What a Phase I report must contain

ASTM E1527-21 says what a Phase I report shall hold in its report section and in several other sections. The requirements are listed here in short, with their sections and the handbook pages that cover them.

What the standard requires

Largely in the order of the standard's report section (E1527-21, 12), with what other sections add:

Documentation and records. Findings, opinions and conclusions shall be supported by documentation, in the report or adequately referenced, with reasons for any left out (E1527-21, 1.1.5, 12.2). The report shall document each source checked, explain any adjusted search distance, judge each listing's significance, summarize each file review and its sufficiency (or justify having none for a listed subject or adjoining property), describe the uses identified, reference the historical resources used, and document data failure (E1527-21, 8.1.2.1, 8.1.9, 8.1.10, 8.2.3.1, 8.2.3.2, 8.3.6, 8.3.8, 8.3.9, 8.3.10, 8.5): The records review section of a Phase I report.
Who and when. The report shall identify the environmental professional and whoever conducted the site reconnaissance and interviews, with the dates (E1527-21, 12.3). The dates of the interviews, government records review, visual inspections and declaration shall be identified, with that of the lien search where the professional made it (E1527-21, 4.6.1): Dates in a Phase I report.
The user. The report shall say whether the user reported information under the user's responsibilities (E1527-21, 7.3.2, 12.3). It shall describe whether the professional received the results of the user's lien and activity and use limitation search, and state the purpose assumed where the user named none (E1527-21, 6.2.3.2, 6.8): User-provided information in a Phase I report.
The site visit. A site plan shall be included, with photographs of what indicates a recognized environmental condition (REC) or a de minimis condition (E1527-21, 12.3). The method of observation and the limitations shall be documented, and each listed feature described or documented as not found (E1527-21, 9.2.1, 9.2.6, 9.4): The site reconnaissance section of a Phase I report.
Interviews. The occupants interviewed shall be identified, with how long each has occupied the property (E1527-21, 10.5.2.4): The interviews section of a Phase I report.
Scope and limits. Every service performed shall be described. Limiting conditions, deletions and deviations shall be listed individually and in detail, and all additions listed (E1527-21, 12.4, 12.11): Limiting conditions and deviations in a Phase I report.
Findings. A Findings section is required; it also identifies significant data gaps (E1527-21, 12.5, 12.5.1): The Findings section of a Phase I report.
Opinions. The professional's opinion and rationale on what the Findings identify shall be included, with a comment on each significant data gap. Identifying a controlled or historical REC shall be reflected in the Findings and Opinions (E1527-21, 12.6, 12.6.1, 12.6.2, 3.2.17.1, 3.2.39.1): The Opinions section of a Phase I report.
Conclusions. A Conclusions section shall list the RECs, controlled ones included, and the significant data gaps, and the report shall carry a closing statement substantially similar to one of two the standard words (E1527-21, 12.7): The Conclusions section of a Phase I report.
Additional investigation. The professional should give an opinion on it; recommendations are not required (E1527-21, 12.8, 12.9): Recommendations in a Phase I report.
References. A references section shall identify the published sources relied on, each annotated so that another party can retrieve it (E1527-21, 12.12).
Signature, statements, appendixes. The responsible professional shall sign. The report shall include the two statements the federal rule requires, and an appendix section (E1527-21, 12.13, 12.14, 12.15): The environmental professional's statement and signature.

What the federal rule says

The rule's own list:

The results of the inquiry by an environmental professional must be documented in a written report that, at a minimum, includes the following:

40 CFR 312.21(c)

Three things follow: the professional's opinion on what the inquiry identified, the data gaps and their significance, and

The qualifications of the environmental professional(s).

40 CFR 312.21(c)(3)

The rule gives its list as a minimum; the standard's longer list has provisions on the same three subjects (E1527-21, 12.5.1, 12.6, 12.6.2, 12.15). The rule says the standard's procedures may be used to comply with its sections 312.23 through 312.31 (40 CFR 312.11); this list is in 312.21.

How it is written

The body of the standard sets no order for the report; it says only that a suggested format is in an appendix (E1527-21, 4.10, 12.1). The standard's appendixes are nonmandatory, and that one says its sections may go elsewhere in the report at the professional's discretion (E1527-21, X5). An executive summary appears only there: The executive summary of a Phase I report.

What the body does fix:

Findings and opinions may share one section (E1527-21, 12.6).
Significant data gaps are identified in the Findings, commented on in the Opinion section and listed in the Conclusions (E1527-21, 12.5.1, 12.6.2, 12.7).
The closing statement names the section that describes exceptions and deletions (E1527-21, 12.7.1, 12.7.2).
The appendix section holds the supporting documentation, and the qualifications of the professional and of others who conducted the site visit or interviews (E1527-21, 12.15).

It does not say where the closing statement, the signature or the two statements sit (E1527-21, 12.7, 12.13, 12.14).

What a reviewer checks

Is there a references section that identifies the published sources relied on (E1527-21, 12.12)?
Is each referenced source annotated well enough for another party to retrieve it (E1527-21, 12.12)?
Is there an appendix section that contains the supporting documentation (E1527-21, 12.15)?

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.