SEMS (formerly CERCLIS)

SEMS is EPA's active inventory of sites being assessed or addressed under CERCLA. It covers the pipeline that runs from initial discovery and preliminary assessment through site inspection, ranking, and, for a small fraction of sites, NPL listing. It replaced the older CERCLIS database, a name still used by many data vendors and older reports.

In a Phase I ESA

The ASTM E1527-21 Table 2 row for sites subject to CERCLA removals and CERCLA orders maps to SEMS in vendor radius reports, with a 0.5 mile search distance.

A SEMS listing means EPA looked, or is looking, at the site. It does not mean contamination was confirmed. Many SEMS sites were assessed and closed out with no action needed. Read the site's assessment status and any removal-action history in the listing detail instead of treating the acronym as a finding.

Related listings

• SEMS-ARCHIVE / NFRAP: sites EPA assessed and set aside (see the NFRAP page). ASTM's Note B cautions that NFRAP status is not a clean bill of health.
• NPL: the end of the SEMS pipeline for the highest-scoring sites.

Where the data lives

EPA publishes SEMS site data through its Superfund site search and public data downloads.