Likely release and likely presence

The second part of the definition of a recognized environmental condition (REC) turns twice on one word: the likely presence at the subject property of hazardous substances or petroleum products, owing to a release or a likely release (E1527-21, 3.2.73). Neither has to be proved. How the two judgments are made and written depends on four things: what the standard says likely means, who judges it, which of the two judgments is open, and what each is weighed on.

What the answer turns on

What likely means. For this definition, likely is short of certain and short of proved. It is what a reasonable observer would expect or believe, going on the environmental professional's logic or experience or on the available evidence, as the report states them in support of its opinions (E1527-21, 3.2.73.1). The standard puts no number on it.
Who judges it. The environmental professional evaluates the lines of evidence on professional judgment, and reviews and interprets the information behind the findings, opinions and conclusions (E1527-21, 7.3.1, 7.5.1). The standard's appendixes are nonmandatory. Appendix X4 calls the opinion that a release is likely, and the opinion that presence is likely, subjective, and says each should rest on the professional's experience, the site visit and other reasonably ascertainable information (E1527-21, X4.1). An assessment is to be judged on the reasonableness of the judgments made at the time, not on hindsight (E1527-21, 4.5.4).
Which judgment is open. By Appendix X4, where a release and presence at the subject property are both known, the first part of the definition applies and nothing rests on likelihood. A release known at another property leaves one judgment: likely presence at the subject property. A release that is only likely, on the subject property or off it, takes two judgments together: likely release and likely presence (E1527-21, X4.1).
What each is weighed on. For a likely release, Appendix X4's factors include the features, conditions or operations involving hazardous substances or petroleum products, how long they lasted, and their period. Its note gives petroleum storage, dry cleaning or manufacturing run for a significant period before regulatory controls as possible examples, if the professional believes a release likely (E1527-21, X4.1). For likely presence from a source off the subject property, its factors include where the source lies, the topography, geology and hydrogeology, and other information such as agency data, the database report and prior assessments (E1527-21, X4.1). In the body of the standard, the history of uses is compiled to help weigh the likelihood that past uses led to RECs (E1527-21, 8.3.1). Where the site visit points to a likely release at a nearby property that may migrate, the setting is evaluated for whether a REC at the subject property likely results (E1527-21, 9.4.6).

The records that bear on it

History of uses. How long a use ran, and when, come from the history of the subject property and its adjoining properties (E1527-21, 8.3.8, 8.3.9).
Government records. Each listing of the subject property, or of a site within its search distance, gets the professional's judgment on its significance. The standard's sample of such a statement is one that no listed site is likely to have releases able to migrate to the subject property, with the exceptions named (E1527-21, 8.1.10).
Physical setting. Groundwater, geology and soil maps are sought when migration to the subject property is likely and local practice is to obtain them (E1527-21, 8.2.1).
No sampling. The practice includes no sampling, so likely is judged on the records, the site visit and the interviews (E1527-21, 7.4).

What the federal rule says

The rule asks for the professional's opinion in these terms:

An opinion as to whether the inquiry has identified conditions indicative of releases or threatened releases of hazardous substances

40 CFR 312.21(c)(1)

And it defines the environmental professional as

a person who possesses sufficient specific education, training, and experience necessary to exercise professional judgment to develop opinions and conclusions regarding conditions indicative of releases or threatened releases

40 CFR 312.10

How it is written up

The Opinions give the professional's reasoning on the likely impact to the subject property of what the Findings list (E1527-21, 12.6). Because likely is measured by grounds stated in the report, each likely judgment names its grounds, and findings, opinions and conclusions are supported by documentation (E1527-21, 3.2.73.1, 12.2).

Where two judgments are needed, the opinion takes them in turn: why a release is likely, from the use, its years and its period; then why presence at the subject property is likely, from position, setting and data. Where a release at another property is known, only the second is argued. 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 (E1527-21, 3.2.20, 3.2.39, 12.7, 12.8).

Where the professional concludes that a release, or presence at the subject property, is not likely, the opinion on a finding says which and why (E1527-21, 12.6).

Historical sources for the years in question, or an interview with the key site manager, 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.