BILLINGS — EPA crews are testing the air inside buildings across Billings, searching for traces of chemicals that are invisible to the naked eye — PCE and TCE.
The crews pulled air straight out of the KTVQ newsroom, looking for chemicals we can't see. The contamination below Billings isn't in question.
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The Environmental Protection Agency (EPA) had been doing some mitigation, digging 3,600 tons of dirt at the source of the contamination at 715 Central Ave., a former dry cleaner site, about two decades ago.
What the EPA is trying to determine is whether that contamination is making its way into buildings above it, and if so, at what level.
"Those chlorinated solvents can vaporize and through preferential pathways," Jo Machesky with the EPA said.
KTVQ isn't the only building being tested. At Dahl Funeral Chapel, Richard Hall said they were surprised to learn the contamination reached their property. In fact, there are hundreds of private and commercial properties being tested.
"We are sort of on the edge of it, but surprised that we were still contained," Hall said.
The news initially brought concerns about what could be in the air.
"The more that we looked into it and the more that we spoke with the EPA, it seems like the indoor air quality does not seem to be as much of a concern as it is the ground level, underground possibility," Hall said.
Machesky said crews are moving through buildings, testing the air in real time to determine whether those chemicals could be coming from below.
"As we move through the building, we're looking in real time to see if there's any elevated concentration that we might be able to tie to vapor intrusion and differentiate those from potential impacts with the tumor products," Machesky said.
In other words, finding the chemical doesn't necessarily mean they've found a health threat. This equipment can detect PCE and TCE at levels far below EPA health benchmarks.
But because these chemicals can move from contaminated groundwater into buildings, the EPA isn't just looking for an immediate danger. It's looking at whether people could be exposed over years.
"They're known to cause adverse health impacts at high concentrations. And this is not acute. These are low levels that would be kind of health impacts over a long time here. So they (took a) really long time for a residential building," Machesky said.
For Hall, getting answers from the EPA has eased some of those initial concerns.
"Only after speaking with the EPA and looking more into it, we're not too concerned about it. We definitely did want to get the building tested," Hall said.
That's why the EPA is testing buildings one by one, trying to separate the presence of these chemicals from levels that could actually pose a health concern. Stephen Blaze said the equipment can detect PCE and TCE well before concentrations reach health-based benchmarks.
"Our detection limits are incredibly low, in the part per trillion levels, which allows us to analyze at levels below health risk numbers," Blaze said.
And where the EPA determines vapors need to be controlled, crews can keep them from entering a building in the first place.
"Depending on where the building is located within the site, they might be automatically eligible for a mitigation system, which could be something like a sub-cloud vapor extraction system, very similar to a radon mitigation system," Machesky said.
"EPA has technology that can easily remediate the issues," Blaze said.
Related:
Billings PCE Superfund site cleanup enters next phase of mitigation
EPA makes Billings site a priority on Superfund list
