Chemical spillage and waste disposal during 40 years of manufacturing vinyl wallcovering had contaminated portions of a field site with various organic chemicals, predominately xylene and dioctyl phthalate. Laboratory treatability studies were conducted on core samples obtained from the site. The objective was to determine whether natural biodegradation processes would remediate the site. Nine core samples were collected at three locations in 3-ft increments from site locations of low contamination, moderate contamination, and high contamination. Analysis of a nine-sample composite showed that 95 percent of organic compound contamination was dioctyl phthalate. All core samples contained sufficient nitrogen and phosphorus to support viable soil microbiological processes. Extrapolating from laboratory data rates and assuming ideal field conditions, the predicted total time to naturally cleanse the site to less than 10 ppm pthalate would be 3 years and 10 years, respectively, for the moderate and high contaminated areas. Biodegradation of dioctyl phthalate was enhanced by the presence of xylene in a separate microcosm study.