In December 2003, EPA issued its Hazard Ranking System (HRS) Assessment of Area IV of SSFL. The EPA's conclusion was that Area IV of SSFL did not rank high enough to be listed on the National Priorities List (NPL) or to be a CERCLA (Superfund) site.
This process determines whether site hazards qualify the site for placement on the National Priorities List (NPL) or the Superfund list and whether federal response is required. EPA determined that "Further remedial site assessment under CERCLA (Superfund) is not required because...the site does not qualify for further remedial site assessment under CERCLA (No further remedial action planned - NFRAP)"
EPA's rationale for these determinations were that:
In order to qualify for listing as a CERCLA (Superfund) site, the HRS has to assign a hazard rank measure of greater than 25. Typical Superfund sites have hazard ranking measures of 50. Area IV of SSFL ranked at 1.08. For more information, read the EPA fact sheet about their assessment.