Prior Phase I report on the subject property

An earlier Phase I report on the subject property turns up. The standard lets its information be used on conditions. How much can be used, and what an earlier conclusion counts for, depends on four things: how old the earlier work is, whether it was done to the practice, what has changed since, and whether any of it is known to be wrong.

What the answer turns on

How old the earlier work is. An assessment that meets the practice is presumed viable when conducted within 180 days before the date of acquisition, or of the intended transaction where there is no acquisition (E1527-21, 4.6.1). One whose information was collected or updated within a year before that date may be used if five parts were done or updated within the 180 days: the owner, operator and occupant interviews; the search for recorded environmental cleanup liens, which is the user's task; the government records review; the visual inspections of the subject property and adjoining properties; and the professional's declaration (E1527-21, 4.6.2). The dates that count are those of the parts, not the date on the report (E1527-21, 4.6.3). Within that period, a user other than the one it was prepared for must also meet the user's responsibilities (E1527-21, 4.6.4).
Whether it was done to the practice. Subject to that updating, information from a prior assessment, one performed more than a year before that date included, may be used only if the procedures that produced it meet or exceed the requirements of the present practice (E1527-21, 4.7, 4.7.1). Historical resources obtained from it may be reviewed if legible copies are appended to it and the professional independently determines that they meet the objective and the requirements of the historical research (E1527-21, 8.4). People interviewed for a prior assessment consistent with the practice need not be asked again about what they said then, but should be asked what they have learned since, or others asked about conditions since (E1527-21, 10.5.3, 11.6).
What has changed since. Prior information may not be used unless conditions likely to affect recognized environmental conditions (RECs) are investigated afresh, and more work may be needed to record what may have changed materially since (E1527-21, 4.7.1). What a prior assessment reports of its site visit may guide the new one but is not to be relied on as showing current conditions (E1527-21, 9.3). A release an earlier report treated as a historical REC or a controlled REC may no longer be one where new conditions or information are identified. Those include a change in regulatory criteria, a migration pathway not known or evaluated before, and for a controlled REC a change of use (E1527-21, 3.2.17.1, 3.2.39.1).
Whether any of it is known to be wrong. If the user or the professional actually knows that information being used from a prior assessment is inaccurate, or other information makes that obvious, it may not be used (E1527-21, 4.8). Short of that, with the steps above followed, the professional may take information provided as given, and reviews all of it (E1527-21, 7.5.2, 7.5.2.1). The standard says an assessment is judged on the reasonableness of the judgments made at the time, and that a later assessment should not be the measure of an earlier one on hindsight, new information or newer techniques (E1527-21, 4.5.4). The professional reviews and interprets the information behind the new report's findings, opinions and conclusions (E1527-21, 7.5.1).

The records that bear on it

The earlier report. Before the site visit the owner, key site manager and user are asked whether environmental site assessment reports exist and for copies (E1527-21, 10.8, 10.8.1). Read it for the date of each part, the sources it checked and the historical resources appended (E1527-21, 4.6.1, 8.1.9, 8.4).
The right to use it. The practice gives no right to use or rely on a prior assessment and puts the contracts among users and professionals outside its scope (E1527-21, 4.7.1, 4.7.2, 4.9). Its nonmandatory legal background appendix reports one court finding that a person a report was not addressed to may not use it, where no reliance letter or other document tied the two, and notes that such orders have limited precedential value (E1527-21, X1.6.5, footnote 199).

What the federal rule says

The inquiry rule lets all appropriate inquiries include an inquiry previously conducted by or for the party now responsible for them, on conditions (40 CFR 312.20(c)). One of them:

Such information was collected or updated within one year prior to the date of acquisition of the subject property;

40 CFR 312.20(c)(2), edition revised as of July 1, 2025

A report prepared by or for other persons can be included if it meets the rule's objectives and performance factors, and if the party seeking to use it reviews the information, makes the rule's additional inquiries and updates the inquiries as necessary (40 CFR 312.20(d)).

The standard speaks of information in assessments more than a year old (E1527-21, 4.7, 4.7.1); the rule's condition is the one-year paragraph quoted. The rule's periods run to the date of acquisition (40 CFR 312.20(a), (b)); where there is none, as in a lease or refinance, the standard uses the date of the intended transaction (E1527-21, 4.6.1). The rule provides that the standard's procedures may be used to comply with 40 CFR 312.23 through 312.31 (40 CFR 312.11(a)).

How it is written up

The report documents each source checked (E1527-21, 8.1.9).

Where the professional concludes differently from the earlier report, the opinion gives the reasons why a finding does or does not fall in each class it pertains to (E1527-21, 12.6). For a release the earlier report treated as historical or controlled, the Findings and Opinions give the rationale for whether it is one now (E1527-21, 3.2.17.1, 3.2.39.1). The standard has no step for reconciling the two reports. Where the professional concludes hazardous substances or petroleum products are present or likely present at the subject property owing to a release, the opinion gives the grounds. Unless judged a de minimis condition or a historical REC, the REC is listed in the Conclusions, and the professional should give an opinion on additional investigation, if any (E1527-21, 3.2.20, 3.2.39, 12.7, 12.8).

An interview with the key site manager, or observation of part of the subject property on the site visit, may be what cannot be had. Required information that good faith efforts could not obtain is a data gap, significant if it affects the ability to identify a REC: named in the Findings with the sources consulted, discussed in the Opinions and listed in the Conclusions (E1527-21, 3.2.19, 3.2.78, 12.5.1, 12.6.2, 12.7).

This page is general reference for environmental professionals. It does not classify any property. ASTM E1527-21 is the standard and is not reproduced here; the judgment of the environmental professional on the facts governs.