Vapor Intrusion in California – Still Up in the Air
The Department of Toxic Substances Control (DTSC) Human and Ecological Risk Office (HERO) released an update to its Human Health Risk Assessment Note (referred to as HERO Note 3 and available here) this week but did not provide more clarity on which soil vapor intrusion screening levels should be used to evaluate redevelopment of brownfield sites in California. In short, HERO Note 3 now recommends comparing soil vapor concentrations to both DTSC’s current screening levels (based on building specific attenuation factors)…