On June 14, 2010, ASTM published E 2600-10, Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions. This standard replaces E 2600-08 published in March of 2008.

The newly revised standard focuses solely on screening for the likelihood of migrating vapors volatilized from a contaminated source to encroach upon the subsurface of a property involved in a real estate transaction and create a vapor encroachment condition (VEC). Two tiers for screening are included in the practice. The first tier is based upon the existence of known or suspect contaminated sites in the area. The second tier is more comprehensive and investigates specific characteristics associated with the contaminated plumes from these sites, or if no plume information is available, relies on sampling.  If the likelihood exists for vapors to reach the subsurface of the property, further investigation that is beyond the scope of this practice would be necessary to determine if vapor intrusion is occurring into any buildings on the property.

Of particular note in the standard is the completely revised Legal Appendix that discusses the relationship between this standard and the E 1527-05 Phase I standard. In simple terms, the E 1527-05 standard (which complies with AAI) includes in its REC definition the EP's need to consider hazardous substances and petroleum products on the target property or migrating to the target property no matter what form these substances take, i.e., solid, liquid or vapor. The E 2600-10 standard merely provides a methodology for the EP to accomplish this for vapors. If vapors can reach the target property (thereby creating a VEC), the EP conducting the E 1527-05 Phase I would then have to decide whether or not the VEC constitutes a REC. This would be analogous to the EP finding in the Phase I investigation the potential for a contaminated groundwater plume to reach the target property. The EP would then have to determine if this situation is a REC.

It is anticipated that the screening under ASTM E 2600-10 will eventually become a routine part of an AAI-compliant Phase I environmental site assessment. A number of institutions such as HUD already require their consultants to consider vapor encroachment onto the property in their Phase I investigations.