This guidance was developed by the U.S. Environmental Protection Agency (EPA) Region 4's Superfund Division’s Scientific Support Section (SSS) risk assessment staff to update and replace all previous Region 4 Human Health Risk Assessment Supplemental Guidance and to supplement the Agency guidance documents on site-specific Human Health Risk Assessment (HHRA): the Risk Assessment Guidance for Superfund (RAGS), Volumes I, II and III (EPA, 1989a, 1989b, 2001a). RAGS was developed as broad guidance, and the purpose of this guidance is to clarify and extend RAGS as interpreted and applied in Region 4.

This supplemental guidance provides direction and does not constitute rulemaking by the Agency. The intent of this guidance is to aid in the development of high-quality risk assessments consistent with the expectations of the SSS in its oversight role.

• HHRA Regional Supplemental Guidance Report (March 2018 Update) (PDF)(36 pp, 409 K, 03/22/2018)