Colorado
Conditional closures
Colorado conditional closures
The Colorado Department of Public Health and Environment (CDPHE) has a Policy for Conditional Closure of Low-Threat Sites With Residual Ground Water Contamination. CDPHE says the policy allows closure of sites where groundwater remains contaminated at levels that exceed the Colorado groundwater standards.
In a Phase I ESA
ASTM E1527-21 does not name conditional closures among its standard record sources. The term matters because it tells you what was left behind: a conditionally closed site is closed with contaminated groundwater still in place. Four details shape how to read one.
- Closure has a stated meaning. CDPHE says closure in this context means that remediation and groundwater monitoring may cease and an environmental covenant is placed on the property. So monitoring data in the file may stop at the closure date. CDPHE's page links its list of sites with environmental covenants and use restrictions, described on the environmental covenants page. Check whether the site is on it, and read what the covenant restricts.
- Corrective action sites can get a different limit. If the site is subject to hazardous waste corrective action, CDPHE says an Alternate Concentration Limit can be set for groundwater at the site under the hazardous waste regulations. Ask what limit was set and for which constituents.
- More than one party can ask. CDPHE's division, the site's owner or operator, or other responsible parties may propose conditional closure.
- Some sites cannot use it. Superfund National Priorities List sites and what CDPHE calls NPL-caliber sites are ineligible, and so are regulated units at hazardous waste treatment, storage and disposal facilities.
The policy itself is a document that CDPHE's page links. It was not read for this page, so the tests a site must pass to count as low-threat are not stated here.
Conditional closure is a CDPHE policy. Petroleum tank releases are closed by another agency under its own tiers; see Petroleum release closure criteria.
Where to look a site up
- The page read gives no list of conditionally closed sites. It links CDPHE's list of sites with environmental covenants and use restrictions.
- CDPHE's Hazardous Materials and Waste Management Division links an interactive records map and a records search.
Getting the file
The division takes requests through the form on its records review page or at cdphe_cora_hmwmd@state.co.us. The route is described on the records review page.
Sources
Colorado Department of Public Health and Environment pages, read October 7, 2026, no modified date shown: