Information Summary for Square D Site in Buncombe County
Site History
According to property records from the Buncombe County Tax Office, the property was purchased by Gorham Manufacturing Company in 1952 and subsequently sold to Square D Company in 1960. Both companies operated a manufacturing business at the site. Over time, Square D's operations expanded into other buildings and parcels in the immediate area of 128 Bingham Road. In 1991, Schneider Electric acquired the Square D Company. Square D/Schneider Electric later broke up its property on Bingham Road and sold a portion to the Buncombe County Board of Education in 1989. The parcel at 128 Bingham Rd was purchased by ASC Business Park, LLC in 2005.
Groundwater contamination at the Square D Site was identified, listed and regulated by the Division of Water Quality's – Aquifer Protection Section (APS) in 1990 under their incident number 5394. Under the regulatory jurisdiction of the APS, the site underwent assessment to define the extent of soil and groundwater contamination. Remedial (cleanup) actions, including pumping and treating groundwater to reduce contaminant concentrations, have been ongoing since 1994. Groundwater monitoring has also been conducted regularly since the early 1990s. City water is provided to the area.
In 2007-2008, a reorganization occurred within the North Carolina Department of Environment and Natural Resources, which transferred regulatory oversight of the Square D site to the Division of Waste Management's Inactive Hazardous Sites Branch. Based on file information which indicated that there were no drinking water impacts or direct contact issues, the IHSB sent correspondence to Schneider Electric/Square D on March 18, 2008 requesting that they continue with assessment and remediation in the IHSB's privatized remediation program or Registered Environmental Consultant (REC) program.
Recent review of the site information resulted in DENR sending a Request for Additional Investigation to Schneider Electric/Square D on March 30, 2012, requesting that they conduct additional groundwater assessment and an evaluation of any potential for vapors from remaining contaminants in the groundwater to migrate into nearby occupied buildings.
Vapor intrusion is a relatively new and rapidly evolving issue used in the examination of contamination sites. A vapor intrusion study is a step-wise evaluation to determine if groundwater contamination is impacting indoor air quality levels at a level of concern for the chemicals involved. The evaluations typically first determine if soil gas concentrations immediately adjacent to the building are high enough to represent a potential concern to the indoor air quality of a structure.
If the soil gas concentration exceeds screening limits, the study then moves forward to test sub-slab and/or indoor air concentrations of target contaminants. There are many potential sources of contamination which can affect indoor air quality, including cleaners, carpets, paint and other items common in buildings. The indoor air portion of the study, if needed, helps determine if contaminants are entering the building and if so, what contaminants are entering the building from underground versus contaminants from building sources, and if the concentrations are safe.
A similar study has been conducted at the Buncombe County Board of Education Building, with the first step being to determine if groundwater contamination exists close enough to the building to warrant further vapor intrusion study.
At DENR's direction, Square D's contractor/consultant sampled monitoring well MW20D on Wednesday, August 8, 2012. The Buncombe County Board of Education hired a contractor/consultant to split samples the same day. The final laboratory results from Square D's samples were received by DENR on August 22, 2012, and none of the tested chemicals were detected. DENR has directed Square D to install an additional monitoring well to further delineate the extent of groundwater contamination.
- Tables summarizing monitoring wells across time up to May 2012
- Results from May 2012 Groundwater Sampling Event (Monitoring Well MW 20 D results are included separately, below)
- Square D August 8, 2012 Sampling Results from Monitoring Well 20D (Buncombe County Board of Education privately conducted separate sampling events of Monitoring Well 20 D on August 8 and 14. Those results are available through Buncombe County Board of Education.)
New monitoring well to be drilled
The IHSB requested that Square D resample monitoring well nest MW-15. Monitoring well nest MW-15 includes a shallow well (MW-15 at 86.9 feet deep), a deeper well (MW-15Ds at 115 feet deep) and a deep bedrock monitoring well (MW-15Dd at 166.3 feet deep).
The MW-15 well nest had not been sampled in several years (see data excerpt from previous site monitoring reports) and had previously shown concentrations of the primary site pollutants; tetrachloroethylene (PCE) and trichlorotheylene (TCE) and minor concentrations of degradation daughter chemicals. As part of IHSB's evaluation of the site for potential vapor intrusion concerns, Square D was directed to resample several additional monitoring wells, including the MW-15 nest, as part of the their periodic monitoring event schedule. The MW-15 well nest was sampled 5/30/12 and 5/31/12 (see data excerpt below). The IHSB also requested that another deep monitoring well (MW-20D at 195 feet deep) be sampled due to its closer proximity to the Buncombe Co Board of Education building than MW-15Dd. MW-20D had previously been paved over and had to be relocated before it was resampled on 8/8/12 (the sample concentrations were non-detect).
| Location | Date | PCE Concentration (ppb) | TCE Concentration (ppb) |
|---|---|---|---|
| MW-15 | 8/25/94 | 9.1 | 4.2 |
| MW-15 | 9/1/94 | <9.1 | 110 |
| MW-15 | 5/21/97 | 97 | 1100 |
| MW-15 | 5/16/01 | 88 | 650 |
| MW-15 | 5/30/12 | 123 | 287 |
| MW-15Ds | 8/31/94 | 36 | 190 |
| MW-15Ds | 9/1/94 | 62 | 240 |
| MW-15Ds | 5/31/12 | 6.6 | 9 |
| MW-15Dd | 9/1/94 | 28 | 110 |
| MW-15Dd | 12/9/97 | 57 | 120 |
| MW-15Dd | 5/31/12 | 72.7 | 73.1 |
Although MW-20D's sample results were non-detect for the constituents of concern, due to the increase in constituent concentrations detected at shallow monitoring well MW-15 during the 5/30/12 sampling event, IHSB requested that another monitoring well be installed within 100 feet of the Buncombe Co Board of Education building as part of the ongoing efforts to determine if groundwater contamination exists close enough to the building to justify further study of potential vapor intrusion concerns in soil gas next to the building. The work plan detailing the additional monitoring well location, as well as plans to conduct soil gas testing at an industrial building at 128 Bingham Rd, was received by the IHSB on 8/20/12. The document is entitled "Groundwater and Soil Gas Sampling Work Plan" and it was loaded onto the Division's electronic data management system.
How to access all files on this site, contact information for file review
Both the former DWQ-APS files and the IHSB's files regarding the regulatory history of this site, assessment and remedial actions, are available for public review in the Mooresville Regional Office.
To schedule a time to review the entire contents of site-related files (total files for this site encompass approximately four file boxes), please call Donna DeCarlo at (704) 235-2166, or email donna.decarlo@ncdenr.gov .