Orphan Sites

DEQ established a process for identifying orphan sites and prioritizing the resources available to clean them up. For more detailed information regarding orphan sites, please review the Orphan Site Identification, Evaluation, and Prioritization Process document. 

To see the list of orphan sites, as well as a map of orphan sites in Wyoming, click here

Definition of an Orphan Site

Under the Environmental Quality Act “Orphan Sites” are defined as:

  • Sites where the DEQ determines that there is no viable party that is responsible for causing or contributing to the contamination present at the site.
  • Sites where DEQ has issued a no further action letter, and where there is a subsequent discovery of contamination that was present at the site when the no further action letter was issued, but:
    • Was not known to the site owner or DEQ at the time the no further action letter was issued, provided that a comprehensive and complete site characterization was conducted by the owner.
    • Is not the result of activities conducted on the site after the no further action letter was issued.
    • Does not constitute an imminent or substantial endangerment to human health or the environment that is being addressed by the holder of the no further action letter, to a reopening of the no further action letter under the Environmental Act.
  • Spill sites where DEQ determines that the person responsible for the spill cannot be identified, or where DEQ must take prompt action to prevent hazards to human health or the environment at a site where a responsible party fails to act promptly.


To learn more about how orphan sites are evaluated, how potential orphan sites are identified as actual orphan sites, and how orphan sites are prioritized, click here