Health Risk Limit Rules for Groundwater
Below are Statements of Need and Reasonableness (SONARs) from previous years. Note: While SONARs contain information about why the guidance values were promulgated, they are written for a specific step in the rule development process. The SONAR will not show chemicals that were added or deleted during the rulemaking process and it does not reflect all information that was included in the final Health Risk Limit rule.
1993 SONAR (PDF: 260KB/97 pages)
Contains information about HRLs adopted in 1993 and 1994.
2008/2009 SONAR (PDF: 1.05MB/196 pages)
This SONAR provides a thorough description of the scientific methods and principles used to develop HRLs, in addition to describing HRLs adopted in 2008/2009. For definitions of terms, see the 2009 HRL SONAR Glossary (PDF: 61KB/9 pages)
2010/2011 SONAR (PDF: 1.34MB/164 pages)
Provides information on HRLs formally adopted in March 2011.