The MOE has released a guidance document called “Technical Update: Use of MOE Component Values in Risk Assessments Submitted under the Record of Site Condition Regulation (O. Reg. 153/04)” (March 2010). The Technical Update is intended to assist Qualified Persons for Risk Assessment (“QPRAs”) in the preparation of risk assessments during the transition to the recently released (and generally more stringent) standards for soil and groundwater which come into force on July 1, 2011. These new standards are based on the lowest applicable “component value”, which are set out in a “Rationale Document” (i.e. for any given contaminant, different component values are determined in order to guard against different types of risks, and the lowest of these values is selected as the generic standard for that contaminant).

The Technical Update states that QPRAs may continue to use the “component values” that are set out in the former (1996) Rationale Document for Records of Site Condition filed before July 1, 2011. However, since those former component values may no longer reflect the best science, “the QPRA should always describe the justification process being relied upon when selecting component values”. Moreover, “[i]n order to ensure the continued protection of human health and the environment, the MOE may, on a case by case basis, request additional justification regarding the use of component values.” QPRAs may use the component values set out in the new Rationale Document, which “are considered to be current science by the MOE”.