The state Health Department found that additional Iron Range miners had a deadly asbestos-related cancer, then sat on the information for a year.
The Minnesota Health Department suppressed research about additional deadly cancers among Iron Range miners for a year, even though a top government scientist warned that the findings raised significant new health issues.
The department discovered in March 2006 that a rare, asbestos-related cancer had stricken 35 more miners than the 17 previously known. All of the miners have died. The state didn't release the new information until March of this year, a decision that some health experts are now criticizing.
The findings sparked renewed concern about taconite dust and lung cancer among the 4,000 workers in the state's iron ore industry.
Health Department documents obtained by the Star Tribune show that officials had planned last year to disclose the information to mining unions, businesses, federal regulators and others. But state Health Commissioner Dianne Mandernach rejected those plans last fall.
Documents also show that the department feared that public disclosure of the findings would create controversy.
In an interview Wednesday, Mandernach defended the yearlong delay, saying the department had needed time to plan new studies of mining and disease.
The cancer, called mesothelioma, is deadly. It strikes the lung lining and develops decades after exposure to asbestos fibers.
Mandernach said that releasing the findings without having a plan for further studies could "excite and cause tremendous concern before you have all of your ducks in a row."
But public-health experts and others said the department shouldn't have waited.
"Whether or not they had a plan in place is neither here nor there," said Dr. Ian Greaves, an associate professor of environmental health at the University of Minnesota who is an expert in lung diseases.
"They're a public agency that serves the public, and I think it's overreaching to think they should take an attitude that they know best. ... This sounds very paternalistic in some ways."
Yearlong delay is unusual
For decades, mine dust has been a concern because some taconite fibers are chemically identical to asbestos. 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.
That contentious history is reflected in department e-mails, memos and notes released under the state public-records law. They show that officials worried about public reaction to the latest research, which covered 1997 to 2005.
"Many will believe that they confirm the health hazards of the miners that have long been feared and predicted," said a March 2006 talking-points memo by Dr. Alan Bender, who heads the environmental epidemiology section that conducted the research.
Another briefing paper, prepared last year for the commissioner, said: "Release of the findings is likely to generate demands that the government do more to protect workers."
Bender, who has long advocated more research into occupational hazards, urged at the time that the findings be released.