Site evaluation activities at the Site were performed by the Maryland Department of the Environment (MDE) per agreement with EPA Region 3’s Site Assessment Branch beginning in March 2014. A Site Inspection report was prepared by MDE in April 2015 followed by more extensive vapor intrusion investigatory work by MDE at three homes in August, November and December 2015. In February 2016, based on elevated subslab and indoor air analytical results for PCE found in two of the three homes sampled, MDE began plans to install VI mitigation systems at the two homes.
Based on geologic factors, it appears that VI systems may be unusually costly. MDE has the ability to install a system at one home but officially requested EPA to install a system at the other home as well as take the lead for further investigatory and mitigation activities. EPA agreed to do so.
EPA collected indoor air samples at the second home and confirmed that PCE readings exceed acceptable levels particularly in light of the inhabitant demographics and living arrangement. This led to the preparation of this Special Bulletin. The OSC plans to conduct further investigatory work in additional homes and take measures to determine the extent of the contaminant plume.