Standard Practice for Environmental Site Assessments Revised

ASTM International’s environmental assessment, risk management and corrective action committee (E50) has revised its standard practice for Phase I environmental site assessments (E1527).

“Phase I environmental site assessments (ESAs) aid in the underwriting of mortgage loans and inform prudent risk management and business decision-making,” says Jim Bartlett, senior vice president with Bureau Veritas and ASTM committee officer. “Nearly all Phase I ESAs are performed in accordance with this ASTM standard practice.”

According to Bartlett, Phase I ESA’s facilitate commercial property transfers that satisfy the U.S. Environmental Protection Agency (EPA) All Appropriate Inquiries Rule, as defined by the US federal Superfund law (CERCLA), and 40 CFR Part 312.

First published in 1993 to define "good commercial and customary practice" for conducting ESAs, this latest revision was approved Nov. 1, 2021, and represents over three years of ongoing collaboration and consensus-building by more than 150 industry professionals.

Substantive changes that all environmental professionals, ESA users, and other stakeholders should be aware of include:

  • Key terminology revisions: The terms “Recognized Environmental Condition” (REC); “Controlled Recognized Environmental Condition” (CREC); and “Historical Recognized Environmental Condition (HREC) have been strengthened to reduce misclassifications of known or likely hazardous material and petroleum product releases affecting subject properties. The revisions are further supported by a new appendix that provides guidance on the REC/HERC/CERC decision process, a flow chart, and representative examples of each.
  • New definitions: The terms “Property Use Limitation” (PUL); and “Significant data gap” have been formally defined to provide important clarification of existing concepts.
  • The historical records review section has been restructured and updated to reflect good commercial and customary practice. The revisions clarify subject and adjoining property identification, use, and research objectives; and new parameters have been established for the use of standard historical sources.
  • Detailed site reconnaissance requirements have been added to reinforce existing good commercial and customary practice.
  • Revised report requirements have been added to strengthen the deliverable, including consistent use of the term “subject property”; identification of RECs, CRECs, and significant data gaps in the Conclusion section; photos of site reconnaissance items; and a site map.
  • Updated appendices: Include an extensively revised legal appendix; new REC/HREC/CREC guidance; revised report outline; and updated discussion of business environmental risks including emerging contaminants.

“The latest revisions reflect a remarkable compilation of inputs from across industry, including a diverse group of users, providers, and other interests,” says Julie Kilgore, ASTM member and chair of the standard’s task group. “This input reflects professional insights, project experiences, and challenges with previous versions of the standard.”

Kilgore notes that Environmental Professionals producing quality deliverables and users familiar with the standard will see minor but important changes in this iteration of the Phase I ESA practice.

Updated ASTM Training Programs on the new standard are available at

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