There could be new morestringent standards to measure vapor intrusion in California—ormaybe not. It seems to depend on the agency. The California EPA,which oversees several environmental agencies throughout the state,has not adopted new measurement standards are vapor intrusion, butregional agencies have. These agencies, which include regionalwater quality control boards, have begun employing the federal EPAguideline, and it is causing a lot of uncertainty for propertyowners.

“The origin is still a bit mysterious,” PrestonBrooks, partner at Cox, Castle &Nicholson, tells GlobeSt.com. “There was a 2015 standardthat was adopted by the US EPA, and I think that at the CaliforniaEPA level, there were good reasons not to follow suit. The standardwas based on East Coast conditions, and there are some significantdifferences between East Coast and West Coast vapor intrusion.”

California officially uses the Johnson and Ettinger model forvapor intrusion. The model anticipates that there will bedifferences between individual properties that could impact themeasurement of vapor. Brooks says that it is an effective model forCalifornia, and to his knowledge, no objections. “There was notmovement to shift from the Johnson & Ettinger model, he says.“There was nothing wrong with the system that we had. It wasconservative and health protective. So, why fix something thatisn't broken? Yet, that seems to be what has happened.”