Researchers are trying to determine whether fibers found in taconite mined near Lake Superior might cause cancer. Taconite is a type of iron ore. The microscopic fibers found in some taconite rock are a lot like asbestos, and asbestos causes cancer and other serious lung diseases. Research is now underway that could determine whether the fibers in taconite can cause cancer too. The question is a classic example of the uneasy balance between protecting health and creating jobs. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:
Researchers are trying to determine whether fibers found in taconite mined near Lake Superior
might cause cancer. Taconite is a type of iron ore. The microscopic fibers found in some
taconite rock are a lot like asbestos, and asbestos causes cancer and other serious lung diseases.
Research is now underway that could determine whether the fibers in taconite can cause cancer
too. The question is a classic example of the uneasy balance between protecting health and
creating jobs. The Great Lakes Radio Consortium’s Stephanie Hemphill reports:
The fibers in taconite first made big news thirty years ago. Reserve Mining Company was
dumping its waste rock in Lake Superior, and the fibers turned up in Duluth’s drinking water.
People worried, and started drinking bottled water, until a special filtration plant was built.
Reserve was forced to dump its waste rock on land.
But the jury is still out on whether the fibers are dangerous.
Phil Cook is one of the people who discovered the fibers in the water supply. He’s a chemist at
the National Water Quality Lab in Duluth. He studied the fibers for years.
They’re so small, you can’t see them even with a regular microscope. Cook and his team had to
use an electron microscope to get a handle on the fibers.
“Hundreds of hours of looking at many fields of view and counting particles of all sizes and
shapes and identifying them specifically as to what their mineral nature was.”
Some of the taconite fibers turned out to be more cancer-causing than others. The most
commonly occurring fibers were less dangerous.
But Cook found that some of the fibers caused even more cancer than asbestos. After two years
of experiments on lab rats, Cook found the most dangerous taconite fibers had splintered off,
multiplying the number of fibers in the rats lungs.
“So there was some kind of slow leaching going on while the fibers were in tissue, and blocky
particles would become thinner fibers. So the number of fibers were increasing and the dose was
But the question is, does the same thing happen to people, and are people exposed to enough of
the fibers to worry about cancer?
NorthShore Mining Company currently operates the former Reserve mine and processing plant.
NorthShore monitors its fiber emissions. Millions of fibers pour from the smokestacks. But at
monitoring stations about a mile away, the numbers drop to a background level comparable to
cities out of the area.
But some people worry even that level could make people sick.
There are no national or state standards for fibers in the air.
There are some rules for workplaces. Miners and taconite workers are exposed to a lot more
fibers than people who live nearby.
Northeastern Minnesota has a much higher rate of mesothelioma than the rest of the state.
Mesothelioma is a rare form of lung cancer caused by asbestos. Some miners are concerned
taconite could cause mesothelioma too.
The state Health Department recently completed a study of taconite workers who died of
mesothelioma. The study found most of them were exposed to commercial asbestos used as
insulation as well as taconite dust. The study concluded the commercial asbestos was the most
likely cause of the miners’ disease.
But the study looked only for mesothelioma. Some miners say it should have looked for other
diseases too. David Trach is president of a Steelworker retiree group. He says 450 former mine
workers got x-rays, and 30% of them had some kind of lung abnormality. Only a very few of
them had mesothelioma.
“We’ve got to search out for those young miners that are working now so they don’t end up like
some of my friends did at LTV Steel that are in their 60s and 70s, and can hardly breathe.”
The Minnesota Health Department has file cabinets full of information about the health of miners
and taconite workers. But there’s no money to study the data looking for other lung diseases.
That’s because last year the Minnesota state legislature eliminated the money for the project.
There’s a lot riding on whether taconite fibers are safe. Officials in the area where NorthShore’s
plant is located, would like to use the plant’s waste rock to build roads, which would spread the
taconite fibers throughout the county. Until now the company has been prohibited from selling
its waste rock by the court ruling in the Reserve case.
Also, several companies have been prospecting in the region. New mines for copper, nickel, and
other minerals could provide much-needed jobs in a region hit by mine closures and cutbacks in
the taconite industry. But they could also be digging into the same rock where the taconite fibers
After the scientific studies are published, the Minnesota Health Department will conduct a
formal assessment of the risks – if any – of taconite fibers.
For the Great Lakes Radio Consortium, I’m Stephanie Hemphill in Duluth.