Steve McGrath grew up in Butte, and has long been one of the voices in the neighborhood asking whether the dust that settles on his roof and car includes a dangerous mix of toxic metals. He says that so far, he hasn’t gotten a satisfactory answer. (Katheryn Houghton/KHN)

BUTTE — Steve McGrath stood in an empty lot a block from his home watching for dust.

This story also appeared in Kaiser Health News

In this city nicknamed “The Richest Hill on Earth,” more than a century of mining left polluted soil and water that has taken decades to clean.

But at that moment, looking across the road toward Butte’s last operating open-pit mine, McGrath was worried about the air. “Here comes another truck,” McGrath said, pointing to a hillside across the street as a massive dump truck unloaded ore for the mine’s crusher. A brown cloud billowed into the air. “And there’s the dust.”

In the Greeley neighborhood, where McGrath lives, many people have a hard time believing the air they breathe is safe. A two-lane road separates the roughly 700 homes from the Continental mine, an open-pit copper and molybdenum mine operated by Montana Resources.

Residents have received assurances that the level of particulate matter in their neighborhood isn’t hazardous, but some doubt those standards protect human health. People breathe in particles all the time, but the size, abundance, and chemical makeup determine whether they’re dangerous. Now, the Environmental Protection Agency is evaluating whether its threshold for the density of harmful particulate matter should be lowered, saying it may not go far enough.

Al Shields of Butte shakes his head when asked whether he’s worried about dust coming from the mine nearby. “What people don’t understand is if the mine goes, Butte is done,” Shields says. Credit: Katheryn Houghton / KHN

McGrath, 73, grew up in Butte and has long been one of the voices in the neighborhood asking whether the dust that settles on his roof and car includes a dangerous mix of toxic metals. “Is this a health concern?” McGrath said. “We’ve never gotten a really satisfactory answer.”

For years, the company and the state Department of Environmental Quality have collected air samples in the neighborhood. The results have been consistent: Pollution levels don’t warrant alarm.

Montana Resources established a monitor to track metals in the air around Greeley, and an independent review found no threats to human health, which the state health department backed. However, additional studies, which government and mine officials have often bucked, have indicated potential problems — such as elevated levels of metals, including aluminum and copper, in the area and traces of arsenic and lead in the ground — and called for more testing.

This year, the nonprofit advocacy group Montana Environmental Information Center asked a contractor to review the data that Montana Resources and DEQ collected. Ron Sahu, the mechanical engineer who did the review, said not enough research has been done to determine conclusively whether the mine is harming Butte residents. According to Sahu, the data had multiple shortcomings, such as time gaps. He also said that one air-monitoring station may miss harder-hit areas and that the risk to residents of prolonged exposure to the dust is still unknown.

Ed Banderob, with the Greeley Neighborhood Community Development Corporation Inc., walks near the Continental mine in Butte. Banderob and some other residents of the neighborhood across the street are concerned the dust from the mine is polluting the air. Credit: Katheryn Houghton / KHN

On a recent night in Butte, Sahu presented his findings to mine officials, representatives of the state, a local health advisory committee, and a handful of Greeley residents. State health and environmental quality staffers repeated what has been said before: All the recorded emissions meet federal standards.

Even so, Sahu said, the pollution levels exceed the public health safety recommendations made last year by the World Health Organization. For example, the EPA’s maximum annual average for the finest particles is a concentration of 12 micrograms per cubic meter, while the WHO’s limit is 5. From 2018 through 2020, the Greeley air-monitoring station recorded annual averages that range from more than 7 to nearly 10, according to Sahu’s review.

The EPA is studying whether to lower its 12-microgram standard and expects to release any proposed changes this summer.

In the meeting, resident Larry Winstel said he didn’t care about the data. He held up a square sheet of plexiglass covered in dust. “This is what’s on my picnic table,” he said. “This is three weeks’ worth. How much of this is being deposited over a year?”

