In April 2016, the Massachusetts Department of Environmental Protection (MassDEP) Bureau of Waste Site Cleanup (BWSC) announced they intended to screen approximately 1,000 closed sites with known trichloroethylene contamination to assess if TCE concentrations at these sites posed an imminent health risk based on a new understanding of health risks.  This assessment included sites that had previously been formally clean closed by MassDEP based on earlier cleanup standards

These assessments were initiated due to a 2011 revision to US EPA toxicity information that resulted in MassDEP developing more stringent screening levels for TCE in indoor air and groundwater.

MassDEP encouraged property owners and/or Potentially Responsible Parties (PRPs) of previously closed TCE sites not to wait for the MassDEP to contact them; rather encouraged them to review existing site information and begin to evaluate current conditions to determine if there is a potential for ongoing exposure to TCE.

Changes in cleanup standard due to new health studies at TCE sites have major ramifications for property owners and developers.  In light of increased stringency of cleanup standards due to new health studies, property owners need to consider what environmental regulatory agencies may do to address sites previously deemed sufficiently clean under prior guidance and cleanup standards.