The Vertac site, a former herbicide and pesticide manufacturing facility in Jacksonville, Arkansas, is comprised of an onsite and offsite area. Production of herbicides and pesticides, including 'Agent Orange,' began in 1948 and resulted in extensive onsite contamination. The offsite contamination, which is the focus of the Record of Decision (ROD), resulted from improper discharge of wastewater generated during onsite operations. Prior to 1960, untreated wastewater was discharged directly into Rocky Branch Creek, which flows into Bayou Metro a few miles south of the site. Beginning in the 1960s, wastewater was discharged to the city's Old Sewage Treatment Plant, which had been upgraded with a pretreatment facility that included an aerated lagoon and oxidation ponds (West Wastewater Treatment Plant). A solvent treatment process was later added to remove dioxin from the product. The process, however, created contaminated liquid and solid waste residues that were drummed and buried or stored onsite until 1987, when pesticide production ceased. The primary contaminant of concern affecting the soil, sediment, and sludge is 2,3,7,8-tetra-chlordibenzo-p-dioxin.