Recommendations in a Phase I report

The standard does not require recommendations. It asks for something different, with a should: the environmental professional's opinion on additional appropriate investigation. Whether recommendations go in the report is settled between the user and the professional in the terms of engagement.

What the standard requires

Recommendations are not required. The practice does not require them. It says the user should consider whether it wants recommendations for more inquiries or other services, and calls them an additional service that may help the user's analysis of the landowner liability protections or of business environmental risks (E1527-21, 12.9).
Only if the engagement says so. A recommendation for Phase II testing or for other assessment work is one of the additional services the user and the environmental professional may contract for. The standard puts such services beyond the scope of the practice, and says they should be in the report only if the terms of engagement specify it (E1527-21, 12.10).
The opinion on additional investigation. The professional should give an opinion on additional appropriate investigation, if any, to detect hazardous substances or petroleum products. An assessment that includes such an opinion is not made incomplete by it, and the opinion is not meant as a requirement to include recommendations for Phase II or other assessment work (E1527-21, 12.8).
The difference between the two. A note in the standard draws the line: the opinion states that more investigation may be appropriate, while a recommendation sets out a particular course of action, and that lies outside the practice's scope (E1527-21, 12.8, Note 6).
Significant data gaps. Where there is one, the professional should discuss whether more information would likely help in deciding if a recognized environmental condition (REC) or a controlled REC exists. That comment is not meant as a requirement to include recommendations either (E1527-21, 12.6.2).
Additions are listed. All additions shall be listed (E1527-21, 12.11).
No sampling. The practice includes no testing or sampling of materials (E1527-21, 7.4).
In the appendixes. The standard's appendixes are nonmandatory. The suggested report format places recommendations, if requested, with the Conclusions and in the executive summary (E1527-21, X5.1.4, X5.9). The legal background appendix says a court weighing continuing obligations may read the professional's recommendations (E1527-21, X1.5.5).

What the federal rule says

The rule does not use the word recommendation. It asks for an opinion:

The inquiry of the environmental professional should include an opinion regarding additional appropriate investigation, if any.

40 CFR 312.31(b)

And it allows sampling as a way to fill a data gap:

Sampling and analysis may be conducted to develop information to address data gaps.

40 CFR 312.20(g)

How it is written

The opinion on additional investigation says whether more investigation may be appropriate to detect hazardous substances or petroleum products, and it stops short of a course of action (E1527-21, 12.8, Note 6). Section 12.8 does not name the part of the report that holds it.

A recommendation, where the engagement calls for one, is an additional service. It is written apart from the opinion and tied to the terms of engagement that call for it; all additions shall be listed (E1527-21, 12.10, 12.11).

Who decides: the standard leaves it to the user to consider whether recommendations are wanted, and to the terms of engagement to say so (E1527-21, 12.9, 12.10).

Example, with the facts in brackets:

Opinion on additional investigation: in the environmental professional's opinion, additional investigation [may / may not] be appropriate to find out whether [hazardous substances or petroleum products] are present at [the location], in connection with [the finding]. This is an opinion under the practice. It is not a recommendation of a course of action.

Example, with the facts in brackets:

Recommendations. These are an additional service beyond the scope of ASTM E1527-21, provided under [the terms of engagement, by date or section]. For [the finding]: [the recommended course of action].

What a reviewer checks

Does the report give the professional's opinion on additional appropriate investigation, if any (E1527-21, 12.8)?
If the report holds recommendations, does it show that the terms of engagement specify them (E1527-21, 12.10)?
Are all additions listed (E1527-21, 12.11)?
For each significant data gap, does the report discuss whether more information would likely help (E1527-21, 12.6.2)?

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.