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Billings PCE Vapor Intrusion Systems

Notices  Posted Category
Site Description 3/22/2023 00 Background

The Billings PCE Site consists of an 860-acre contaminant shallow groundwater plume that extends from 715 Central Avenue (the presumed primary source area) approximately three miles east-northeast through residential, commercial, and school buildings and into downtown Billings, Montana. The contaminated groundwater plume contains chlorinated solvents, mainly PCE, from historic area dry cleaning businesses. The site is listed on the National Priorities List and is currently undergoing remedial
investigation/feasibility study (RI/FS).

The Site is undergoing expansive sampling studies by the Superfund Remedial Program as part of the RI/FS. In Spring 2022, an indoor air study was completed in several residential homes located within the Site. Both indoor air samples and sub-slab vapor intrusion air samples were collected. Sample results were found to be in exceedance of human health standards in multiple homes when compared against EPA’s Indoor Air Vapor Intrusion Screening Levels (IA VI SLs), Indoor Air Vapor Intrusion Removal
Management Levels (IA VI RMLs), and Sub-Slab Vapor Action Levels (SSALs). Based on the sampling results, EPA has determined that at least nine of these homes require immediate prioritization for the installation of vapor mitigation systems. Sampling results are provided in the toxicology report found in the documents section of this website.
Safety Message 3/22/2023 00 Background
EPA personnel and contractors will be primarily cautious with slips, trips and falls during cold weather events in the area. Because the team will be entering residential properties, they will also be cognizant and respectful of pets and personal property onsite.
Site Objectives 3/22/2023 00 Background

The objective of this removal action is to reduce the exposure level of PCE and it's daughter products in residential homes.



Period Objectives 3/22/2023 01 March 05- 16

1. Mobilize equipment and personnel.

2. Install vapor mitigation sub-slab depressurization systems in the 9 prioritized homes.

3. Demobilize equipment and personnel.
Activities Accomplished 3/22/2023 01 March 05- 16

The EPA removal team (EPA personnel, EPA contractors) completed the installation in homes and saw vacuum pressure present in each of the nine prioritized homes. Installations began on Tuesday, March 7 and were completed on Wednesday, March 15. The team was able to install each system over the course of a day and in one case, two in one day. Only one installation required further configuration and additional visits to the home. 

Homeowners were very accommodating in their schedules to help the team work efficiently. The team worked through the entire operational period with only a rest on Sunday.
Planned Activities 3/22/2023 01 March 05- 16
The EPA removal team (EPA personnel, EPA Contractors) plans to return to the 9 homes where installations were completed in Spring 2023 to do a post-installation sampling event. This will provide all parties with before and after installation exposure data and show the efficacy of the sub-slab depressurization systems.
Period Objectives 6/15/2023 02 June 04-9

1. Mobilize equipment and personnel.

2. Install vapor mitigation sub-slab depressurization systems in the 8 prioritized homes.

3. Demobilize equipment and personnel.
Activities Accomplished 6/15/2023 02 June 04-9

The EPA removal team (EPA personnel, EPA contractors) completed the installation in 7 of the 8 homes and saw vacuum pressure present in each. Installations began on Monday, June 5 and were completed on Friday, June 9. The team was able to install each system over the course of a day and in a few cases, two in one day. One installation required further configuration and additional visits to the property. 

Homeowners were very accommodating in their schedules to help the team work efficiently. Only one property experienced scheduling conflicts, the installation at this property has been postponed until the next mobilization in the fall.
Planned Activities 6/15/2023 02 June 04-9

The EPA removal team (EPA personnel, EPA Contractors) plans to return to the 7 homes where installations were completed in Spring 2023 to do a post-installation sampling event this coming winter. This will provide all parties with before and after installation exposure data and show the efficacy of the sub-slab depressurization systems.

 

The EPA removal team also plans to mobilize again this fall to complete another round of prioritized installations, including the one property that was postponed due to scheduling conflicts.
Period Objectives 11/8/2023 03 November 1-12

1. Mobilize equipment and personnel.

2. Install vapor mitigation sub-slab depressurization systems in the 11 prioritized properties.

3. Demobilize equipment and personnel.
Activities Accomplished 11/9/2023 03 November 1-12

The EPA removal team (EPA personnel, EPA contractors) completed the installation of the remaining 11 properties identified as tier 1 priorities by the EPA Remedial Team. Installations began on Thursday, November 2 and were completed Thursday November 9. The team was able to install each system over the course of a day and in a few cases, two in one day.

Homeowners were very accommodating in their schedules to help the team work efficiently.



Planned Activities 11/9/2023 03 November 1-12
Pending a sampling event in the coming months to confirm the efficacy of the systems, this concludes the field work for removal action at Billings PCE Vapor Intrusion Systems. EPA's Remedial team will continue work in the area and help remediate the contamination, this may include the installation of further vapor mitigation systems at properties that did not warrant urgent action from the Removal Team but still qualify for a system.  For further information on the site and the Remedial Team's activities, please see https://cumulis.epa.gov/supercpad/cursites/csitinfo.cfm?id=0801303