Final Remedial Action Guidelines From Maine DEP Published, Including New PCE Cleanup Levels

After several years of formal and informal proposals, the Remedial Action Guidelines (RAGs) have finally been revised, and are now effective, thanks to action by the Maine Department of Environmental Protection (DEP).  The RAGs are used for clean up of contaminated property, addressing hazardous substance releases, and in the Voluntary Response Action Program (VRAP).

The RAGs will be of interest to anyone who has to address contaminants in the environment, whether in soil, groundwater, or indoor air.  These RAGs incorporate new changes in worker exposure scenarios and adopts the “single-contaminant” approach of 1 in 100,000 chronic risk levels, clarifying the application of the RAGs at many sites where there may in fact be more than one contaminant present. 

Notably, the DEP has adopted new RAGs and Maximum Exposure Guidelines for drinking water/groundwater for Perchloroethylene (PCE), a common solvent used extensively in the past in multiple applications, including dry cleaning. These new levels are based on new studies, and are one to two orders of magnitude higher; they have already resulted in DEP conclusions that prior remedial actions requested are now unnecessary.  Polycyclic Aromatic Hydrocarbons (PAHs) in urban and road-runoff settings are among the other RAG changes that are having an impact.

The links to the relevant DEP documents can be found here.  DEP continues to emphasize that the RAGs can be supplemented or replaced by a site-specific risk assessment, though that can be an additional cost.