States join to block lower air standards near taconite mine

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 30 years. The fiber numbers have declined as the mine has added pollution control equipment.
MPR Photo/Stephanie Hemphill

The state attorneys general in Minnesota and Wisconsin are joining environmental groups to stop Northshore Mining Co. efforts in federal court to lower the standard for fibers in the air near the company's Silver Bay taconite plant.

The states and environmental groups vehemently oppose the company's motion to drop the standard, set in 1974, for asbestos-like fibers in the air near the taconite plant along the shore of Lake Superior.

Some say such fibers, found in taconite dust in the eastern parts of the Iron Range, may cause health problems, particularly lung ailments like mesothelioma.

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

The current, court-ordered standard requires Northshore to keep fibers in the air near Silver Bay at or below the average level of fibers in St. Paul air. That comparison was developed because no human health standard has been set for how many taconite dust fibers are safe to breathe.

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"This court should decline Northshore's invitation to put Lake Superior residents at higher risk of deadly diseases than is faced by other Minnesotans," read a brief filed in federal court by the Minnesota Center for Environmental Advocacy.

Last year, the Minnesota Pollution Control Agency and state courts refused to drop the fiber comparison requirement, prompting Northshore to ask the federal court to intervene. A hearing is set for Thursday in federal district court in St. Paul.

The company claims that the comparison between Silver Bay and St. Paul air is outdated, and that the fibers pose no human health risk. Officials with Northshore say its taconite doesn't contain any asbestos, and that updated pollution control equipment has reduced fiber levels enough to comply with court orders without the comparison standard.

The company contends that dropping the standard won't result in increased fibers in Silver Bay, but would end an unfair comparison to fluctuating St. Paul fiber levels.

The MPCA has changed the comparison between Silver Bay and St. Paul air "into an undefined, constantly shifting, retroactive ambient air standard devoid of any scientific basis," the company noted in court documents filed last week.

But in a court brief filed for Minnesota Attorney General Lori Swanson, state officials said the company wants to eliminate the only real standard to protect human health in the region from possible ill effects of the fibers.

"Northshore's motion is nothing more than a subterfuge to collaterally attack ... efforts to reduce Northshore's excessive asbestos fiber emissions," the court document states.

In another brief, Wisconsin Attorney General J.B. Van Hollen noted that recent reports from the Minnesota Department of Health show unusually high levels of mesothelioma in the region. The disease is caused only by exposure to asbestos fibers.

(Information from: Duluth News Tribune, http://www.duluthsuperior.com)