BUTTE — Deer leap through fields and fish swim the stream where a wood-treating plant once leached vast amounts of cancer-causing chemicals into Silver Bow Creek.
State officials say the Montana Pole and Treatment Plant Superfund site cleanup in Butte is making good progress.
But members of the federally funded Citizens Technical Environmental Committee are unconvinced. The group is balking at a state plan to cap parts of the site with clean soil, saying toxic compounds called dioxins still pose serious threats, especially to a nearby neighborhood.
“I’m not an engineer or a chemist, but according to all the research I’ve done I have yet to see any scientific study that says there are acceptable levels of exposure to dioxin,” said John Ray, CTEC president and a professor of public policy and political science at Montana Tech.
The cleanup is raising new questions about thresholds for pollutants in water and soil, and whether the cleanup is being done the best way possible.
Decades of toxic waste
The Montana Pole and Treatment Plant, located near Montana Street and Interstate 15-90, began operations in 1946.
It closed in 1984 when a person walking along Silver Bow Creek noticed oil leaching into the water.
Officials eventually realized a 42-acre plume of byproducts from the chemicals used to treat fence posts and railroad ties was polluting not only the creek, but soil and groundwater.
In the fallout of litigation over the contamination, a plan was set in 1993 for cleaning up the site and thresholds were set for how much pollution would continue to be allowed to seep into the creek. Dioxin, an incredibly toxic compound that is the primary component in Agent Orange, remains — although at miniscule levels.
Still, stakeholders have different ideas about just how much dioxin is acceptable, mostly because of shifting perceptions as science has changed over the past 20 years. The groundwater treatment system at the site is meeting standards set in 1993 — but dioxin levels are still more than 100 times higher than what the DEQ now finds acceptable, according to a March report produced by Ian Magruder of Kirk Engineering & Natural Resources.
“They had a different understanding of dioxin toxicity (in 1993) than they do now,” said Magruder, a hydrogeologist and technical adviser to CTEC. “Dioxin is now considered more toxic. The EPA and the DEQ are supposed to go back and consider the new science to determine if new standards are appropriate. Dioxin quality standards are moving targets because they are the subject of ongoing research.”
The EPA is re-evaluating acceptable dioxin levels. Lisa Dewitt, the DEQ Superfund project manager, said once that information is available, it may be applied to the pole plant.
Magruder said that if Silver Bow Creek were a perfectly pristine stream with no dioxins, the output levels from the pole plant would be cause for concern.
“Montana Pole is not degrading Silver Bow Creek because Silver Bow Creek already has dioxins in it,” he said. “The water being released from Montana Pole is perfectly fine for people to drink it. It’s not just a Montana Pole issue and Montana Pole is not the source of this problem. To a certain degree we live in a polluted world.”
Magruder noted that Missoula is actually Montana’s most dioxin-polluted city, owing to the now-defunct paper mill in Frenchtown.
But the DEQ also has said dioxin levels in the soil at the site will never meet the new standards and will need to be capped. It’s that discrepancy that’s raising red flags for CTEC.
“At the time of the record of decision we were promised biological treatment of the site,” Ray said. “Somewhere along the line they changed from active treatment to containment and institutional controls. So now the very toxic material will stay on site.”
Ray said that the cleanup cost has become the most important factor to government regulators, not the quality of the cleanup. “You need to find the best remedy and the more efficient way to pay for that, not the cheapest remedy,” he said.
But Dewitt disagrees.
“Cost does play into it because I have a fixed pot of money,” Dewitt said. “But I’m not looking at the cheapest route. I’m looking for something that’s protective and fits the budget. But protective is most important.”
Cleanup vs. containment
And when it comes to protecting, the DEQ says capping may be the best method for the Montana Pole and Treatment Plant site.
The soils are treated, replaced in their original areas, covered with a clean soil cap and seeded with grasses. It’s a containment option that has been used all over Butte.
That's not good enough, Ray said.
“We have a situation where the most toxic substances in Butte are to be covered with the least amount of soil,” he said. “Caps, as we have seen in Butte already, are susceptible to failure by means of bio-irrigation, advection, desiccation, erosion, weathering, bio-intrusion and stabilization problems. Caps also have significant construction, repair and maintenance problems.”
Soil caps near Walkerville beneath the Mountain Con mine site and others have been difficult to seed. Often the plants die, exposing soil that is vulnerable to erosion.
Dewitt says the government hasn’t made a final decision on exactly how to deal with the soil at the Montana Pole site. Butte-Silver Bow will eventually take over ownership of the site, and the DEQ is beginning to work with the county to determine how the site will be used in the future.
A section of the plant will be ready for other use within about five years. Soil caps at least 12 inches deep are an option, but so is soil with a layer of asphalt.
“We don’t want to undermine the work that’s been done,” Dewitt said. “Butte-Silver Bow needs to figure out a use (for the property) that fits their needs and remains protective. We need to work together to build a comprehensive plan.”
But despite the progress made on the on-site soils, the groundwater contamination is extensive, and treatment will continue for at least 25 years.
Dewitt noted that 95 percent groundwater samples during the past 13 years either did not detect dioxin or exhibited concentrations of dioxin significantly below the ROD cleanup level.
It is a foregone conclusion that much of the Montana Pole and Treatment Plant site will not be fit for public use for many years, if ever. In Butte’s long history of environmental degradation, this is just another case that isn’t easily remedied.
“People are tired of places in Butte being declared off limits,” Ray said. “Essentially, they’re going to cap it and say stay away. They could have done better than that. I’m not so sure we should be happy with the end product.”
The DEQ said it's doing its best and is evaluating the project every five years as new technologies become available. The contamination plume has shrunk from 42 acres to 24 since treatment began, Dewitt said.
“The record of decision could be reopened if there is a protectiveness issue,” Dewitt said. “But the attorneys would make the final call. I would have real concerns if I felt we were leaving things that would eventually cause a problem.”