The ASTM Standard for Phase I Environmental Site Assessments (E1527) is evaluated every eight years.

The Standard was updated with input from industry professionals, including AEI Consultants’ team members, with the goal of continuing to improve the standards that guide Phase I Environmental Site Assessment (ESA) reporting.

There were many updates, but the most significant change relating to AEI’s work is the new standard for historical records review section.

It has been restructured and updated to clarify that the E1527-21 Standard for Phase I ESAs requires additional historical research to include the subject property and the adjoining properties. 


  • “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.” – ASTM

What are other notable changes?

  • 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/HREC/CREC 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.
  • 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 as resources with the Standard: including a revised legal appendix; new REC/HREC/CREC guidance; revised report outline; and updated discussion of business environmental risks including emerging contaminants.

Anything else to know?

Yes, ASTM E1528-14 (Environmental Transaction Screen) is also in the process of being revised (likely to be published in 2022.) The Transaction Screen Questionnaire will be significantly revised.

We look forward to continuing to provide you with high-quality services and reports that are always in alignment with the most up-to-date standards. Please reach out to us with any questions at