State environmental regulators say a former wood treatment plant in Butte needs a new cleanup plan to make the toxic site safer for both people and groundwater.
South of where interstate I-90 slices through the Summit Valley in Butte is a sprawling 36 acre parcel of land that looks like harmless overgrown fields. But the state Department of Environmental Quality’s project manager Dave Bowers says this is actually ground zero for Butte’s smallest Superfund site - the Montana Pole and Treating Plant.
"Where the operation of the pole treating actually took place was through this area, it’s where the really severe contamination was," Bowers said.
The facility operated for almost 40 years, until 1984. During its run, it treated a lot of wood to prevent rot and decay. That work left behind a lot of toxic substances in the soil and groundwater. DEQ has been in charge of cleaning up the site for more than 20 years.
"We’re taking two of the contaminants and reducing the cleanup levels down to more protective cleanup levels," Bowers said.
DEQ officials say they need to change their cleanup plan because they’ve learned more about groundwater, and their old methods to degrade dioxins weren’t doing the job fast enough.
The state is proposing to make the cleanup levels for pentachlorophenol, which is a wood preservative - 17 times more stringent, to better protect groundwater - and levels about 7 times more stringent for dioxins, which are a highly toxic industrial byproduct.
More than 200,000 cubic yards of contaminated soils will be consolidated into a new capped and sealed 9 acre landfill on site.
"The plan all the way through was: dig it up, put it over here, treat it, and put it back," Bowers said.
The new cleanup standards will allow for industrial, commercial, and recreational use on the remaining 27 acres of land at the Pole Plant not occupied by the waste landfill.
"The only restriction we’re going to have on the area is there will be no residential development," Bowers said.
Butte-Silver Bow county is eyeing the location for a new animal shelter.
DEQ currently has about $28 million dollars left in the Superfund cashout settlement with former oil company Atlantic Richfield to clean up the area and do water treatment. Bowers says the proposed soil cleanup could cost in the neighborhood of $9 million, but it’s too soon to know for sure. He says the work to clean up the soil could be done this season.
David Hutchins is a scientist at Montana Tech who sees good things in the proposal, like the higher cleanup standards, but also a compromise around keeping more contaminated soil on site than was originally planned.
"It accomplishes the goal," Hutchins said. "It would have been preferable not to have the waste in place, I think, but we do what we can."
DEQ is holding a public meeting on the proposed changes to the Montana Pole Plant cleanup on Tuesday, February 18 from 6:30 to 8 pm at Butte Brewing Company. Public comments will be accepted through March 10.