During the study of a recent well-documented subsurface hydrocarbon spill originating from a tank farm in Virginia, measurements of vapor phase hydrocarbon concentrations were gathered during the placement of monitor wells, and subsequent concentrations were measured using hand-driven as well as hydraulic-press-driven soil probes. Several conclusions were made. (I) The subsurface hydrocarbon plume (primarily diesel fuel, jet-fuel, and gasoline) rests on the local water table at depths of 10-40 ft. (2) The plume advanced rapidly (as much as 350 ft / yr) along subsurface soil partings related to near-vertical foliation in the local bedrock. Hydrocarbon in the soil vapor was detectable before phase-separated hydrocarbon (PSH) was detected in monitor wells. (3) Organic analyses on PSH taken from monitor wells revealed that a vapor plume rose up fi om the PSII blume. The organic vapor analyses closely delineated the margin of the plume. The concentration of vapor was not associated with the thickness of the PSH nor with the depth of the plume.