On November 20, 2023, the LSPA sent a white paper to MassDEP entitled “Recommendations for Risk Management Under the MCP for Trichloroethene Exposures Based on Updated Toxicological Information.” The paper was prepared under the auspices of the LSPA’s Technical Practices Committee by Jay Peters of Haley & Aldrich, Inc. and Marie Rudiman of EnviroRisk Solutions, LLC. 

Based on evaluation of the updated scientific evidence referenced in this paper, the LSPA concurs with the findings of EPA studies and others that the association of TCE exposure with congenital heart defects (CHDs) is not scientifically supported. The LSPA proposes that MassDEP seriously reconsider and reevaluate the weight of evidence for TCE-induced CHDs and revise its risk management framework for TCE to be based on the chronic immunological endpoint, rather than the developmental effects endpoint. The paper notes that this would have the following implications for the regulation of TCE in Massachusetts:

• The RfC for TCE would not differ from those currently in use and presented within the IRIS database. The RfCs would be the same for the developmental and chronic immunological endpoints, but would be implemented differently based on the acute nature of CHDs.

• Imminent Hazard thresholds would be identified based on TCE exposures associated with a Hazard Index of 10, rather than 1, consistent with other oil and/or hazardous materials that are not associated with ‘serious health effects’ (310 CMR 40.0955(2)), because the risks would no longer be based on developmental effects.

• More Disposal Sites with an Active Exposure Pathway Mitigation Measure (AEPMM) would qualify for a Permanent Solution because low concentrations of TCE (e.g., 6 ug/m3) would no longer be associated with an Imminent Hazard.

• Response actions to address Imminent Hazards for TCE would not differ from those applicable to other OHM (e.g., immediate removal from exposure would not be required).

In our cover letter to MassDEP, we wrote that the LSPA recognizes this is a significant request which would have an impact on the risk management framework for TCE at MCP sites. And, that we are eager to further discuss this topic with MassDEP. 

If you have comments on the paper, please send them to [email protected] and we will share them with the authors and the Technical Practices Committee.