News and Events

Welcome to our newsroom! Here you will find the latest information about our company, projects and people. Browse articles published by our engineers and scientists in national publications and conference proceedings, view our press releases and read through news coverage of Terracon.

If you are a member of the media, you may contact our media relations representative at

All News and Events

Changing of the Season: Phase I Environmental Site Assessment Practice Changes Coming in November

FallThe long-awaited ASTM E1527-13 Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process is nearly upon us, with an anticipated publication by ASTM in the first couple of days in November. As with the changing of the seasons, some find the changes refreshing, while others prefer no change at all. Terracon has been involved with the ASTM E1527 Committee and provides the following summary of the changes that will be coming.

Overall, these changes to ASTM E1527-13 are relatively minor and consist mainly of clarifications that make the Standard more consistent with CERCLA’s All Appropriate Inquiries (AAI) rule. The minor changes include some revised language (e.g., changing “All Appropriate Inquiry” to “All Appropriate Inquiries;” updating the Objectives language for clarity; adding surface water and soil vapor to the Activity and Use Limitations language for clarification), new definitions (e.g., release, environment, migrate/migration, and a standalone de minimis definition), and updates to the User Questionnaire and User Responsibilities language.

The more substantial changes to the Standard include the following:

Regulatory File Review

The new ASTM standard indicates that regulatory agency files/records should be reviewed if the property or adjoining property is identified on one or more of the standard environmental records’ sources.

REC Definition

The definition of Recognized Environmental Condition (REC) was updated to include the newly defined terms and clarifies that a de minimis condition is not a REC.

HREC Definition

The definition of Historical Recognized Environmental Condition (HREC) has been clarified to include any past release that has been addressed to unrestricted land use standards without subjecting the property to any required controls.

New CREC Definition

A new term/definition was added for Controlled Recognized Environmental Condition (CREC). A CREC is defined as a release that has been addressed to the satisfaction of the applicable regulatory agency with contaminants of concern allowed to remain in place subject to the implementation of required controls (e.g., property use limitations, groundwater use restrictions, institutional controls or engineering controls). A CREC must be identified as a REC in the findings section of the ESA report.

Vapor Pathway

The change that has received the most attention is the addition of the vapor pathway to definitions in the Standard. Contaminants migrate or move along pathways (e.g., in soil, groundwater, surface water, or soil vapor). To evaluate possible impacts to properties with regard to contaminants migrating onto the property, all of the pathways need to be considered. While this concept is not new, its addition to the Standard has caused some concern among users of Phase I ESAs. However, Terracon believes that evaluation of the vapor pathway is similar to evaluation of the soil or groundwater pathways, and that there will be few instances when the vapor pathway is the only complete pathway resulting in a REC (e.g., the soil and/or groundwater on site are not impacted). Thus, there are a few situations in which a REC would be identified that would not have been identified following the current Standard (ASTM E1527-05). In ASTM E1527-13 it is clear that the use of ASTM E2600-10 (Vapor Encroachment Screening Guidance) is not required. While Terracon does not anticipate a significant increase in RECs on properties due to the addition of the vapor pathway, we have seen an increase in activity associated with vapors because the vapor pathway has gained greater attention by regulators and clients over recent years. States have increasingly adopted their own vapor pathway guidance and the EPA is closer to finalizing their vapor guidance documents, which could further increase activity in this area. The result will likely be seen as an increase in vapor sampling and evaluation at the Phase II Site Investigation phase of projects to evaluate whether the vapor pathway is complete, just as Phase IIs currently evaluate the soil and groundwater pathways.

So, what does this mean to you? Let’s take a few examples and run them through the process.

Example #1 (HREC): A site investigated and remediated to an unrestricted residential use standard without any controls under the state’s voluntary cleanup program would qualify as an HREC.

Example #2 (CREC or REC): A site investigated and remediated under the state’s voluntary cleanup program to allow unrestricted residential use at the surface, but with contaminants of concern remaining at depth at concentrations greater than the residential standard, would qualify as a CREC. This is because there are implied restrictions on the use of the site, restricting access to or use of the deeper impacted soils. Redevelopment of the site could change this conclusion if the deeper soils were encountered or new development is placed in closer proximity to the soils. If future anticipated development of the site were to put residential structures with basements in close proximity to the deeper impacts, based on the results, it would be considered a REC.

Example #3 (CREC or REC): A site zoned for industrial use that has been remediated to commercial standards to the satisfaction of the regulatory authority, which has issued a No Further Action (NFA) letter for the site with no use restrictions or controls noted in the NFA letter would qualify as a CREC or REC. Although no use restrictions or other controls were documented by the regulatory agency, since the property was remediated to commercial standards, there is an implied control on the site because the site cannot be redeveloped and used for an unrestricted residential use. Accordingly, this would be considered a CREC and a REC in the report. Assuming that the intended future use of the site is to remain commercial/industrial, no further investigation would be warranted. However, if the future intended use of the property is residential, additional investigation and/or remediation would be required to achieve a residential use for the site.

Example #4 (REC with vapor consideration): A site adjoining a gas station that had a release with a shallow groundwater plume identified extending onto the site with concentrations exceeding commercial groundwater standards would qualify as an REC with vapor consideration. Under both ASTM E1527-05 and ASTM E1527-13, the groundwater plume would be considered a REC based on the known release and impacts to the site. What’s new in ASTM E1527-13 is that because the plume is gasoline, the vapor pathway also needs to be considered since volatile chemicals can migrate from the groundwater plume (e.g. vapor encroachment). The REC already exists because of the groundwater, but now it may be an REC because of both the groundwater pathway and the vapor pathway. In addition, if buildings are located above the groundwater plume, or if intended future redevelopment of the site will put buildings above the groundwater plume, then the potential for vapor intrusion (e.g.,vapors getting into on-site structures) needs to be considered.

Should you have questions, please do not hesitate to contact us.