Chemical Sales Co.

Site project managers

Shaun Cwick, P.G.
State Project Manager

Colorado Department of Public Health and Environment
4300 Cherry Creek Drive South
Denver, CO 80246-1530
Email: ross.davis@state.co.us

Andrew Schmidt, P.G.
Remedial Project Manager
U.S. EPA Region 8 (EPR-SR)
1595 Wynkoop Street
Denver, CO 80202-1129

  Records Review

This is a National Priorities List (NPL), or "Superfund," hazardous waste site. While we’re the lead agency for remediation of the site, the EPA Superfund Program provides technical support and input on all remediation-related activities to ensure the objectives of the Superfund program are met.

Site summary


  • 4661 Monaco St., Denver.
  • Covers five square miles in Adams County.


  • The site was first developed in 1962 and was used for the storage and repackaging of bulk chemicals from rail cars and drums.
  • In 1981 a random sample of municipal drinking water identified organic chemicals in groundwater and this site was determined to be the main source of the contamination.
  • 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 site was placed on the list of Superfund sites in August 1990.

Environmental concerns


Contaminants include volatile organic compounds (VOC) like:
  • 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 to residents of the area from:
    • Ingestion of contaminated groundwater.
    • Skin exposure to contaminated water
    • Inhalation of vapors from groundwater.
  • Most area residents receive drinking water from the municipal drinking water supply that has been treated to remove the contaminants.
  • Residents who use shallow (less than 100 feet) groundwater from residential wells for domestic purposes may be receiving contaminated water.
  • Surface soil, air and surface water do not pose a significant health threat.

Site remediation

  • EPA began the conversion of about 400 residences from private shallow wells to municipal water in 1985.
  • The Klein Water Treatment Plant, which treats all South Adams County Water Supply District water, was completed in 1989.
  • EPA removed leaking and corroded drums in 1989.
  • Cleanup activities included:
    • Treating contaminated soils through soil vapor extraction.
    • Treating contaminated groundwater through air sparging (A process used to treat soils and groundwater contaminated by volatile organic compounds.) and soil vapor extraction.
    • Using groundwater extraction wells to prevent further migration of contamination.
  • Construction of the soil vapor extraction system and air sparging system was completed in 1999.
  • Since the treatment systems became operational, monitoring wells have shown a downward trend in contaminant concentrations.
  • To save on costs, we have taken over the everyday operations at the plant site and continue running the treatment system.

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