This site is one of the "Superfund" hazardous waste sites in Colorado. A site qualifies for the National Priorities List (NPL or Superfund list) when the U.S. Environmental Protection Agency (EPA) determines there is a release or threatened release of hazardous substances that may endanger public health, welfare or the environment. In Colorado, the lead agency for Superfund remediation may be either the EPA or the Colorado Department of Public Health and Environment (the state health department).
Fourth Five-Year Review Report September 2012
The Chemical Sales Company facility is located at 4661 Monaco Street in Adams County. The identified plume of groundwater contamination extends from north of Sand creek to Quebec Street on the east, Holly street on the west, and East 86th Avenue on the north. The entire Superfund site covers five square miles.
The site was first developed in 1962 with construction of a warehouse. Operations onsite have included the storage and repackaging of bulk chemicals from rail cars and drums. In 1981, a random sample of municipal drinking water identified groundwater in South Adams County Water Supply District (SACWSD) as contaminated with organic chemicals. Chemical Sales Company was found to be the main source of this contamination. the site was placed on the list of Superfund sites in August 1990.
Volatile organic compounds (VOCs) are the contaminants of concern at the site. The VOCs of greatest concern due to the level and frequency at which they have been detected in the groundwater are: tetrachloroethylene (PCE); trichloroethylene (TCE); 1,1-dichloroethane (1,1-DCA); 1,1-dichloroethene (1,1-DCE); and vinyl chloride. Long-term, chronic exposure to the contaminants is the major health risk.
The greatest potential for health risk to residents of the area is from ingestion of contaminated groundwater, dermal (skin) exposure to contaminated water, or inhalation of vapors from groundwater. Residents who reside in the area of contaminated groundwater and use shallow (less than 100 feet) groundwater from residential wells for domestic purposes may be receiving contaminated water. Most area residents receive drinking water from the municipal drinking water supply that has been treated by the Klein Water Treatment Facility since 1989 to remove VOCs. Surface soil, air and surface water do not pose a signivicant health threat.
In 1985, U.S. EPA began the conversion of about 400 residences from private shallow wells to municipal water. In 1989, the Klein Water Treatment Plant, which treats all South Adams County Water Supply District water, was completed. EPA removed leaking and corroded drums in 1989. The remedies selected for further clean up were: treat contaminated soils through soil vapor extraction; treat contaminated groundwater through air sparging and soil vapor extraction; treat the extracted vapors with a resin adsorption unit; and use groundwater extraction wells to prevent further migration of contamination. Remedial design of the source area remedy was completed in May 1998. Construction fo the soil vapor extraction system and air sparging system was complted in December 1999. The facility is up and running and is currently meeting all the air and water permit requirements. To date, the soil vapor extraction system has treated over 2.5 million cubic feet of soil vapor. The monitoring wells have been showing a downward trend of VOC concentrations since the system has been running. Due to a stagnation point in the cleanup, the state hired a contractor to inject a modified Fenton's reagent in the source area. In a cost savings for the State/EPA, the state has taken over the everyday operations at the plant site and will continue running the treatment system.
Jim Lewis, State Project Manager
Jeannine Natterman, State Community Involvement Coordinator
(888) 569-1831 ext 3303 toll-free outside the 303/720 area code
Armando Saenz, EPA Remedial Project Manager