The manager of environmental affairs for Montana Resources, Mark Thompson, said the company goes beyond what’s required to mitigate dust. He said it uses 240-ton trucks to water the mine’s gravel roads and air filtration systems to trap particulate matter.

Thompson said he agrees more must be done to determine whether air in Greeley is unsafe and, if so, why. “If there is a problem in that community, I want to know about it,” Thompson said. “My son, my daughter-in-law, and my two baby granddaughters live a block from the main gate of the mine.”

Haley Rehm holds her 2-month-old baby in the doorway of her home just across the street from the Continental mine in Butte. Rehm didn’t think about the dust often until a recent test of her 2-year-old son’s blood found elevated lead levels. Credit: Katheryn Houghton / KHN

Butte became a gold and silver mining camp in the 1860s, and people traveled from around the world to work in the city. The area was the battleground of the Copper Kings in the 1890s as mine owners raced to extract the metal used to feed the country’s growing electrical infrastructure and manufacturing industry.

People who grew up in Butte and nearby didn’t often question what the presence of mines or smelters meant for their health. The extractive industries offered good jobs. Many are proud their city helped electrify the nation and produced as much as a third of the world’s copper supply during its heyday.

Atlantic Richfield Co., which bought the Anaconda Co., shut down the Butte mines in 1982. Butte and a stretch of the Clark Fork river, where the mining waste washed downstream, were designated a federal Superfund site in 1983. A few years later, Montana Resources began operating, and its jobs helped steady the town’s population at about 30,000. The cleanup of the historical lead, arsenic, and other contaminants continues today.

The boundary of that work borders the Greeley neighborhood to the west, while the Continental mine cups the neighborhood to the northeast. Some residents worry the mine’s operations add another layer of harm.

“I know about the air-monitoring station down here and that they say it doesn’t pick up anything dangerous,” said Bob Brasher, who has a view of the Continental mine from his front yard. “But I don’t see how it couldn’t when we have those days and you look out here and you can see the dust blowing this way and settling.”

Just down the road, Haley Rehm said she didn’t think about the dust until a recent test of her 2-year-old son’s blood found elevated lead levels. The cause isn’t clear — toxic metals can be ingested in multiple ways. But the mine’s proximity prompted Rehm to test her home for lead; she was still waiting for the results in May.

People often speculate that local cancer cases are linked to the area’s mining past and present.

Jeanette Cooksey, 70, can’t remember a time she wasn’t worried about the dust. It has especially been on her mind since she was diagnosed with stage 4 uterine cancer two years ago. “I have to wonder if living in this neighborhood my whole life has something to do with it,” Cooksey said.

A state health department analysis found the incidence rate for cancer from 1981 through 2010 wasn’t elevated in Silver Bow County compared with the rest of the state.

Not everyone is worried. For some people, even talking about potential health effects equates to an anti-mine mentality.

Al Shields rolled his eyes when asked whether the dust concerned him and nodded toward his clean trucks, saying they hadn’t been washed for days. “What people don’t understand is if the mine goes, Butte is done,” he said. “If you don’t like it, leave.”

Montana Resources employs 380 people and is a significant source of tax revenue. Those pushing for more research into the mine’s effects and what can be done about the dust have said they aren’t trying to close the operation. “We want a clean and healthy environment,” said Ed Banderob, with the Greeley Neighborhood Community Development Corporation Inc.

When Butte’s health advisory committee meets again in the fall, the state will share the air-sampling data it has collected in the hopes that staffers can answer lingering questions. Meanwhile, Montana Resources hopes to set up more air-monitoring equipment around the neighborhood by the end of the year.

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Katheryn Houghton, Kaiser Health News

Katheryn Houghton is Kaiser Health News' Montana correspondent. She owes her health reporting start to years spent in daily newsrooms, including those of the Bozeman Daily Chronicle and the Daily Inter Lake. She’s been an Association of Health Care Journalists fellow and a Solutions Journalism Network grantee. She is a graduate of the University of Montana.