying and studying a group of 17 men who had developed mesothelioma – and who had also
been employed in the mining industry – MDH investigators concluded that the group had enough occupational
exposure to “commercial asbestos” to account for their illness. Exposure to commercial asbestos can occur
through activities like plumbing, carpentry, boiler operation, and maintenance work. Those activities are found
in – but are not unique to – the mining industry.
After reviewing available information about the jobs held by the 17 men, MDH investigators concluded
that most of them probably did work that involved on-the-job exposure to commercial asbestos. Investigators
did conclude that one of the men may have held a job that – based on previous research – may have involved
high levels of exposure to dust from mining operations.
Taconite dust from mining operations had been a suspected source of exposure to asbestos-like mineral
fibers. However, based on the work experience of the men in the study, MDH investigators concluded that
commercial asbestos exposure was the most likely explanation for their illness.
-more-
MDH Communications Office • 85 East Seventh Place • Suite 400 • St. Paul, MN 55101 • (651) 215-1300
MDH news releases can be found at http://www.health.state.mn.us/news/news.html
Respiratory Cancer Study – page 2
Investigators believe that occupational exposure to asbestos partly explains the general elevation of
mesothelioma rates among men in northeast Minnesota. They noted that the elevation can also be partly
explained by the fact that, from 1958 to 1974, over 5,000 area residents worked at a plant in Cloquet that
manufactured asbestos board and ceiling tile.
The authors of the MDH study were quick to point out that the study does not provide a comprehensive
picture of occupational health issues in the mining industry.
“The focus of this study was relatively narrow, and it’s important to understand that point,” said Dr. Alan
Bender, who heads the Chronic Disease and Environmental Epidemiology Section at MDH. “If possible, we
wanted to find out why mesothelioma rates were elevated in this part of the state. That’s all we attempted to do,
and all we were set up to do.
“We did not attempt to do a comprehensive study of commercial asbestos use in the mining industry, and
its implications for the health of workers,” Dr. Bender noted. “We also didn’t attempt to do a comprehensive
examination of health issues affecting iron miners. We didn’t look at other types of cancers, or other types of
respiratory diseases, or at other health risks that could be associated with breathing in mineral dust from
taconite ore. Additional studies – and different kinds of studies – would be needed to do that.”
Dr. Bender also pointed out, however, that the new study is the first to document the occurrence of
mesothelioma in mining industry workers. Previous studies had attempted to look at mesothelioma and other
forms of cancer in that industry by examining death records. The MDH study used data from the Minnesota
Cancer Surveillance System (MCSS), which gathers information on new cases of cancer in the state as they are
diagnosed.
The 17 men included in the study were identified by examining records for men diagnosed with
mesothelioma in Minnesota, and comparing that list with a roster of 72,000 people who had worked in the
mining industry in the northeastern part of the state from the 1930s to1983. The University of Minnesota
School of Public Health originally compiled the roster of mine industry workers in the early 1980s, for use in a
different study. That university undertook that project with support from the Iron Range Resources and
Rehabilitation Board (IRRRB).
-MDH-