ASTM E1527-21: REC Review and Phase I Timing

ASTM E1527-21 provides a framework for Phase I Environmental Site Assessments. This guide focuses on timing and questions to bring to the Environmental Professional reviewing a report. It does not replace the standard or a project-specific assessment.

EPA recognizes E1527-21 as a way to satisfy All Appropriate Inquiries (AAI). AAI is one requirement for certain CERCLA liability protections; eligibility also depends on other requirements and continuing obligations. See EPA’s AAI overview.

Putting the standard into a report-writing workflow? Explore FlipType’s AI Phase I ESA report-writing software, view an illustrative draft excerpt, or book a software demo. Professional review and final sign-off remain with your team.

Phase I ESA timing: count backward from acquisition

Under 40 CFR 312.20, AAI must be conducted within the year before acquisition. Five components must be conducted or updated within the preceding 180 days:

• Interviews with past and present owners, operators, and occupants.
• Searches for recorded environmental cleanup liens.
• Review of federal, tribal, state, and local government records.
• Visual inspections of the property and adjoining properties.
• The Environmental Professional’s declaration.

These windows do not mean the final 180 days of a year measured from report completion. Previously collected information must also be evaluated and updated for relevant changes under the rule.

The ASTM publisher’s overview, sections 4.6–4.7, explains component dates and use of prior assessments. A report’s cover date is not the basis for checking component age. For transactions without acquisition, such as a lease or refinance, the standard addresses the intended transaction date.

REC review: consider evidence about the subject property

The publisher’s scope summary includes actual or likely presence associated with releases, as well as conditions presenting a material threat of a future release. Confirmed contamination is not the only basis for considering a REC. An off-site release can matter when the evidence supports likely presence at the subject property; proximity alone does not establish that conclusion.

Ask the Environmental Professional to explain the evidence connecting a nearby release to the property being assessed. Useful review questions include which records support the opinion, what migration pathways were considered, and which uncertainties remain. See 40 CFR 312.20(e)(1)(vii) on nearby properties.

HREC and CREC: review the closure evidence

A historical closure letter should prompt review of what was addressed, the criteria applied, and any continuing conditions. Avoid treating “closed,” “no further action,” or “residual contamination” as a complete classification decision.

For an HREC or CREC determination, ask the Environmental Professional:

• Does the evidence support unrestricted use, or does the closure depend on controls or limitations?
• Which records establish the closure conditions and any continuing obligations?
• Have current criteria or new information changed the assessment?
• How does the conclusion follow from the applicable E1527-21 definition?

Use the standard’s full definitions for the final classification. A missing document is a reason to investigate and explain uncertainty, not a stand-alone rule that automatically assigns a REC. Similarly, a change in regulatory criteria calls for reassessment rather than an automatic label based only on the age of a closure.

Data gaps and report organization

Identify gaps affecting the ability to identify releases or threatened releases, the sources consulted to address them, and their significance. Explain how significant gaps affect the assessment. See 40 CFR 312.20(g) and the reporting requirements in section 312.21(c)(2).

Do not confuse a condition’s classification with its location in the report. EPA’s reporting guidance expressly includes HRECs and de minimis conditions among possible findings. Its suggested report structure is not itself a regulatory requirement. The report must still satisfy the applicable documentation requirements and the standard used for the assessment.

PFAS: distinguish the substances and the scope

EPA designated PFOA and PFOS, including their salts and structural isomers, as CERCLA hazardous substances. It is therefore inaccurate to describe all PFAS as categorically outside a Phase I assessment’s hazardous-substance scope. The designation concerns these substances, not the entire PFAS class. See EPA’s designation page.

For a particular project, confirm the substances being evaluated, applicable federal and state requirements, and any additional services agreed with the user. A reference to “PFAS” without that context can obscure what was actually considered.

Before relying on a report

• Check the acquisition or intended transaction date against the dates of the underlying components.
• Read the evidence and reasoning behind each classification, including closure records and controls.
• Check that limitations and significant data gaps are explained.
• Confirm project scope and any responsibilities retained by the user.

For the reporting workflow, see our guide to traceability in AI-assisted Phase I reporting. Source references make review easier, but the Environmental Professional must evaluate the evidence and conclusions.