The Chemical Sales (New Location) (Operable Unit 1) site is an active chemical sales and storage facility in Commerce City, Adams and Denver Counties, Colorado. Land use in the area is predominantly industrial, and there are six residences located on the northern portion of the site. The site is bounded by Sand Creek to the north and lies within the 100-year floodplain of the creek. An estimated 30,000 people who reside near the site use the alluvial aquifer as the principal source of drinking water. Since 1976, Chemical Sales (CS) has used the site to store and sell organic chemicals and acids. Between 1985 and 1990, three onsite chemical releases of hazardous substances into the soil and ground water from the CS facility were reported. In 1985, approximately 200 gallons of methylene chloride were spilled into onsite soil during a chemical transfer. The second release was in 1986 when rain water contaminated with several VOCs was discharged into a nearby drainage ditch. The third release occurred in 1990, when approximately 3,700 gallons of methanol were spilled on the ground surface near the CS tank farm. The Record of Decision (ROD) addresses remediation of soil and ground water contamination south of Sand Creek, as OU1. Future RODs will address other site contamination including the ground water plume and associated contamination (OU2), and residential exposure to contaminated wells and domestic water from the municipal water supply (OU3). The primary contaminants of concern affecting the soil and ground water are VOCs including PCE and TCE. The selected remedial action for the site includes treating contaminated onsite soil using vapor extraction; treating air emissions with catalytic oxidation; recirculating exhaust from the catalytic oxidation system into the contaminated soil; pumping and onsite treatment of ground water in the source area and plume area using air stripping, followed by reinjecting the treated water from the source area wells and
reinfiltrating treated water from the plume area through onsite discharge.