The dozens of employees that worked for years in hazmat suits and gas masks to remove toxic amphibole asbestos dust from residences in Libby and Troy have finished their cleanup duties, but that doesn’t mean the arduous task of decontaminating the entire Libby Asbestos Superfund Site is done.

“Cleaning homes was one of the largest tasks for sure, but there are other areas that still need our attention. I’ll be here for those,” said Mike Cirian, the U.S. Environmental Protection Agency project manager of the site.

The decontamination of thousands of homes — a process many in Lincoln County saw as a necessary annoyance — was no small feat. But the homes only accounted for two of the site’s eight “operable units,” which are specific tasks or geographic areas where cleanup action is required in order to prepare those areas for any future use.

In Libby’s case, the units are places where research and investigation determined high levels of asbestos dust had settled as a result longtime operations at the W.R. Grace & Co. vermiculite mine. Each unit is required to go through a complex cleaning process set forth by the EPA that typically includes nine phases. The first step is a preliminary assessment and site investigation that includes a review of historical information of that area, a visit to the unit itself to evaluate the potential for a release of hazardous substances, and more. The final stage is site reuse and redevelopment in which the EPA works closely with communities to make sure sites or portions of sites are used safely.

“Along the way, we have a lot of hands and eyes on the whole process,” Cirian said. “There are a lot of people involved in approving each step and holding us accountable.”

Aside from the residential portion, which account for units four and seven collectively, the other six operable units at the Libby Asbestos Superfund Site include the former export plant, the screening plant, the old Stimson Lumber Mill, the Libby railroad area owned and operated by BNSF Railway Co., certain highway transportation corridors including 30 miles of U.S. 2, and the mine itself and surrounding forested area.

It’s the latter unit, the mine from which the asbestos came and surrounding forest lands, that still remain in planning limbo. Cirian said the task is unfamiliar territory for the EPA because, how does one go about cleaning toxic asbestos from an entire mining site and forest?

That’s the looming question a team is hoping to answer in the coming months while working closely with Grace, which still owns the mine, the U.S. Forest Service and other stakeholders.

“Right now we can’t say for certain what cleanup over there is going to look like,” Cirian said. “We don’t want to prejudge the remedy.”

Currently, the federal agency is evaluating several treatment technologies that could be implemented to reduce exposures to asbestos in soil, water, sediment, mine waste and other materials. There are a wide array of possibilities, but Cirian said it will take some time before a viable cleaning solution is reached.

“We really don’t have a clear idea yet. It could be anything from just monitoring the site closely to digging everything up and moving it somewhere else. Most likely the answer will be in the middle of those,” Cirian said.

As for the other units, significant progress has been made over the years.

In April this year, a portion of the area associated with the screening plant was removed for the National Priorities List. The moment was a major milestone for Libby as the area has now entered the reuse phase — the final goal for every EPA Superfund project.

At the Stimson Lumber property, railroad area, highway corridors and export plant, operation and maintenance activities are ongoing. That means demanding steps such as remedial investigations and actions that can often last for years have been completed and the EPA is working with other entities such as the Montana Department of Environmental Quality to assure the site is properly maintained.

“It’s taken 20 years to get to this point and it’s time to finish strong,” Cirian said.

Reporter Kianna Gardner can be reached at 758-4439 or kgardner@dailyinterlake.com