The Department of Natural Resources and Environmental Control's (DNREC’s) Tank Management Branch, with assistance from the Department of Health and Social Services - Division of Public Health, held a public workshop Oct. 27, 2009 to discuss the results of environmental testing of homes on Hillside Road in Claymont.
The workshop provided an update for Claymont residents on recent tests conducted on the indoor air quality in four homes and soil gas levels around the foundations of seven homes along Hillside Road. The tests were conducted to determine whether vapors from a 21 year-old petroleum release from an underground storage tank at a former gas station located nearby have migrated into basements and other areas of the homes. DNREC scientists and the environmental consultant for the project, Kleinfelder, Inc., reviewed the results of the investigation and answered questions at the workshop. Staff from the Division of Public Health answered questions relating to public health or exposure.
Kleinfelder, Inc., with oversight from DNREC’s Tank Management Branch, recently completed the environmental testing as part of a petroleum vapor intrusion study, and notified residents of the results in August and September. The study will determine if any current or future potential health risks are posed by residual petroleum contamination found in groundwater in the area.
The 1988 petroleum release occurred at 2509 Philadelphia Pike in Claymont – formally doing business as Ron’s Discount Energy Mart and Ron’s Discount Tires. 
The release came from the underground storage tank system that was located at the site. Once the problem was discovered, the tanks and contaminated soils were removed, and measures were taken to control petroleum vapors that impacted several homes on Hillside Road. However, dissolved petroleum compounds continued to be carried by groundwater from the release site toward the homes along Hillside Road. DNREC took over the cleanup actions at the site after the responsible party, Ronald Palimere, failed to take appropriate action. Over the years, the following cleanup actions have been conducted:
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1993: Removal of the tanks and over-excavation of heavily contaminated soils;
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1988-present: Testing soil and groundwater to determine the extent of the contamination;
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1989-1992: Controlling vapors that affected several homes on Hillside Road;
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2005: Injecting Oxygen Releasing Compound (ORC) into the soil beneath the upper part of Hillside Road, where contaminant concentrations remained greatest; and,
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Continued testing of groundwater to date to monitor the cleanup of the site.
ORC is a non-toxic compound that provides oxygen to the soil and groundwater to stimulate the break down of petroleum compounds by naturally occurring microbes. Following injection, groundwater quality has been monitored by sampling wells at the former gas station site, and at locations along Hillside Road. Data indicate that the ORC had a positive effect, as shown by decreased concentrations of dissolved petroleum compounds. DNREC has been monitoring conditions on a quarterly basis to ensure public safety.
The release resulted in extensive cleanup costs paid from Delaware’s Hazardous Substance Cleanup (HSCA) Fund. On July 31, 2009, DNREC issued a Notice of Administrative Penalty Assessment and Secretary’s Order to the owners, Ronald C. Palimere and Penny Hill Mobil Inc., which included $447,125 in penalties for failure to clean-up the release and $712,887 in cost reimbursement to the Department for cleanup expenses. According to Delaware law, the parties responsible for the release are liable for all past and any future costs associated with the Department’s efforts to clean up the site.
Update July 2010: The second round of soil vapor monitoring and indoor air monitoring was recently performed. In May 2010, soil vapor monitoring was performed in Zone 1 (the former Ron’s Discount Energy property), and Zone 2 Hillside Road residential properties. In June 2010, indoor air monitoring was performed in Zone 3 Hillside Road residences. Quarterly groundwater monitoring was conducted in March and July 2010. A report detailing the results of the recent soil vapor, indoor air and groundwater monitoring is in progress. Vapor mitigation for 10 Hillside Road is underway. Cracks in basement walls and floor were sealed. An inspection of the basement structure was performed to aid in the design of the full mitigation system. The basement floor sump in 9 Hillside Road was repaired to prevent vapor intrusion. The state’s urban forester, from the Delaware Forest Service, examined trees along Hillside Road. Some trees appear to be stressed, and it was concluded they are affected by a common fungus, and the observed stress is not attributed to the petroleum release.
NOTE: This project is now being funded by the American Recovery and Reinvestment Act (ARRA), also known as stimulus funding. DNREC continues its efforts to recover costs from the responsible parties.
Related documents:
Site information may be reviewed using the Delaware Environmental Navigator. The facility is listed as Former Ron’s Discount Energy Mart; facility ID # 3-000712.
Information for Review:
· General information on vapor intrusion:
For more information, please contact:
Delaware Department of Natural Resources and Environmental Control
Tank Management Branch
Chris Brown
302-395-2500
Christopher.Brown@state.de.us
