Enlarge this picture Vapors can move through the soils to invade other buildings in a process known as vapor intrusion. The above graphic illustrates how vapors can be transported.

On Nov. 1, 2006, the EPA's new standards^[1] for conducting all appropriate inquiries (AAI) went into effect. These regulations set the standard for conducting Phase I Environmental Site Assessments (ESAs) to meet the test of the so-called "innocent purchaser defense" under the federal Superfund (or CERCLA) program.

The purpose of performing an environmental site assessment (ESA) is that it is intended to allow the user to assert liability protections under Superfund. AAI also is required for many EPA Brownfields Grant recipients, having been promulgated pursuant to the federal Small Business Liability Relief and Revitalization Act, better known as the "Brownfields Act." The AAI regulation references ASTM's E 1527-05 standard of practice^[2] for Phase I ESAs, indicating that it may be used to comply with the requirements of AAI.^[3] AAI and ASTM E 1527-05 establish a standard, minimum baseline that is considered reasonable to provide a user with information about the environmental quality of a property.

However, these procedures have significant differences, the most important being that the AAI regulations include only contaminants that are CERCLA hazardous substances included in the federal Superfund program. As a result, petroleum compounds are explicitly excluded from consideration, although the potential for liability remains in other federal and state petroleum contamination laws and regulations. Therefore, dependence on and compliance with the AAI rules may provide relief from liability with respect to CERCLA, but are not intended to offer protection from exposure with respect to state and federal petroleum pollution statutes and regulations.

Additionally, ASTM has developed a Standard Practice for Assessment of Vapor Intrusion into Structures on Property in Real Estate Transactions^[4] in order to develop a standard procedure to assess vapor intrusion as it relates to property transactions. The intent of this standard practice is to provide a sound, scientific method by which potential exposures that may pose an environmental risk and/or liability are adequately evaluated as part of the property acquisition due diligence process.

The interrelationships between Phase I ESAs and vapor intrusion, and between their respective practice standards, are still new and evolving. In the past, issues that have arisen in the context of conducting Phase I ESAs have been resolved by the needs of the market, the experience of the practitioners, and by the courts.

Ten considerations

Enlarge this picture A tiered approach to evaluating vapor intrusion is illustrated in the table above.

With respect to vapor intrusion, an entirely new dynamic has arisen, that of a co-existing practice standard; this has been interpreted by some as an integrated practice standard, which is not strictly true nor appropriate. Only time and experience will define how these practice standards will interrelate in the real world. Here are 10 considerations and cautions to consider when these practices are implemented.

1. Vapor intrusion as a potential REC is not new. Experienced practitioners always have been aware of the potential for release of organic vapors into a building, causing an indoor air quality issue and degrading the potential safe use of the building. It is receiving greater attention, but has always been a potential consideration.

2. Vapor intrusion is a non-scope item in ASTM E 1527-05. It can be a Phase II activity if the potential for a vapor intrusion issue is identified as a recognized environmental condition (REC) during the Phase I ESA. Then a vapor intrusion screening investigation (at the least) may be recommended as a follow-up Phase II activity. However, there is no implication in ASTM E 2600-08 that a vapor intrusion screen must be prepared as part of a Phase I ESA. The authors of the practice standards are firm on this issue (see the discussions at http://commonground.edrnet.com/Discussions/tabid/1692/view/topics/forumid/394/Default.aspx ).

3. So-called "No Further Action" letters from regulatory agencies should be less than reassuring and cannot necessarily be blithely accepted. Usually, they allow re-openers, i.e. the opportunity for the regulatory agency to revisit the issues related to the site if cleanup thresholds change, the risk associated with contaminants changes, or for other reasons.

4. Vapor intrusion issues can affect any kind of property, depending on the historic land use of the subject site, and/or adjacent or nearby land uses. The concept that undeveloped land, offices or residential properties are unlikely to present RECs has always been a cautionary tale, more so now that awareness of vapor intrusion issues has grown.

5. Vapor intrusion issues do not occur only as a result of CERCLA-listed volatile organics, but obviously also from petroleum products. Remember, the EPA's AAI rule considers only CERCLA hazardous substances and not petroleum compounds; ASTM 1527-05 includes petroleum compounds. Therefore, the practice that is applied at a site not only influences findings relating directly to RECs, but also to potential vapor intrusion issues associated with the source compound underlying the REC. As a result, when reviewing the work prepared by others, the underlying standard of practice that was applied may be critical to the findings (or lack of findings). If the standard of practice was AAI, it may not be sufficient to address site issues or the client's needs.

6.Clients often are inexperienced and uncertain with respect to environmental risk, and look to consultants to assist them in their decision-making. Issues and potential issues related to vapor intrusion only complicate matters. That causes problems for both parties. If the consultant participates in the decision-making regarding the acquisition of a property, or in defining the risk posture of the client, the consultant opens itself to liability with respect to unsatisfactory outcomes. If the client (buyer) depends on the consultant, the implication is that the consultant is qualified to make the technical and business decision, a chancy situation. General or real estate counsel may not be in a better position to intervene.

7. Attorneys often desire technical and scientific certainty for decision-making, as do financial professionals associated with lending institutions. The environment does not allow such assurances. Of course, to the environmental professional, the answer unfortunately always is "maybe!" As a late supervisor of the authors often said: "The environment is not a glass bottom boat;" such answers are not self-evident. A sequence of steps may be necessary, each with its own cost, and the potential buyer must decide whether paying these costs, in increments or in total, is consistent with his risk posture, and the value and need for the property.

8. The differing objectives and risk postures of buyer and lender may result in a difference of opinion as to the potential for, or implications of, a vapor intrusion issue. The competing, subjective opinions of the lender's environmental professional and the buyer's EP can be expected to confuse any decision-making process, although the opinions of the lender's EP likely will prevail, for obvious reasons.

9. If old underground storage tanks (USTs) are present but no historic or current leaking USTs have been identified, what does the environmental professional do with respect to the potential for a REC relating to a vapor intrusion issue? This should be handled by the EP the same way the implications of historic land use are addressed – with the experience and discretion of the EP, on a case-by-case basis, with the rationale explicitly documented in the Phase I report. This is why the experience of the EP is, and always has been, an issue – the philosophy of always recommending a Phase II investigation where there is questionable historic land use may be overkill, and surely does not take the client's risk posture, the nature of the historic land use, future land use, and other considerations into account.

10. Cost – it often starts and ends with cost. Tier 1 vapor intrusion screenings may only cost a few hundred dollars in many instances, but Phase I ESAs are often subject to commodity pricing. Therefore, unless explicitly requested, a Tier 1 screen is unlikely to be suggested as a routine, non-scope item for a Phase I since it may be a selection-killer for the EP. PE