Mesothelioma task force updates public on progress

LTV taconite plant
The former LTV taconite facility is pictured from a distance, north of Hoyt Lakes.
MPR Photo/Bob Kelleher

Mesothelioma is a rare cancer that attacks the lining of the lung, caused by exposure to asbestos. Taconite workers in northeastern Minnesota get mesothelioma at twice the expected rate.

Over the years, several attempts have been made to explain why. But none went into the details this group is delving into.

"We'll have answers we can stand behind."

Dr. Jeff Mandel, in the School of Public Health at the University of Minnesota, said scientists are working on several fronts.

Taconite fiber
This electron microscope photo shows a taconite fiber breaking up into smaller fibers in rat lung tissue. The state Health Department is conducting studies to see if taconite fibers can cause mesothelioma, a rare form of lung cancer which is usually associated with asbestos exposure.
Photo courtesy of Dr. Philip Cook, U.S. EPA

One team is trying to get accurate measurements of the types and amount of dust workers are exposed to in taconite processing plants.

Another is identifying the causes of death and cancers in a database of nearly 70,000 mine workers that was created in the 1980s.

Geologists are studying the minerals in the mines, to sort out exactly how they might compare to the commercial asbestos that is known to cause mesothelioma.

And this spring, the University will contact about 1,200 miners and 800 spouses of miners, to do a detailed health assessment, including X-rays and CT scans.

That's the study that a lot of people are most interested in.

The crusher, Hibbing Taconite
A 240 ton mining truck is dumping its load of taconite rock into the crusher building at Hibbing Taconite. The first step in processing taconite is to crush the rock into a more manageable size.
MPR Photo/Bob Kelleher

Dave Trach is with a steelworkers retiree group. He organized a lung screening for retirees. He said that screening turned up a lot more than the annual checkups that were offered by the company.

"Nobody ever turned up with anything, all the 38 years I was there, one individual got silicosis and that was it. When we started the screening, all of a sudden here was all these mesothelioma cases, cancer cases, colon cancer," Trach said.

Dr. Ian Greaves said it takes a special kind of radiologist, called a B-reader, to recognize the problems caused by dust particles.

"It's possible that some of those routine films were read by people who maybe weren't as proficient as a B-reader, and also the quality of those films are very important," Greaves said.

But Dave Trach has watched several people die of lung diseases, and he can't help wondering about those company checkups.

Northshore plant
The Northshore Mining processing plant is just below the town of Silver Bay. The company has been monitoring fibers from the plant for nearly thirty years. The fiber numbers have declined as the mine has added pollution control equipment.
MPR Photo/Stephanie Hemphill

"I don't like to say that they were hiding it. Maybe they just didn't know what to look for. I don't know."

The current study is going to have three expert radiologists look at each x-ray, and when they interpret them differently, they'll all look at them together and try to reach a consensus.

An earlier study by the Minnesota Department of Health concluded that the 58 taconite workers who got mesothelioma most likely got it from exposure to commercial asbestos, which was used in the mines just as it was in many other industries.

So how will the current study sort out whether the culprit is commercial asbestos or taconite dust? Dr. Greaves said they'll get detailed work histories from the people in the study.

"We've included in the work history a lot of questions about incidental asbestos exposure or work with asbestos. And we're hoping that we'll be able to identify those people who have had significant asbestos exposure, and incorporate that into our analysis," Greaves said.

Several audience members thanked the researchers - not just for the work they're doing, but for coming to the Iron Range on a cold night in December to talk about it.

Dave Trach, the LTV retiree, said it will be hard to wait another year or even more before the results are in, but it will be worth it.

"People get... if something don't happen right away, they get all shook up, and mistrust even sneaks in a little bit, so they're not sure whatever they're doing is what they should be doing. I think we should be doing this, and I think it's going to have benefits for people that work in the mines from now on."

The task force reports to the Legislature in February.

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