Sand Creek Industrial covers 550 acres across Denver and Commerce City, Colorado. Starting in the 1940s, the land hosted an oil refinery, a pesticide manufacturer, a herbicide chemical plant, and a landfill. Those operations left soil, groundwater, surface water, and air contaminated with a wide range of hazardous chemicals. The EPA placed the site on the National Priorities List in September 1983 and organized cleanup into six operable units, each targeting a different area or problem, such as contaminated organic soils, acid pits, the Holly Landfill, groundwater, and landfill gas.
More than 90 contaminants of concern have been identified at the site. Chlorinated solvents including trichloroethene, tetrachloroethene, benzene, and vinyl chloride appear in groundwater, surface water, air, and free-phase liquid layers. Metals such as arsenic, cadmium, lead, chromium, and mercury are present in groundwater and surface water. Pesticides including DDT, dieldrin, chlordane, and lindane are found in soil and groundwater. Additional contaminants include antimony, barium, manganese, nickel, vanadium, and fluoride.
Active cleanup ran from 1990 to 1994 and included demolishing contaminated buildings and tanks, excavating and incinerating contaminated soil, treating groundwater, removing liquid chemical plumes, collecting landfill gas, and installing security fencing. The EPA deleted the site from the National Priorities List in December 1996. Responsibility for operation and maintenance transferred from the EPA to the state of Colorado in June 2022. Ongoing work includes landfill gas and groundwater monitoring, upkeep of landfill covers and fences, and institutional controls that restrict how land and groundwater can be used.
The most recent five-year review, completed in September 2025, found that current cleanup actions protect human health and the environment in the short term. Long-term protectiveness depends on adding and maintaining additional institutional controls. The EPA and the Colorado Department of Public Health and Environment will work with Denver and Adams counties to establish any needed rules under local laws and Colorado's environmental covenant statute. The site has not yet achieved sitewide ready-for-anticipated-reuse status, though redevelopment is already active. As of December 2024, 69 businesses on-site employed 1,652 people and generated about $243 million in annual sales.
Community members with questions can contact the EPA Community Involvement Coordinator. For technical questions, contact the Remedial Project Manager. For state-related questions, contact the Colorado Department of Public Health and Environment. Public records are available at the EPA Superfund Records Center in Denver at 1595 Wynkoop Street.
