Mallory Capacitor Company

• Site Profile
• Administrative Record Index: OU1 (8 pp., 410K)
• Additional Site Documents including Five Year Reviews, Records of Decisions (ROD) and Explanation of Significant Differences (ESD).
• For documents not available on the website, please contact the Region 4 Freedom of Information Office (http://www.epa.gov/region4/foiapgs/submit.htm).

Site Background:
Electrical capacitors were manufactured on the 8.5 acre Mallory Capacitor site from 1969 to 1984. The operators first used polychlorinated biphenyls (PCBs) as the dielectric fluid in the capacitors, switching to a plastics chemical in 1978. The factory changed ownership when Dart Industries purchased it in 1979. Dart later sold the property in 1980 to Emhart Industries, Inc. As part of the sales agreement with Emhart, certain PCB wastes, a buried tank, and PCB contaminated soil were removed from the site and sent to an approved PCB disposal facility. The plant continued to operate, but voluntarily closed in 1984 when PCBs were discovered throughout the site. The EPA found that PCBs entered the environment through spills, leaks, and intentional discharges. The plant is located in a small community. Approximately 900 people obtain drinking water from wells and springs within 3 miles of the site. The site is in the flood plain of the Green River. Surface water located within 3 miles of the site is used for fishing and swimming.

PCBs and volatile organic compounds (VOCs) have been detected in groundwater. Off-site wells are contaminated with PCBs and volatile organic compounds (VOCs) such as trichloroethylene (TCE) and dichloroethylene. Coming into contact with or accidentally ingesting contaminated groundwater could pose a human health threat. The presence of PCBs and VOCs poses a threat to the environment, as they are toxic to aquatic wildlife.

Cleanup Progress: Construction Completed
From 1988 to 1989, under an Administrative Order with the EPA, a potentially responsible party removed approximately 20,100 tons of PCB-contaminated soil and 3,400 cubic yards of plant debris and sent them to an EPA-approved disposal facility. Contaminated soils were excavated all the way to bedrock. This completed the soil removal. In 1989, the potentially responsible parties, working with the EPA under an Administrative Order, completed an investigation into the nature and extent of PCB and VOC site contamination.  This included installation of numerous monitoring wells on and off site, assessment of the possible toxicological effects of the contamination, and identification of possible cleanup alternatives (remedies). In September 1991, the EPA issued the Record of Decision (ROD) and selected a remedy which involved on- and off-site hydraulic containment of the contaminated groundwater plume with extraction and treatment. In 1993, design of the groundwater treatment system was completed. Groundwater extraction and treatment activities began in November 1993.  Fractured bedrock in this area, along with possible influence of karst features (caves, springs, etc.) and non-aqueous phase liquid contaminants, has made for complicated optimization of the ground water extraction system. The operation, maintenance, and monitoring activities required by the EPA were begun, have continued and are ongoing to this day.  Activities include groundwater and sediment monitoring and periodic reporting to EPA in accordance with the Phase II Operation Maintenance, and Monitoring Plan for the site. Ongoing optimization has become an iterative process to ensure that no additional off-site contaminant migration takes place and significant contaminant removal continues. In February /March 2001, EPA approved the installation of six additional monitoring wells at the site to better characterize and monitor the extent and clean-up of the groundwater contamination. EPA also requested an updated private well survey for the site. Installation and sampling of the wells was completed in October 2001. Results of the sampling and the private well survey are documented in the 2002 Annual Report.

A second mandatory Five-Year Review (FYR) of the remedial action at the site was begun in Summer 2002 and completed by Summer 2003. Potential groundwater recovery enhancement technologies that may be applicable at the Mallory Capacitor site were reviewed. This was done in order to determine if new technologies developed in the last 10 years for groundwater recovery and clean-up could enhance contaminant recovery and accelerate the long-term completion of groundwater remediation at the site. The FYR concluded the remedy at the Mallory Capacitor site continues to protect human health and the environment. The groundwater extraction and treatment system continues to remain functional and well maintained. Contaminant mass removal has continued to increase over time and continues to provide effective source control and functions as an effective contaminant mass removal system. Enhanced recovery technologies are not required at this time and could potentially jeopardize the effective source control and effective contaminant mass removal of the currently optimized groundwater extraction and treatment system.

