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More than three-and-a-half years ago, the Maryland Department of the Environment responded to a major release of over 26,000 gallons of gasoline in the northern Baltimore County town of Jacksonville. The site, an ExxonMobil gas station located at the intersection of Jarrettsville Pike and Paper Mill Road, is now closed and all storage tanks and piping have been removed. In 2008, MDE settled a lawsuit against ExxonMobil Corporation for the gasoline spill that significantly impacted the Jacksonville community for $4 million, making this the largest state environmental penalty ever levied by MDE.
Cleanup actions resulted in the recovery of an estimated 10,000 gallons of liquid gasoline from the original release with additional product being recovered in the form of vapor and groundwater dissolved constituents. This multi-million dollar recovery effort is being performed utilizing 87 specially installed wells within the study area. Two highly advanced groundwater treatment systems are processing the contaminated groundwater collected. To date, over 48 million gallons of groundwater have been withdrawn and treated through these systems. Although this is a significant withdrawal of groundwater, MDE has not detected any adverse effect on groundwater quantity in the Jacksonville area.
Since the leaking pipe was discovered on February 17, 2006, MDE staff have spent many hundreds of hours directing recovery efforts, overseeing site work, and reviewing investigation and remediation activities. MDE’s investigation has extended to a half-mile radius around the station into the Jacksonville community and required the installation of nearly 300 monitoring/recovery wells in the study area.
As the cleanup progresses, MDE continues to review and approve sampling schedules for water supply wells within the Jacksonville area. MDE will continue to evaluate any proposed changes to sampling schedules as site conditions change and must approve any modifications to the currently approved schedule. Currently, over 270 properties are sampled on a routine basis to monitor for gasoline compounds. Since the initial release, MDE required ExxonMobil to place 14 water supply wells on individual carbon filtration treatment systems. Twelve of the 14 wells have shown gasoline compounds above regulatory action levels. As evidenced by ongoing water quality sampling, the individual treatment systems are functioning properly and are providing clean water for all 14 water supply wells.
Groundwater testing has shown that the spread of dissolved gasoline traveled further in the northeast direction from the site as compared to the southwest. This travel is due to the geologic features in the area. Generally, groundwater recovery efforts have controlled further movement of the gasoline plume and, overall, MDE is observing a decreasing trend in the groundwater contamination levels and the size of the plume in many areas throughout the study area. It is now planned to begin the testing of the remediation systems to determine which sections of the system are producing only clean water or soil vapor and which sections can be safely turned off. This testing will be closely monitored by MDE and will be conducted in a way that will allow a recovery system section to be turned back on, should contamination levels increase in the future. MDE remains alert to the fact that the subsurface rock fractures within Jacksonville may allow contaminated groundwater to migrate out of the current recovery zone. This is the reason MDE continues to order the groundwater sampling and monitoring within the Jacksonville area.
It is MDE’s goal to reduce the amount of groundwater being withdrawn from the area as soon as recovery operations allow. Currently, clean treated groundwater is being discharged under the provisions of a State and Federal discharge permit into Greene Branch and Sawmill Branch located southwest and northeast of the site. MDE verifies that the quality of the discharge groundwater is maintained in compliance with the discharge permit through quality assurance testing and contractor sampling and report oversight.
The Department understands the level of concern that this release has caused the Jacksonville community and is very appreciative of all the property owners who have given access for the MDE monitoring and cleanup activities. MDE will continue to oversee the cleanup until clean groundwater in Jacksonville is fully restored.
Click here to visit MDE’s website for site updates and maps of the area that show sampling frequency, monitoring well locations and other site data. If the Department may be of assistance, please do not hesitate to the MDE Oil Control Program, at 800-633-6101, ext. 3442.
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