From 1946 until 1984, the Montana Pole and Treating Plant operated in Butte, using a toxic mix of chemicals to treat wood for industrial uses and releasing those chemicals onto the land without controls, according to the Montana Department of Environmental Quality.
In 1983, a year before the plant closed, DEQ responded to reports of an oily substance seeping into Silver Bow Creek and found PCP, petroleum and dioxin contamination in Silver Bow Creek and in surrounding soil and groundwater. The discovery led the Environmental Protection Agency to conduct an emergency cleanup of the site, which lies north of Greenwood Avenue and south of Silver Bow Creek and is bisected by Interstate 15-90, in 1985.
As part of that initial cleanup, the EPA installed a water-treatment system, excavated some 6,000 cubic yards of soil, stored the soil in the plant’s old pole barns and added fencing around contaminated areas of the site to keep people out.
Over the next eight years, preliminary work to remediate the site continued. Meanwhile the federal government sued the responsible parties to recover the money required to clean-up the site and the EPA and DEQ worked with stakeholders to come up with a Record of Decision, a formal agreement that described the objectives of the Superfund site cleanup and the plan for achieving those objectives.
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Released in 1993, the Record of Decision created a plan for how to deal with the contaminated soil. The plan was relatively simple. DEQ would move contaminated soil from containment units in the site’s pole barns to an adjacent land treatment unit, where soil would be tilled, watered and exposed to air. According to scientific evidence available at the time, this would remediate the level of PCP, dioxin and contamination in the soil to acceptable levels. Once it met offload requirements for acceptable levels of contaminants, the soil would then be moved back onto the land and a new “batch” of contaminated soil would be moved to the land treatment unit. The plan also involved treating groundwater a water treatment facility that opened in 1993 on the part of the site that lies north of the interstate.
The 1993 Record of Decision also set a variety remedial goals that this process would achieve. Those goals included ensuring that the soil and sediment “contaminant concentration levels pose no unacceptable risk to human health or the environment” and that the groundwater cleanup levels “be protective of human health and the environment and will ensure that uncontaminated aquifers and adjacent surface waters are protected for potential beneficial uses.”
A crucial element of the Record of Decision involved the cleanup level it set.
As David Bowers, environmental scientists with the Department of Environmental Quality explained at Tuesday’s meeting, Superfund sites can be cleaned up to any of three levels: the residential level, which is the most stringent, because residents would be exposed to remaining contaminants almost constantly; the industrial level, which is less stringent, because the site must be safe for workers exposed to the remaining contaminants for 40 hours a week, with two weeks off a year; or the recreational level, which is the least stringent, because people will only use the land occasionally and therefore can be exposed to higher levels of contamination for less time.
Bowers said the Record of Decision selected the least-stringent recreational level for remediation at the Montana Pole and Treatment Site.
The document itself, however, is somewhat more ambiguous.
According to the 1993 Record of Decision, “Soil cleanup levels have been developed to protect recreational and industrial land users at the site from excessive health risks.” Elsewhere in the document, however, it states that “soils (sic) cleanup levels established in this Record of Decision are health based standards for recreational use of the Site that do not provide for unlimited use with unrestricted exposure ….” And another passage in the document notes that “the cleanup levels established will be protective for industrial use at the site ….”
In a follow-up interview, Bowers acknowledged the differing language in the Record of Decision but noted that changes in DEQ’s standards for the different cleanup levels mean that the remediation levels called for in the report no longer meet the standard for industrial use.
“What we’re trying to do is create the bright line that wasn’t there before,” Bowers said, “and we see that bright line as the recreational level.”