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40-year fiber debate renewed
NORTHSHORE MINING CO.: State regulators say fibers in the wastewater of a Silver Bay plant are not a significant health threat.
BY JOHN MYERS
NEWS TRIBUNE STAFF WRITER
Nov. 20, 2005 - Mineral fibers emitted from Northshore Mining Co.'s taconite processing operations aren't asbestos, but they're a close relative.
That issue has been considered by Minnesota Pollution Control Agency regulators, who on Tuesday will issue their recommendation on Northshore's plan to expand production in Silver Bay. The higher output will increase the number of fibers to be discharged as a byproduct. That won't create a health or environmental problem, PCA regulators said, but they also said the fibers aren't necessarily harmless.
The company wants to fire up a long-idled taconite processing line called Furnace 5 so it can annually make an additional 1.4 million tons of taconite. The $29 million expansion is temporarily on hold until the taconite market improves, but company officials are going ahead with the permit process.
Northshore's expansion is expected to add 30 jobs at the plant. But it's also rehashing a 40-year-old debate about asbestos-like fibers made famous when the facility was owned by Reserve Mining Co.
On Tuesday in St. Paul, the PCA's citizens board will decide three issues surrounding the expansion: the environmental review and separate air and water pollution permits.
The expansion would add 21 percent to Northshore's 6.5 million-ton capacity. Tailings also will increase, as will the volume of wastewater that carries mineral fibers. Northshore is proposing a 50 percent increase in the capacity of the Milepost 7 wastewater treatment plant, up to 7.5 million gallons per day.
The fibers are the same ones that caused concern in the 1970s, when Northshore's predecessor, Reserve Mining, was court-ordered to stop dumping its waste rock, called taconite tailings, into Lake Superior.
In Minnesota's most famous environmental battle, courts ruled that the amphibole fibers in the tailings may cause human and environmental health problems. The company was forced to dispose of its tailings in an on-land, contained basin -- Milepost 7 -- and to treat water leaving the basin before it goes into the Beaver River and, eventually, Lake Superior.
The operation, now owned by Cleveland-Cliffs Inc. and called Northshore Mining, continues to deposit tailings on land, treating the excess water as it leaves the basin.
PCA staff is recommending the permits be approved. They said a full-fledged environmental impact statement is not needed. State pollution and health regulators said the fiber increase won't create a significant environmental or health problem. The company has asked for an increase -- from 1 million parts per liter under current permits to as high as 6.8 million parts per liter under the proposed permit.
The level being released will remain below the Environmental Protection Agency's exposure limit for drinking water -- 7 million fibers per liter.
In public comments, people seemed to agree there's no need to worry. Only 10 out of 84 expressed opposition.
"I believe Cleveland-Cliffs will make every attempt to minimize the environmental impact," wrote Gary Zinter, a retired Silver Bay teacher, in support of the expansion.
While the fiber increase may sound like a major hike, it's mostly on paper. Northshore hasn't been able to meet the 1 million parts per liter standard imposed by the state years ago.
"It's reflecting reality. It's reflecting where the best available treatment technology can get them," said Mike Rafferty, PCA project manager.
Company officials said they will use "best available technology" as defined by the PCA "to ensure that the water entering the Beaver River meets strict pollution control limits. In some cases, such as for turbidity, the basin water discharge from the treatment plant is cleaner than the water in the Beaver River."
The company did not mention mineral fibers in any of its written responses to News Tribune questions for this story.
"Northshore Mining is committed to responsible environmental stewardship and invests significant human and financial resources to protecting the environment," Dayna Byrne, Cleveland-Cliffs spokesman, wrote in one response.
But others said that raising the bar so the company can meet a higher fiber limit doesn't seem right.
"The 1854 Authority questions if this adjusted limit for the release of amphibole fibers into the Beaver River will be protective of human health and the environment," wrote Darren Vogt, environmental biologist for the authority, a natural resources partnership among Ojibwe bands. "Furthermore, the environmental effects of increased releases into the Beaver River and Lake Superior are unclear."
"The appearance that the permit has been designed to fit the project needs significant review and explanation," said LeRoger Lind, a Two Harbors resident and member of the Save Lake Superior Association, later adding, "It's still the same issue as Reserve Mining 30 years ago. It's the same fibers."
Rafferty said the treatment facility removes more than 99 percent of the fibers before water is released to get the level below 6.8 million fibers per liter.
Health experts said the exposure level needed for possible health effects simply isn't known.
"We've looked at everything that's available out there, the literature from all the pertinent scientific studies, and can't find anything that shows levels this low are any kind of problem," said Hillary Carpenter, toxicologist for the Minnesota Department of Health. "Even with the increase in flow, there won't be any increase in what ultimately ends up in Lake Superior. It won't be detectable. And it certainly won't show up in drinking water."
Phil Cook, scientist at the U.S. Environmental Protection Agency's Duluth research lab, has been studying the mine's fibers for more than 25 years. While Cook said they could pose a potential health threat at high levels over long periods, the fibers won't be a threat at the levels being released.
"At 6.8 million fibers per liter, that's not going to create any public health threat, assuming we're still filtering drinking water coming out of the lake," Cook said.
That amount is far, far less than the 60 million fibers per liter found in Duluth drinking water during the late 1970s, Cook noted, when Reserve Mining was dumping raw tailings into Lake Superior, the city's water source. Those fiber counts spiked up to 600 million fibers per liter.
Over the years, Northshore officials have been quick and determined to note that the amphibole fibers in the ore, mined near Babbitt and processed in Silver Bay, are "non-asbestoform." While they are similar to asbestos, they are much shorter. Most studies seem to show that longer mineral fibers are more likely to cause cancers.
"Northshore's ore body has been mined for more than 40 years. Not one study has indicated that the ore poses a risk to Northshore employees or its neighbors," Byrne said.
Moreover, scientific evidence seems to show less occurrence of problems from ingesting fibers in water than from inhaling them.
But that doesn't mean shorter, taconite mineral fibers are definitively harmless when inhaled or ingested, several experts said. And state officials said the company is missing the point by arguing the taconite fibers aren't asbestos.
"The fibers that are killing people in Libby (Montana) are not technically asbestos either. That really isn't the issue," Carpenter said. "There's a whole host of (mineral fibers) that can be a problem that don't fall under the official definition of asbestos."
Carpenter added, however, that the exposure from Northshore fibers is far from the exposure levels from vermiculite mining in Libby -- people simply aren't coming in contact with as many fibers in Silver Bay, and the fibers aren't from the same kind of rock.
Others said it's too soon to call East Range taconite fibers safe. In some cases, it takes 50 or more years of exposure to exhibit disease from mineral exposure, Cook said. Carpenter noted that the epidemic of disease in Libby wasn't obvious for more than 70 years after the plant opened.
"It should not be inferred that there is no risk associated with the exposure of humans to short fibers such as those released by the Northshore Mining Company facility," the PCA noted in explaining the potential risk of the expansion. "Evidence suggests that the risk associated with exposures to fibers longer than 10 microns may be greater than exposure to shorter fibers. However, fibers shorter than 5 microns in length have some potential to cause cancer."
In its summary of the project, the PCA and Minnesota Department of Health said it's "unlikely" that the proposed increase in fibers from Northshore's wastewater will result in any health effects for people who drink water from Lake Superior, but also cautioned that "oral exposure to high concentrations of asbestos fibers may pose a small risk of causing cancer that is not quantifiable."
The expansion project also is expected to see a small increase in mercury emissions and particulate matter, PCA documents show.