Raising the interesting question, what does the oxymoron “Interim Final” mean?, MassDEP recently released its Interim Final Vapor Intrusion Policy (pdf).  According to MassDEP, “Final” means that the public can use the policy as a guidance document that can be cited.  However, be aware that the guidance is intended to serve as a transition document until MassDEP promulgates revised vapor intrusion regulations this summer.  At that point, the guidance will be rendered out-of-date and in need of revision – hence the “Interim” designation. 

Notably, for developers planning to build, MassDEP has created three potential scenarios, each one calling for a different approach depending on the concentrations of VOC contamination found in the soil and groundwater near the building site.  The approaches range from doing nothing to (1) installing a vapor barrier, (2) building an active sub-slab depressurization system, or (3) continued sampling of the site.  The flow chart on page 7 of the guidance depicts the screening process to determine which scenario should apply. 

For now, MassDEP “generally does not intend the guidance to be overly prescriptive,” and states that it “should not be considered as mandatory.”  While these statements soft-pedal how forceful MassDEP will be in requiring compliance with the guidance, after all the work and controversy surrounding the policy, it seems unlikely the agency will allow much, if any, variation from the guidance’s prescribed procedures.  MassDEP expects comments based on actual use of the guidance, which will be considered in formulating the anticipated new regulations later this year.