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Billings PCE Vapor Intrusion Systems

Site Contact:
Joe Payne
On-Scene Coordinator


Site Location:
Billings, MT 59101


The Billings PCE Site consists of a PCE (tetrachloroethylene) groundwater plume extending from 715 Central Avenue (presumed source area) east-northeast through a residential neighborhood and into downtown Billings. The source of the groundwater plume is likely the result of historic releases of PCE from a dry-cleaning operation. The groundwater plume reaches a width of 1,000 feet and length of 8,000 feet. The site is listed on the Superfund National Priorities List and currently undergoing Remedial Investigation/ Feasibility Study (RI/FS).

The Site is currently undergoing expansive sampling studies by the Superfund Remedial Program as part of the RI/FS. In Spring 2022 an indoor air study was done in many residential homes at the Site. Both indoor air samples and sub slab vapor intrusion air samples were taken. In some homes, sample results were found to be in exceedance of human health standards. The presence of PCE in home air samples indicates that the contaminated groundwater is releasing PCE vapors, which work their way upwards from the groundwater and into the residences.

The fall of 2022, the EPA Superfund Remedial Team asked the EPA Removal team to install sub slab depressurization systems to mitigate the vapor intrusion in several prioritized homes. This is a time critical removal action and work is planned to be completed during winter 2023.

EPA Removal Team completed installations at 9 prioritized residences during an operational period from March 5- March 16. The team then completed a follow-up sampling event in April.

The EPA Removal Team completed a second round of installations at 7 prioritized residences during an operational period from June 5- June 9, 2023. The team had a scheduling conflict with an 8th prioritized home which has been postponed until the fall.

A third mobilization was completed between November 1-9, 2023 for the remaining 11 prioritized properties in Billings.

In spring of 2024, EPA's Remedial team completed a follow up sampling event at the properties using the Trace Atmospheric Gas Analysis (TAGA) bus to ensure the efficacy of the systems. Additionally, one final installation was completed by the EPA Removal team.

The field work portion of this removal action is now complete.

If you have questions regarding PCE exposure, please contact the EPA and/or visit the Agency for Toxic Substances and Disease Registry (ATSDR) website here for further information and next steps:   https://www.atsdr.cdc.gov/sites/toxzine/tetrachloroethylene_toxzine.html  

For additional information, visit the Notices section.