ASTM E1527-21 is the current standard practice for Phase I Environmental Site Assessments in the United States. EPA issued a final rule on December 15, 2022 recognizing it as a way to satisfy the All Appropriate Inquiries rule, effective February 13, 2023. EPA then removed references to the older E1527-13 standard as of February 13, 2024, so new Phase I reports relied on for AAI should follow E1527-21.
The main changes
A clearer definition of a REC
The 2021 revision restructured the definition of a recognized environmental condition into three parts: the presence of hazardous substances or petroleum due to a release, the likely presence due to a release or likely release, and conditions that pose a material threat of a future release. It also explains what "likely" means: more probable than not, based on the evidence available.
CRECs and HRECs
The standard clarifies how to classify past releases. A historical REC (HREC) has been addressed to unrestricted-use standards; a controlled REC (CREC) has been addressed but relies on controls such as deed restrictions or engineering controls. The EP now has to explain the reasoning behind each classification, and an appendix provides logic flowcharts.
More thorough historical research
Historical research now explicitly extends to adjoining properties, and the standard expects specific standard historical sources, such as aerial photographs, fire insurance maps, city directories and topographic maps, to be reviewed where reasonably ascertainable.
Report viability is easier to track
Reports must list the dates of key components, including interviews, the lien search, the records review, the site visit and the EP declaration. That makes it clear when the report's 180-day and one-year windows run out. See how long a Phase I is valid.
Significant data gaps
When missing information affects the EP's ability to identify RECs, the report must say so and explain the effect.
Emerging contaminants
Substances such as PFAS are treated as a non-scope consideration unless they're regulated as CERCLA hazardous substances. In 2024 EPA designated PFOA and PFOS as CERCLA hazardous substances, so many Environmental Professionals now consider them where site history suggests they could be present. Ask your EP how they're handled on your property.
What this means for you
- Make sure any new Phase I states that it conforms to ASTM E1527-21.
- If you're relying on an older E1527-13 report, ask whether it needs to be updated or redone for your transaction.
- Expect a clearer explanation of findings, which makes it easier for lenders to act on the report.
Every Breeze Phase I conforms to ASTM E1527-21 and AAI, and is backed by our money-back guarantee.
Frequently asked questions
Is ASTM E1527-13 still acceptable?
EPA removed references to E1527-13 from the All Appropriate Inquiries rule as of February 13, 2024. New Phase I reports relied on for CERCLA defenses should follow E1527-21.
Does ASTM E1527-21 require PFAS testing?
No. A Phase I does not include sampling. PFAS are a non-scope consideration unless regulated as CERCLA hazardous substances; PFOA and PFOS were designated in 2024, so EPs may consider them where relevant.
This article is general information about environmental due diligence and is not legal advice. Requirements can change; confirm specifics with your lender or attorney.
