What is the go-forward process from here?

The Feasibility Study (FS) was approved by EPA on June 17, 2021.

Next, EPA will issue a preliminary plan with its preferred options for site remediation. Residents and other stakeholders will have the opportunity to comment on the EPA’s preliminary plan and preferred option prior to the issuance of its Record of Decision (RoD), which will contain the final site remedy.

Ultimately, the EPA’s decision on the final clean-up plan will be based on the feasibility study, the remedial investigation and input from the community on their preliminary plan.

Do the residents of Columbia Falls have a say in future remedial decisions?

Residents and other stakeholders will have the opportunity to comment on EPA’s preliminary plan and preferred options prior to the EPA’s issuance of its Record of Decision (RoD), which will contain the final site remedy plan.

CFAC has closely involved the residents of Columbia Falls throughout the process. CFAC has regularly hosted meetings with the Community Liaison Panel, including representatives from EPA, MDEQ, CFAC and the Columbia Falls community.

CFAC believes it is vital that the public have access to information and a role in the decision-making process to address the site and is committed to working with the local community.

What is a slurry wall?

Slurry walls are subsurface barriers that impede or stop groundwater flow.

The subsurface wall would be designed to encompass the two landfills that are impacting groundwater. We anticipate it would be between 2 to 4 feet thick and between 100 to 125 feet deep, designed to encompass the LDU1 source area and prevent impacts to groundwater.

Slurry walls were a component of the selected remedies for 86 other Superfund sites. EPA and the National Research Council have both independently conducted studies to verify the effectiveness of slurry walls in achieving remedial action objectives.

Would a slurry wall be a long-term solution to remediate the site?

The Feasibility Study ranked a slurry wall highest among all options to effectively cut off the landfills from the groundwater. A slurry wall is a proven and effective tool for reducing impact quickly.

Eighty-six Superfund sites across the country have included a slurry wall in the selected remedy. Additionally, the slurry wall alternative would include monitoring wells both inside and outside the slurry wall to make sure it is working.

Should EPA choose this remediation option, CFAC anticipates a one to two-year construction period to complete.

How did the Feasibility Study rank the excavation option?

With approval from EPA, the excavation option was screened out of consideration because other options promised to achieve the same result faster and with fewer problems, especially less community disruption.

How long would the excavation option take?

The expected timeframe for completion of excavation and removal would be approximately 4 to 5 years, assuming the removal of approximately 70 truckloads of excavated material per day, seven days a week, 8 months a year.

What kind of impact would excavation work have on the community?

Residents in Aluminum City and along the Route 406 truck route, including the Head Start and Gateway Glacier Elementary School, would likely be subject to trucks regularly passing through their neighborhoods for several years. It could be as many as 70 trucks per day.

Communities along the train tracks also would experience increased train traffic and disruption from increased grade crossings in the event of transport by train.

The impact to quality of life for the residents of these communities as well as to visitors to Glacier National Park due to this increased traffic would include noise, dust, and congestion (truck traffic or delays from railroad crossings) above and beyond the significant seasonal increases.

Would digging up the landfills and transporting the material off-site clean up the groundwater faster?

No. A slurry wall can be installed in one to two years and stop almost all of the groundwater impact immediately.

In contrast, digging up the material will take at least four to five years and the groundwater quality could worsen during that time because of the potential for contamination during the excavation process.

Is there a solution that involves minimal community disruption?

Yes, a slurry wall. All of the work would be done on site, with no trucks or trains hauling waste through the community.

How will you know whether the remedial action is working?

Once an alternative is selected and implemented, the Superfund process requires EPA to perform a comprehensive review every five years to ensure the implemented remedy continues to protect human health and the environment and complies with all applicable laws.

The slurry wall alternative would include wells both inside and outside the slurry wall that would be monitored regularly to make sure it is working.

What will happen to the site after the clean-up process is complete?

The Superfund site encompasses approximately 1,300 acres, most of which were used during the operating period.

CFAC is remediating this area for the purpose of future industrial or commercial use.