In June 2004, an on site vapor intrusion pathway assessment was begun because volatile organic compound (VOC) concentrations beneath the site exceeded groundwater screening levels presented in the US EPA’s 2002 Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from the Groundwater and Soils. The assessment developed and utilized site-specific screening levels based on actual soil conditions that are representative of the study area.  The assessment concluded on-site soil gas where VOC concentrations in shallow bedrock groundwater are highest, do not pose human health risks above acceptable levels through indoor air inhalation.  It should be noted that the VOC concentrations in off-site shallow bedrock groundwater are significantly lower when compared to levels on-site where the soil gas study was conducted.  Likewise, VOC concentrations in off-site soil gas would be significantly lower. Therefore, off-site soil gas quality conditions should not pose adverse human health risks.

In November 2007, EPA initiated the third mandatory Five-Year Review (FYR). This FYR was completed in June 2008 and concluded the following.  The groundwater extraction and treatment system continues to remain functional and well maintained.  The system continues to provide effective source control and functions as an effective contaminant mass removal system.  A protectiveness determination of the remedy at the Mallory Capacitor Company Site cannot be made at this time until further information is obtained.  In support of this Five‑Year Review, U. S. EPA reviewed the human health risk assessment (HHRA) that was previously conducted for the Site in 1991.  The review determined further information needs to be obtained by taking the following actions:

• the 2002 private water well search needs to be updated to assure no potable water wells or drinking water sources exist within and immediately down gradient from the groundwater plume emanating from the Site;
• determine whether a fish consumption exposure pathway from the Green River currently exists;
• apply current statistical methods to confirm exposure point concentrations (EPCs) for PCBs in on‑Site subsurface soils are protective of on‑Site construction workers using confirmatory sampling data collected following the 1988/1989 soil remediation.

It is expected that these actions will take no more than one year to complete. When these actions are complete a protectiveness determination will be made.  It should be noted that the drinking water Maximum Contaminant Levels (MCLs) for Polychlorinated Biphenyl (PCBs), Trichloroethene (TCE), cis‑1,2‑dichloroethene (cis‑1,2‑DCE), and trans‑1,2‑dichloroethene (trans‑1,2‑DCE) have not changed since 1991 and are still protective from a health risk perspective.  The Five-Year Review Report was approved on June 27, 2008.

Based on information obtained during the Five Year Review, the protectiveness determination of the remedy at the Mallory Capacitor Company Site was deferred for one year until the following information could be obtained:

• An update to the 2002 private water well search assuring no potable water wells or drinking water sources exist within and immediately down gradient from the groundwater plume emanating from the Site;
• Determine whether a fish consumption exposure pathway from the Green River currently exists;
• Apply current statistical methods to confirm exposure point concentrations (EPCs) for PCBs in on‑Site subsurface soils are protective of on‑Site construction workers using confirmatory sampling data collected following the 1988/1989 soil remediation.

The protectiveness statement was updated as part of the Five Year Review Addendum on June 24th, 2009.

The remedy at the Mallory Capacitor Site currently protects human health and the environment in the short term.

• The results of the previous water well searches have been confirmed; no potable water wells were identified down-gradient from the Site.
• The Green River adjacent to the Site does not support a significant fish population for consumption, since it is shallow, relatively fast-flowing, and the river bed consists of either exposed bedrock or bedrock covered by gravel/small stones, and there are no quiescent pools of deep water. Additionally, interviews conducted in March 2009 a Wayne County TWRA Officer, stated the nearest location for edible fish habitat is approximately 5,000 feet downstream from the Site.
• The results from the HHRA indicate the potential risk and hazard to a construction worker from exposure to PCBs in Site soil are within acceptable levels. The evaluation for the construction worker presented in the HHRA was conservative compared with current methodologies and the conclusions regarding the construction worker scenario are still valid.

  All exposure pathways that could result in unacceptable risks at the Site are currently under control. However, in order for the remedy to be protective in the long-term, the following actions need to be taken:

  • Institutional controls need to be implemented at the Site. A Notice of Land Use Restriction is currently being negotiated for the Site.
  • Long-term protectiveness of the remedial action will be verified by obtaining additional groundwater samples to fully evaluate potential migration of the contaminant plume down-gradient from the treatment area and towards the river. Quarterly groundwater sampling and analysis will continue at the Site. Current monitoring data indicate the remedy is functioning as required to achieve groundwater cleanup goals.