| Site Type: Long Term/National Priorities List (NPL) |
Map this site in Cleanups in My Community
| Augusta,  Maine|
| Kennebec County
| Street Address: ||EASTERN AVE, RT 17 |
| Zip Code: || 04330 |
| Congressional |
| EPA ID #: ||MED980731475 |
| Site ID #: ||0101031 |
| Site Aliases: |
| Site Responsibility: ||Federal, Potentially Responsible Parties |
| NPL LISTING HISTORY |
| Proposed Date ||12/30/1982|
| Final Date ||09/08/1983 |
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The O'Connor Company site occupies approximately twenty-three acres. The site is bordered by private properties and residences, woodlands, a small poultry farm, the west branch of Riggs Brook, and its associated wetlands. In the 1950s, the company began operating a salvage and electrical transformer recycling business at the site. Operations included stripping and recycling transformers containing polychlorinated biphenyl (PCB)-laden oil. In 1972, an oil spill at the site was found to have migrated towards Riggs Brook. Later that year, at the request of the State, the company began containing all transformer fluids found on the site in an aboveground storage tank to prevent future spills. When high levels of PCBs were detected in the soils during sampling by the State in 1976, the company was instructed to build two lagoons to control further migration of oils from the site. The upper lagoon, constructed with a concrete retaining wall and a discharge system, and a lower lagoon, constructed with a horizontal pipe discharge system and an earthen berm, were installed. In 1977 Maine DEP instructed the company to reclaim the lagoon areas. The company pumped water from the lagoons into several on-site storage tanks and excavated the lagoon sediments. These sediments were deposited into a low area and were covered by approximately 1 foot of clay soil. This created a barrier for natural surface water drainage from the site to Riggs Brook and resulted in the formation of a marsh behind the on-site barn. Approximately 50 people live within a 1/4-mile radius of the site. The nearest upgradient residence is approximately 300 feet west of the site. There are currently no downgradient residences as the land rises up east of Riggs Brook.
Threats and Contaminants
On-site groundwater is contaminated with polychlorinated biphenols (PCBs) and the volatile organic compounds (VOCs), dichlorobenzene and benzene. Prior to cleanup, site soil was contaminated with PCBs, lead, and various carcinogenic polycyclic aromatic hydrocarbons (cPAHs).
The site is being addressed in two stages: immediate actions and a long-term remedial phase focusing on cleanup of the entire site.
Response Action Status
|Immediate Actions ||In 1984, the O'Connor Company built a fence around the property and posted warning signs on approximately 5 acres of the site. The owner also sampled and analyzed the contents of all drums and storage tanks on the site and removed them. In 1987, Central Maine Power extended the fence to areas where additional contamination was found, and removed additional contaminated material from the site. |
|Entire Site ||EPA originally selected solvent extraction as the preferred remedy in 1989; however, extensive testing of site soils and the technology revealed that solvent extraction was not was not able to be implemented at this site. In the fall of 1995, the EPA selected a new remedy for the contaminated soils and sediments that allows for their excavation and off-site disposal without first undergoing treatment. The EPA selected the new remedy after five years of extensive testing of the solvent extraction treatment process. In 1996 and 1997, approximately 19,000 tons of contaminated soil and sediment were excavated and transported off site to licensed hazardous or special waste landfills. The site was restored by backfilling clean fill from off-site sources. In acknowledgement of the source control remedial action, the fence was removed in November 1997. Additionally, the potentially responsible parties established the wetlands to replace those lost during the cleanup. |
|Entire Site ||In 1996, EPA split the site into three operable units; source control (OU-1), management of migration (OU-2), and Riggs Brook (OU-3). For OU-2, the approach to groundwater remediation was changed following a reassessment in accordance with EPA guidance on PCBs and the technical practicability of restoring groundwater contaminated with PCB-contaminated oil within a reasonable timeframe. In Septemebr 2002, EPA issued a ROD amendment which changed the approach to groundwater remediation. The new approach includes institutional controls, a technical impracticability waiver of federal and state drinking water ARARs for a limited portion of the site, active recovery of separate-phase PCB oil, long-term monitoring, and five-year reviews. |
|OU-1, Source Control ||Remedial actions for OU-1 were substantially completed in 1997. EPA issued a Preliminary Close-Out Report in 1998 that documented that the performance standards for OU-1 had been met.|
In 2002, EPA and Maine DEP and Central Maine Power modified the source area boundary to simplify long-term maintenance. Maintenance continues under an approved Operation and Maintenance Plan that includes periodic soil sampling to confirm the integrity of the soil cover over the source area.
|OU-2, Management of Migration ||In 2002 EPA issued a Record of Decision Amendment that included a technical impracticability for a limited area of the Site. Long-term monitoring of the groundwater beyond the Technical Impracticability Zone has document that the performance standards set in the Record of Decision have been met. |
|OU-3, Riggs Brook ||For OU-3, sampling of Riggs Brook sediment and biota specified in the 1989 Record of Decision began in 1996 and 1997, respectively. The purpose of the sampling is to ensure that Riggs Brook remains protected after the removal of the contaminated soil. The latest data indicates that the PCB levels remain below the trigger level set in the 1989 ROD.|
In September 2007, EPA signed a Final Remedial Action Report for OU-3. This report documented that the cleanup performance standards selected in the ROD for Riggs Brook and all remedial actions related to Riggs Brook had been completed.
