For the first time in ASTM E1527-13 (E1527-13),¹ ASTM required the environmental professional (ENV Pro) to actively conduct a vapor survey.²  But it is difficult to explain how an ENV Pro should conduct a vapor survey, resulting in potentially deficient Phase I Environmental Site Assessments (Phase I ESAs) being provided to entities purchasing and investing in real property.  This article attempts to explain the issues faced by ENV Pros as they attempt to meet the requirements of E1527-13 and the All Appropriate Inquires important to real estate purchasers by performing a non-invasive review of the property at issue and the files and databases that (allegedly) contain all there is to know about the property.

History of Vapor Issues
Vapor issues first came into focus in the 1970s and 1980s when regulators expressed concern about radon exposure.  This concern quickly spread to the general public, bringing about a profitable industry to sell various types of equipment designed to control radon exposure in private homes, apartments and other multi-family structures.  But, when the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) was passed there was little concern about vapor.  The radon issues that had been identified by the regulatory agencies did not fall under CERCLA because the radon gas was the result of naturally occurring degradation processes, not the result of a spill, release, disposal or other man-made trigger.  Thus, investigations and remediation in the early days of CERCLA were primarily concerned with hazardous liquid and solid waste, not vapor, and not soil vapor or other "man-made" vapor underground.
 
In late 2002, the U.S. Environmental Protection Agency (EPA) published its first guidance containing information relating to vapor intrusion assessments.  Although a "User's Guide for Evaluating Subsurface Vapor Intrusion into Buildings" was published under an EPA contract in February 2004, the 2002 EPA guidance remained in draft format for more than a dozen years.³ Finally, in 2015, EPA issued its "OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air" (2015 Guide).⁴  The 2015 Guide contained a massive amount of information relating how to assess and mitigate the vapor pathway to indoor air.  But the 2015 Guide offered little help to the ENV Pro as to evaluating potential vapor migration in a Phase I ESA setting, so the user of the Phase I ESA could utilize the Phase I ESA as part of the user's All Appropriate Inquiries process.
 
Current Day Practices and Problems
Despite vapor coverage in E1527-13 and vapor issues being raised by many state environmental agencies, in addition to EPA,⁵ there frequently is no mention in Phase I ESAs of any consideration relating to potential vapor migration issues, including vapor migration into existing buildings.  Not all vapor issues fall under CERCLA, but those associated with a release, spill, disposal activities or other issues not naturally occurring fall under CERCLA nearly all the time.  Thus, purchasers of real property are constantly considering how to utilize the Phase I ESA to its benefit as part of the All Appropriate Inquires process.
 
Like many other situations, the entity that should benefit from the Phase I ESA and the All Appropriate Inquires process needs to be diligent as the process moves forward.  The purchaser should remind its legal counsel as well as its ENV Pro that the purchaser intends to use the results of the Phase I ESA as part of its All Appropriate Inquiry.  If the purchaser has the opportunity to review a draft of the Phase I ESA, it should make certain the ENV Pro has made specific reference to a vapor assessment in the Phase I ESA Report.  The ENV Pro should describe not only his or her findings that there is no vapor risk because there are no known spills or releases in close proximity that could impact the property at issue, but the ENV Pro should also describe the process used to determine the users of the property being studied have not caused a vapor issue.
 
Where there is a known issue that could cause vapor migration in the area, the ENV Pro must do more than just mention the ENV Pro has seen the issue in an EDR report.⁶  The ENV Pro may conduct an actual file review to gain a more complete understanding of the potential for migrating vapor to impact the property being studied.  Additionally, the ENV Pro may have to consider whether, in the years ahead, known migrating vapor might impact the property being studied, even though at present the vapor may not be impacting the property at all or at concentrations below action levels.  But, as actionable concentrations are reduced as more is understood about the risk some chemicals present to human health and the environment, what was not a risk today may become a risk tomorrow…

^{1 Standard Practice for Environmental Site Assessments: Phase I Environmental Sites Assessment Process.  Prior to ASTM issuing E1527-13, ASTM's E1527-05 had been in effect.  However, in late 2013, EPA issued a rule that allowed E1527-13 to be used in All Appropriate Inquires.  See https://www.federalregister.gov/documents/2013/12/30/2013-31112/amendment-to-standards-and-practices-for-all-appropriate-inquiries-under-cercla.  In this same rule, EPA mentioned its intent to propose a new rule that would delete reference to E1527-05 in the near future.
2 See ASTM E1527-13, §§ 3.2.2 and 3.2.56 to see how vapor fits into several of the definitions utilized by ASTM.  See also ASTM's legal determinations at X.1.1.1.2(4) and non-scope at X5.8.  E1527-13 can be viewed at https://elibrary.gsfc.nasa.gov/assets/doclibBidder/tech_docs/ASTM%20E1527-13.pdf.
3 Although not used exclusively in this manner, "vapor migration" will typically be an in-scope item for a Phase I ESA, but "vapor intrusion" will normally be considered an out-of-scope item in a Phase I ESA.  Vapor intrusion, when not "man made," does not typically fall under CERCLA, but where there is "vapor migration" from a source that is arguably "man made," then CERCLA will typically come into play, whether or not vapor intrusion is involved.
4 See https://www.epa.gov/sites/production/files/2015-09/documents/oswer-vapor-intrusion-technical-guide-final.pdf.  A related guide (similar to a typical EPA fact sheet) can be accessed at https://www.epa.gov/sites/production/files/2016-10/documents/factsheet.pdf.
5 See EPA's Vapor Intrusion site at https://www.epa.gov/vaporintrusion.
6 Most ENV Pros recognize and understand that the EDR database, while robust in many ways, does not always identify all the environmental issues in a given locale}