Environmental due diligence is a critical step in many property transactions, and one of the most common tools used to evaluate environmental risk is the Phase I site assessment. In recent years, the industry standard governing these assessments has been updated with the release of ASTM E1527-21, which introduced several important changes to how environmental professionals conduct and document Phase I Environmental Site Assessments.
As of February 13, 2024, the U.S. Environmental Protection Agency requires that Phase I Environmental Site Assessments conducted to meet the All Appropriate Inquiries (AAI) rule follow the updated ASTM E1527 standard. These updates were designed to improve consistency, strengthen historical research requirements, and provide clearer guidance for identifying environmental risks associated with a property.
Key Updates to ASTM E1527
One of the most notable updates in ASTM E1527 is the expanded requirement for historical research. Environmental professionals conducting a Phase I site assessment must now review four key historical sources when available: aerial photographs, fire insurance maps (commonly known as Sanborn maps), historical city directories, and topographic maps. These records help identify past site activities that may have involved hazardous substances or petroleum products. A more thorough historical review improves the likelihood of identifying potential contamination concerns that may affect a property.
The updated ASTM E1527 standard also places greater emphasis on evaluating adjoining properties. Environmental professionals are expected to review historical uses of neighboring properties to determine whether off-site activities could have created contamination risks that may impact the subject property. This change reflects the fact that environmental contamination often migrates beyond property boundaries.
ASTM1527 and Environmental Conditions
Another important update involves clearer definitions for key environmental conditions. ASTM E1527 now provides more precise guidance for identifying and classifying Recognized Environmental Conditions (RECs), Historical Recognized Environmental Conditions (HRECs), and Controlled Recognized Environmental Conditions (CRECs). These definitions help ensure that findings in a Phase I site assessment are reported consistently and interpreted correctly by property owners, lenders, and regulators.
The revised standard also clarifies how environmental professionals should identify and document data gaps. If important information is unavailable during the assessment, the report must indicate whether the missing data affects the environmental professional’s ability to evaluate potential contamination.
Finally, ASTM E1527 reinforces the timeline for report validity. A Phase I Environmental Site Assessment has a 180-day shelf life, which begins when the first assessment activity (such as records review, site reconnaissance or interviews) is conducted. If the report becomes outdated, certain components may need to be updated before the assessment can be relied upon in a property transaction.
How to Identify Your Risks and Maintain Compliance with ASTM E1527
Conversion Technology, Inc. (CTI) has extensive experience performing environmental assessments and supporting clients through regulatory due diligence requirements. The CTI team conducts thorough Phase I site assessment investigations in accordance with the current ASTM E1527 standard, helping organizations identify environmental risks and maintain compliance during property transactions and development projects.