Earlier this month, the American Society for Testing and Materials (ASTM) published a new standard for the assessment of vapor intrusion into structures on property involved in real estate transactions (ASTM 2600-08). You can read the ASTM press release here.
Generally speaking, vapor intrusion is an indoor air quality condition that occurs when chemicals volatilize from impacted soil and groundwater beneath a building to fill that building with potentially hazardous vapors.
Vapor intrusion has become a significant environmental concern in recent years as properties that were formerly manufacturing facilities, gasoline stations, dry cleaners, or for other reasons have impacted soil and/or groundwater are redeveloped into offices, residential buildings, or mixed use facilities. Until ASTM took the responsibility upon their shoulders, there has been a lot of discussion and inconsistencies about the appropriate methods of measuring the vapor intrusion impact within structures and the appropriate methods of estimating the risk associated with that impact. This new standard is a significant milestone for this emerging area of property due diligence, but I feel that this will be a long and tortuous path with many more milestones to come.
This assessment standard goes a long way to identify the process of assessing the potential Vapor Intrusion Condition (pVIC) or the Vapor Intrusion Condition (VIC) and how the assessment of the VIC relates to the previously established due diligence procedures of a Phase I (ASTM 1527-05). The vapor intrusion standard also provides a prescriptive method on how to identify if a pVIC exists and when a Phase I would identify the need for a vapor intrusion screen to be performed. What the standard does not do is provide a prescriptive method for determining if vapor intrusion results in an indoor air quality level that presents a threat to human health and the environment; at this point the standard directs the user to follow appropriate and applicable government guidance documents. As I have stated in my previous posts, here in Southern California, the convoluted regulatory community could potentially make this part of the site assessment grind to halt or worse underestimate the thret to human health and the environment.
This problem is only exaserbated by the fact that ASTM is only an engineering standards organization, not a regulatory body. Even though this standard is published by ASTM and will be used quite frequently almost immediately by due diligence professionals like myself; it may be decades before state and/or local regulatory agencies begin to recognize site assessments performed and published in full compliance with the standard.
There will be more to come in the saga of vapor intrusion, stay tuned!