Risk Evaluation Guidance
IDEM periodically issues technical information and announcements to supplement the Remediation Closure Guide. This page lists these resources chronologically, with newer information and announcements appearing first.
- Attenuation Factors:
- On October 20, 2015, IDEM issued a memorandum [PDF] to announce its acceptance of the attenuation factors described in the U.S. Environmental Protection Agency’s vapor intrusion guidance from June 2015. IDEM later issued the Attenuation Factors Technical Guidance Document [PDF] on September 29, 2016.
The technical information that appears below has been superseded by newer guidance. However, some responsible parties may be eligible to use superseded guidance when addressing releases.
- Risk Integrated System of Closure (RISC) User Guide (June 2010)
- RISC Technical Guide (February 15, 2001)
- TPH Fractionation Tool (contact the Office of Land Quality to request this document.)