CSXT owns and operates Benning Yard located at 225 33rd Street, SE, Washington, D.C. Benning Yard is an active railroad switching yard. Historically, a portion of Benning Yard was used to store and dispense diesel fuel to locomotives. In 2004, a new office building and parking facility were constructed in the area where fueling operations had previously been conducted. Subsurface hydrocarbon contamination was observed during this construction and, subsequently, it was determined that hydrocarbon-impacted groundwater was seeping into adjacent Fort Dupont Creek, a tributary to the tidal Anacostia River. Although Fort DuPont Creek receives inflows from CSXT Benning Yard Outfall 002, it also receives runoff from the remaining portion of the 376-acre Fort Dupont Creek watershed upstream from CSXT Benning Yard. Further investigations of the observed hydrocarbon contamination at Benning Yard revealed the presence of a light non-aqueous phase liquid (LNAPL) plume in the water table aquifer and, on occasion, the presence of a petroleum sheen on Fort Dupont Creek. The groundwater in the diesel spill area at CSXT Benning Yard flows northeast towards Fort Dupont Creek. Historically, free product has been present in the monitoring wells located adjacent to Fort Dupont Creek where product level thickness has been less than one foot. A Consent Decree (CD), signed by the District of Columbia on behalf of DOEE and CSXT, was entered on 17 June 2011 by the Superior Court for the District of Columbia to address, among other things, the release of hydrocarbons to Fort Dupont Creek. To address the contamination, CSXT prepared a corrective action plan (CAP) in February 2012 which included the excavation of petroleum-impacted soils, installation of oxygen releasing compound in trenches at the bottom of the excavation, and backfilling with clean fill. Site cleanup activities were completed in 2016. The CAP activities are summarized in the CAP Construction Completion Report dated June 23, 2016. Currently, CSXT is conducting post remedial groundwater monitoring.
A sediment investigation including Fort Dupont Creek and the Anacostia River was conducted in 2011. Surface sediment grab samples were collected at 18 locations on Fort Dupont Creek and 35 locations on the Anacostia River. Sediment core samples were collected at 18 of the surface sampling locations. All samples were analyzed for TPH-DRO, VOCs, SVOCs, metals, pesticides, and PCB Aroclors. Anacostia River samples were also analyzed for 209 PCB congeners and PAH fingerprinting analyses. The total PAH analyses reported concentration results for 51 PAH compounds and alkylated PAH groups. Surface sediment and subsurface sediment samples were collected. Subsurface samples were collected from the depths of 0.5 to 1.0 foot, 1.0 to 2.0 feet, and 2.0 to 3.0 feet below the river bottom. The results of this investigation are summarized in Analytical Sampling Results Report dated April 4, 2013.
Administrative Record File