Pre-CERCLA Site Screening/ Abbreviated Preliminary Assessment
In August 2017, the department interviewed former employees and conducted a site visit. Following the Superfund site investigation process, the department completed a pre-CERCLA site screening and an abbreviated preliminary assessment, documenting the potential release of TCE into the environment. The Pre-CERCLA Site Screening and Abbreviated Preliminary Assessment reports recommended the site enter into the U.S. Environmental Protection Agency's active sites inventory, and additional investigation be performed.
Site Inspection
In 2019, a site inspection was completed, documenting the release of TCE into the environment. Drinking water, soil, sub-slab vapor, indoor and ambient air were assessed during the site inspection. The department collected samples from 17 private drinking water wells, one public drinking water well (Blair Heights Well) and two springs within 1 mile of the site. All samples were analyzed for VOCs, including TCE. No VOCs were detected in any water samples. The department collected a total of 14 sub-slab vapor, 13 indoor air and two ambient outdoor air samples. TCE was not detected in the outdoor air. TCE was detected in five sub-slab vapor samples and eight indoor air samples. The TCE concentrations in sub-slab vapor in one area of the building, closest to the loading dock, were elevated above sub-slab action levels. This data, along with TCE detection in the indoor air, indicates that some vapor intrusion is occurring in the building in Rooms 1, 2 and 3 near the loading dock. In the loading dock area on the northeast portion of the facility, the department collected a total of 23 soil samples from nine borings at depths ranging from zero to 17 feet. TCE was detected in 14 soil samples. The Site Inspection Report recommends additional site characterization to fully define the areas of TCE contamination.
Soil Sampling
In June 2020, the responsible parties conducted additional soil sampling according to the January 2020 approved supplemental soil investigation work plan. The goal of the work was to fully define the areas of TCE contamination. The supplemental soil investigation report confirmed the presence of chlorinated volatile organic compounds in soils. The detected levels of TCE are above screening levels considered protective of groundwater, additional investigation is required.
In 2021 and 2022, in response to the soil investigation report findings, the responsible parties conducted additional soil and groundwater sampling according to the June 2021 approved revised groundwater and soil investigation work plan. The responsible parties submitted a Groundwater and Soil Investigation Report to the department in June 2022, summarizing the results of this investigation. In 2023, an additional round of groundwater sampling was conducted at the site. The responsible parties submitted a letter report to the department in August 2023, summarizing the results of this groundwater sampling
Abatement Order on Consent
On July 16, 2024, Hamilton Sundstrand Corp. voluntarily entered into an Abatement Order on Consent with the department, which requires Hamilton to conduct additional investigation and, if necessary, remedial actions. The objectives of the order include determining the nature and extent of contamination by conducting a remedial investigation; determining and evaluating alternatives for remedial actions, if any, by conducting a feasibility study; recovering past and future response and oversight costs incurred by the department with respect to the order; and, if necessary, participating in good faith negotiations for a second Order or Consent Decree to implement the selected response action.
Indoor Air
In 2018, UTC conducted design work and pilot tested a sub-slab vapor mitigation system. The system installed consists of three independent blower motors that create negative pressure in the subsurface of Room 1 of the facility. Indoor air sampling was conducted after installing the system. Results from this sampling showed no detections of TCE in the facility. In February 2020, UTC conducted additional confirmatory indoor air sampling with department oversight. During this sampling event, the system was inspected and found to be in satisfactory condition. The sample results confirm that indoor air at the facility remains below levels of health concern. The sub-slab depressurization system is operating properly and vapor intrusion is not taking place. Continued operation and maintenance of the system is required. The responsible parties prepared an operation and maintenance plan for the sub-slab depressurization system, which the department approved April 26, 2021.
Remedial Investigation/ Feasibility Study
In response to the July 2024 Abatement Order on Consent, the responsible parties will conduct a remedial investigation and, if necessary, a feasibility study at the site. This stage involves evaluating the type and amount of waste released (nature of the contamination) and where the waste is located (extent of contamination) at a site and possible remedial actions, if needed.