The results of the ten-year sampling program found the concentrations in the Riggs Brook to be stable with no indication that PCBs were migrating or increasing in concentrations. Over 95% of the samples were below the PCB action level of 5 ppm with the annual mean between 0.38 and 1.93 ppm. Additionally, the results of the biota sampling performed in 1997 and 2000 were consistently below the action level of 2 ppm.
|2007 Five-Year Review ||The 2007 five-year review concluded that the remedy for the entire site was protective of human health and the environment. Exposure pathways to contaminated soils are prevented by the soil cover and institutional controls. Similarly, exposure to contaminated groundwater within the TI Zone are prevented by institutional controls and groundwater performance standards are being met outside the TI Zone. Ten years of sampling for Riggs Brook also found the remedy to be protective of human health and the environment. |
|2012 Five-Year Review ||The 2012 five-year review concluded that the remedy for the entire site remained protective of human health and the environment. |
|2014 NPL Deletion ||Ongoing monitoring demonstrated that groundwater performance standards have been met outside the TI Zone for VOCs since 2002 and for PCBs since 2006. Therefore with the institutional controls in place to prevent access to the TI Zone, EPA, with Maine DEP concurrence, deleted the Site from the NPL. Final deletion occurred July 22, 2014. |
|Long-Term Monitoring ||Central Maine Power continues to monitor the Site to ensure that the soil cover installed in 1997 over the source area remains stable. Periodic sampling of the soil and groundwater will be performed to ensure that the remedy remains protective. |
|Enforcement Highlights||In 1984, EPA issued an Administrative Order to the O'Connor Company, requiring construction of a fence, posting of warning signs, and analysis of the contents of all drums and storage tanks found on the site. In 1986, EPA issued an Administrative Order to the company and Central Maine Power to conduct an investigation into the nature and extent of contamination at the site and to identify alternatives for site cleanup. In 1986, the State also issued Orders to the potentially responsible parties, requiring the removal of the hazardous substances present in tanks and containers at the site. In 1987, EPA and the State issued a joint Administrative Order to O'Connor and Central Maine Power to investigate the nature and extent of contamination, to identify alternatives for cleanup, and to extend the existing 5-acre fence to cover an additional 4 acres. In 1990, EPA and Central Maine Power signed a Consent Decree requiring the company to design and perform the cleanup.|
In 2004, following the Record of Decision Amendment, EPA, Maine DEP, and Cental Maine Power amended the 1990 Consent Decree to match the new remedy.
The posting of warning signs and the construction of a fence, which limits access to the contaminated areas of the site, and the removal of drums and storage tanks reduced the potential for exposure at the O'Connor Company site prior to the full cleanup in 1997. As a result of the 1996-1997 cleanup over 19,000 tons of contaminated soil and sediment were excavated and transported to appropriate disposal facilities. Sixty four (64) tons of barn debris was decontaminated, demolished and disposed of off site. Finally, 71,220 gallons of contaminated water were transported to off-site disposal and treatment facilities. Following the conclusion of the source control remediation, the fence was removed.
Current Site Status
In 1996 and 1997, approximately 1900 tons of soil was removed from the site. In September 2002 EPA amended the Record of Decision and approved a technical impracticability waiver for a limited portion of the site. The ongoing groundwater monitoring indicates that the groundwater beneath the rest of the site has met federal and state drinking water standards for VOCs since 2002 and for PCBs since 2006. With the site deleted from the NPL, monitoring will continue to ensure that the remedy remains protective.
Links to Other Site Information
Newsletters & Press Releases:
Federal Register Notices:
Reports and Studies:
|Administrative Record Index, OU 01 Record of Decision (ROD), September 27, 1989 (727 KB KB)   |
|Administrative Record Index, OU 01 Explanation of Significant Differences (ESD), July 11, 1994 (287 KB)   |
|Administrative Record Index, OU02 Record of Decision (ROD) Amendment, September 9, 2002 (228KB)   |
|Administrative Record Index, Combined Notice of Intent to Delete (NOID) and Notice of Deletion (NOD), March 13, 2014 (602 KB)   |
|Deletion Docket Index, Final Notice of Deletion (NOD), July 22, 2014 (559 KB)   |
|Administrative Record (AR) Index Addendum 2, Contingency Remedy, December 1, 1995, (531 KB)   |
Lithgow Public Library, Winthrop Street, Augusta, ME 04330
OSRR Records and Information Center, 1st Floor, 5 Post Office Square, Suite 100 (HSC), Boston, MA 02109-3912 (617) 918-1440
|EPA Remedial Project Manager: ||Terry Connelly |
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5 Post Office Sq., Suite 100
Mail Code OSRR07-1
Boston, MA 02109-3912
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|E-Mail Address: ||firstname.lastname@example.org |
|EPA Community Involvement Coordinator: ||Pamela Harting-Barrat |
|Address: ||US Environmental Protection Agency|
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Mail Code ORA20-1
Boston, MA 02109-3912
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