We are concerned that Connecticut applies significantly less stringent standards than EPA recommends when deciding to investigate vapor intrusion of trichloroethylene (TCE) and tetrachloroethylene (PCE). Following is the disparity that concerns us:

EPA's safety threshold for vapor intrusion investigation of TCE (set in 2002):
5 ppb (this includes residential and industrial settings)

CT DEP's threshold (RSR) for vapor investigation of TCE (proposed in 2003):
Residental: 27 ppb (5X less protective than federal guidelines)
Industrial: 67 ppb (13X less protective)

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EPA's safety threshold for vapor intrusion investigation of PCE (set in 2002):
5 ppb (this includes residential and industrial settings)

CT DEP's threshold (RSR) for vapor investigation of PCE (proposed in 2003):
Residental: 340 ppb (68X less protective than federal guidelines)
Industrial: 810 ppb (160X less protective)


Connectict's current vapor intrusion guidelines (click image to enlarge)

According to these Connecticut regulations, before Connecticut will investigate the potential for TCE or PCE vapor intrusion, Connecticut's residents and workers may be subjected to 5-160 times more TCE and PCE exposure than federal guidelines recommend.

Connecticut must revise these inadequate regulations and re-open old hazardous waste and contamination site investigations to rule-out vapor intrusion as dictated by (at least) current federal guidelines. More on this to come...