New Hanover County Airport Burn Pit

• Site Profile
• Administrative Record Index (All PDF): OU1 (11 pp., 451K), ROD Amend (2 pp., 63K)
• 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:
The New Hanover Site is located in Wilmington, New Hanover County, North Carolina. The 1,500 square foot burn pit was located near the center of a 4-acre plot. Land use in the vicinity of the Site is commercial, industrial, and residential. Approximately 500 people live near the site. The Site was originally developed as a military hospital during World War II.

The construction date of the original burn pit is unknown, but a second pit was constructed in 1968 and used until 1979 for firefighter training purposes. Jet fuel, gasoline, petroleum storage tank bottoms, fuel oil, kerosene, and sorbent materials from oil spill cleanups were burned in the pit. It is estimated that between 100 to 500 gallons of ignitable fuel were used during each firefighting training exercise. Water was the primary fire extinguishing agent; however, carbon dioxide and dry chemicals were also used.

In 1985, sampling by the County showed heavy metals and volatile organic compounds in the pit sludge. In May 1986, the State confirmed the presence of contamination. The potentially responsible parties (PRPs) were provided the opportunity to conduct the remedial investigation and feasibility study (RI/FS), however, the Agency found their good faith offer to be deficient. Therefore, the moratorium was not extended and the Agency initiated Fund monies to conduct the RI/FS. However, the PRPs did conduct a removal action at the Site in 1990 under an Administrative Order on Consent.

Contaminants detected in the soils include benzene, ethylbenzene, total xylene, 2-methylnaphthalene, phenanthrene, and chromium. Contaminants detected in the groundwater above Federal Maximum Contaminant Levels (MCLs) and/or State groundwater quality standards included benzene, chloroform, 1,2-dichloroethane, and ethylbenzene. The total volume of groundwater impacted by the Site is estimated to be 9.7 million gallons. The plume of contamination has remained on-site. The health risk posed by this site is primarily from the future use of the groundwater as a potable source due to the presence of contaminants at concentrations above EPA's MCLs for drinking water and the State of North Carolina groundwater quality standards.

Cleanup Progress: Threat Mitigated by Physical Cleanup Work
A Record of Decision was issued for this Site in September 1992. Subsequently, the PRPs submitted a work plan to conduct a treatability study on air sparging technology. In 1999 the PRPs completed collecting additional groundwater data to confirm that elevated levels of chromium do not exist at the Site. In late 1999 EPA proposed modifying the groundwater remediation approach as specified in the Record of Decision. EPA amended the ROD to include air sparging as the new selected remedy on April 11, 2000. The PRPs installed additional wells and resample the monitoring wells to better delineate the site. EPA approved the PRPs final Remedial Design Report.  In January 2008, a Five-Year Review was tasked to the U.S. Army Corps of Engineers (USACE).  The USACE will conduct site inspections and assess the protectiveness of the remedy at the New Hanover County Site.   The Five-Year Review Report was signed on August 26, 2008.  The report documents that the selected remedy is protective of human health and the environment.  As of June 2009, the groundwater system is currently pumping at its optimum.  Monitoring will continue under the approved groundwater monitoring program.