Scoping a Phase II

Under ASTM E1903-19 the scope of a Phase II follows from what the user needs to know (E1903-19, 1.3). The user and the Phase II Assessor consult to set the objectives and the scope (E1903-19, 1.1.1), and the scope of the work must be defined against those objectives (E1903-19, 1.4). The objectives, with the questions the assessment is to answer, must be put in writing as a Statement of Objectives, which must sit inside a written document such as a proposal, contract, work order or scope of work (E1903-19, 5.1.1).

What the two weigh

Among the factors the standard lists for that consultation (E1903-19, 1.1.1):

which substances have or may have escaped into the environment, and why their presence is a concern;
how those substances behave, and their fate and transport;
which part of the property needs investigating;
the information already in hand;
the confidence needed or wanted in the results, and the sampling and chemical testing it will take to reach it;
any time and resource constraints.

Whatever the scope, the practice requires scientifically sound work toward the stated objectives (E1903-19, 1.1.1).

The Statement of Objectives

The question. The question or questions the Phase II is to answer must be formulated jointly by the Phase II Assessor and the user, with the user's objectives in view; the Phase II Assessor must set out one or more hypotheses for the investigation to confirm or refute, and the questions must appear in the written Statement of Objectives (E1903-19, 6.4.1, 7.1). The objectives may also fix a threshold of concern, or how confident the user wants the conclusions to be (E1903-19, 7.1).
What each side brings. While the statement is drafted, the Phase II Assessor should explain the process so the user can decide with knowledge, and the user should hand over what the user knows of and can reasonably get: earlier ESAs and other studies, oral histories of releases or disposal, and detailed knowledge of specialized operations at the property (E1903-19, 5.1.3).
Limits. The statement must identify and describe any limits of schedule, cost or budget, including any limit fixed in advance on the scope, on the number of sampling rounds, or on other activities that bear on scope, schedule or cost (E1903-19, 5.1.2). Both sides must consider whether the limits will keep the Phase II from meeting the practice; if so, the statement must either adapt the objectives to fit them or describe their expected effect (E1903-19, 5.1.2).
In the report. The report must give the final Statement of Objectives word for word in its introduction (E1903-19, 9.2).

The scope of work

Under the standard, the Phase II Assessor shall write out the methods and tasks that will carry the work to the user's objectives (E1903-19, 5.1.4). Another document with the same elements, such as a proposal, may stand in for a formal description (E1903-19, 5.1.4).

The purpose is to gather and evaluate enough information to achieve what the Statement of Objectives sets out (E1903-19, 6.1). The work may take one round or several of planning, carrying out and evaluating, and the practice asks for only as many as the objectives need (E1903-19, 6.3). The general steps of the process must all be taken, each at the level of detail the objectives call for (E1903-19, 6.4). Scope and objectives may both be revisited as the work goes on (E1903-19, 1.3).

Choosing the areas to investigate

Review. The assessor must independently review and evaluate all relevant information that is reasonably ascertainable, including any Phase I report, for completeness, accuracy and adequacy as the basis for the investigation (E1903-19, 7.2). Developing the scope also requires the assessor to judge whether that information can meet the objectives (E1903-19, 1.3.1).
Areas. The Phase II Assessor must select the areas that need investigation for the objectives to be met, and should use professional judgment grounded in the activities, operations and releases that go with the property's past uses (E1903-19, 7.3).
RECs. The Phase II Assessor may designate RECs from a Phase I for investigation as far as the objective needs; not every REC has to be designated, and a condition that was not a REC may be (E1903-19, 7.3.1).
Past operations. The Phase II Assessor must weigh the property's past activities and operations for the potential for releases, or other signs that relevant substances are present or likely present (E1903-19, 7.3.2).
Data gaps. The Phase II Assessor must consider whether data gaps named in a prior Phase I should be addressed by sampling and chemical testing, and if so, the area and the media that may be affected must be identified (E1903-19, 7.3.3).
All of them. The Phase II Assessor must designate every area where substances that matter to the objectives are present or likely present and that must be investigated to meet them (E1903-19, 7.3.4).

A likely release area, where the Phase II Assessor judges that a release likely first put target analytes into environmental media, can include Phase I RECs but is not limited to them (E1903-19, 3.1.27).

How much confidence the user needs

The confidence the user wants shapes both the scope and the evaluation of the data: detailed conclusions held with high confidence may need more testing and more rounds; general conclusions may need less of both (E1903-19, 1.4.1). The standard does not generally call for an exhaustive assessment, and once target analytes are confirmed, how far to go further depends on the confidence required and the uncertainty acceptable for the objectives (E1903-19, 4.2.2).

Constraints

Besides the limits the statement must record (E1903-19, 5.1.2), gaps or defects in the information behind the objectives and scope can weaken a Phase II, such as a site history or prior assessment that could not be obtained despite both sides' efforts (E1903-19, 4.2.1.2). What the standard's nonmandatory appendix suggests on limits in the contract is covered in Contracting a Phase II.

This page is general reference for environmental professionals. It does not assess any property. ASTM E1903-19 is the standard and is not reproduced here; the judgment of the Phase II Assessor on the facts governs.