Appropriate toxicity criteria for human health risk assessments are critical for protecting the public from toxic materials. The federal government establishes minimum levels of protection, a floor so to speak, and California policy has long required the use of California standards when more protective than the federal ones. Consistent with this, on 11 November 2016, DTSC proposed regulations, which would have required the use of the most protective toxicity criteria.
DTSC has now, however, backed off from that commitment to public protection and issued a changed proposed rule that no longer would require the use of the most protective standards. Indeed, as shown in our analysis below and in the attached comparison tables we have prepared, for many of the contaminants of concern, the proposed rule would mandate the use of the weakest criteria. No rationale has been provided for this backsliding, nor can there be any.