Disposal Site West of Dike (DSWD) slit trench is the site of a formal disposal area located southwest of Million Gallon Hill, and west-NW of the DSWD PCB area. This area was first visible in a 1987 aerial photograph, and it could not be seen in a 2002 aerial photo. A test pit was dug in the northwest corner of this location, and EM readings in 2011 have detected buried objects in the soil. A wooden board and a wooden stick were observed on the site surface in 2011. The area is frequently flooded. BTEX and petroleum hydrocarbons were not identified in groundwater samples at this site, but were detected in down-gradient areas. In the slit trench area, in 2011, levels of Benzo(a)pyrene were measured at 0.566 mg/kg. Laboratory samples also measured other petroleum compounds and metals in excess of cleanup levels in soil. 2013 update - A test pit was excavated at the North end of the DSWD slit trench in September 2013. The test pit was centered on a geophysical anomaly previously identified. The test pit did not encountered a redish brick material and wood debris layer at approximately 3 feet below ground surface. 3 soil samples were collected. No metal debris was identified.