DTSC Approval of April B478 Vapor Pin Report

May 24, 2017

Environmental consultants for the neighboring Campus Bay site installed a vapor pin in Richmond Field Station B478 in 2016 in order to sample soil vapor under the building. The sampling was required by the Department of Toxic Substances Control to determine if soil vapor under the building was impacted by increasing concentrations of vinyl chloride found in samples of groundwater from piezometer PZ-12 near the south end of B478. A soil gas sample collected through the vapor pin on January 31, 2017 found no detectable target volatile hydrocarbons. Based on the sampling completed the solvents detected in the groundwater do not pose a risk to the occupants of B478. The results of the sampling were published in an April 12, 2017 Technical Report by Terraphase. The report recommends no further sampling. The report was approved by DTSC on May 24, 2017.