By Katheryn Houghton, Kaiser Health News
BUTTE, Mont. — Steve McGrath stood in an empty lot a block from his home watching for dust.
In this southwestern Montana 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.
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.