Standard Historical Last Updated: Jan 08, 2020 Track Document
ASTM E1903-11

Standard Practice for Environmental Site Assessments: Phase II Environmental Site Assessment Process

Standard Practice for Environmental Site Assessments: Phase II Environmental Site Assessment Process E1903-11 ASTM|E1903-11|en-US Standard Practice for Environmental Site Assessments: Phase II Environmental Site Assessment Process Standard new BOS Vol. 11.05 Committee E50
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Significance and Use


This practice is intended for use on a voluntary basis by parties who wish to evaluate known releases or likely release areas identified by the user or Phase II Assessor, and/or to assess the presence or likely presence of substances, for legal or business reasons such as those described in 1.2.

This practice is intended to meet the business community's need for a written, practical reference describing a scientifically sound approach to investigating a property to evaluate the presence or likely presence of a substance. It is impossible to generalize about the contexts in which a user may wish to conduct such investigations or the degree of confidence a user may require in the results. In any context, this practice, being rooted in sound scientific methodology, can assist users in achieving an objective and defensible assessment.

This practice does not address the evaluation of business environmental risks in light of data collected through the Phase II ESA process. Such evaluation is a function of site- and transaction-specific variables, and of the users objectives and risk tolerance. This practice contemplates that the Phase II ESA process will be planned and conducted with such variables in mind, and that the user will evaluate legal, business and environmental risks in light of known data relating to the particular site and transaction, and in consultation with legal and business advisors as well as the Phase II Assessor.

Likewise, this practice does not define the threshold levels at which target analytes pose a concern of significance to the user. Users may apply this practice not only in light of applicable regulatory criteria and relevant liability principles, but also to meet self-defined objectives.

If a Phase II ESA conducted in accordance with this practice provides sufficient information from which the Phase II Assessor can conclude, consistent with the scientific method, that the question to be addressed by the assessment (see 6.4.1) has been answered, then further assessment is not warranted to meet the objectives of the assessment.

Use Not Limited to CERCLAThis practice is designed to assist a user in developing information about the environmental condition of the property and has utility for a wide range of target analytes (e.g., including diffuse anthropogenic contamination and naturally occurring substances) and users including those who may have no actual or potential CERCLA concerns.

Site- and Transaction-SpecificThe scope of a Phase II ESA is site-specific and context-specific. The assessment process defined by this practice is intended to generate sound, objective, and defensible information sufficient to satisfy diverse user objectives.

Use by Other PartiesAssumptions and limitations based on the user's objectives will be built into the implementation of this practice. Any party other than the user who seeks to use a Phase II ESA must therefore understand all such assumptions and objectives and independently evaluate whether the earlier assessment meets the needs of such other party. To promote such understanding and evaluation, Section 9 of this practice requires that objectives of a Phase II ESA be reported in a consistent format that clearly communicates them to subsequent readers.

This practice does not define whether or to what extent any person other than the user may use or rely upon a Phase II ESA prepared for the user. The appropriateness of third party use or reliance is a contractual matter that should be addressed between user and Phase II Assessor, see Appendix X2, section X2.4.

PrinciplesThe following principles are an integral part of this practice and are intended to be referred to in resolving any ambiguity or exercising such discretion as is accorded the user or Phase II Assessor.

Elimination of UncertaintyNo Phase II ESA can eliminate all uncertainty. Furthermore, any sample, either surface or subsurface, taken for chemical testing may or may not be representative of a larger population. Professional judgment and interpretation are inherent in the process, and even when exercised in accordance with objective scientific principles, uncertainty is inevitable. Additional assessment beyond that which was reasonably undertaken may reduce the uncertainty.

Failure to DetectEven when Phase II ESA work is executed competently and in accordance with this practice, it must be recognized that certain conditions present especially difficult target analyte detection problems. Such conditions may include, but are not limited to, complex geological settings, unusual or generally poorly understood behavior and fate characteristics of certain substances, complex, discontinuous, random, or spotty distributions of existing target analytes, physical impediments to investigation imposed by the location of utilities and other man-made objects, and the inherent limitations of assessment technologies.

Limitations of InformationThe effectiveness of a Phase II ESA may be compromised by limitations or defects in the information used to define the objectives and scope of the investigation, including inability to obtain information concerning historic site uses or prior site assessment activities despite the efforts of the user and Phase II Assessor to obtain such information in accordance with 5.1.3.

Chemical Analysis ErrorChemical testing methods have inherent uncertainties and limitations. The Phase II Assessor shall build quality control and quality assurance measures into the assessment, as outlined in Section 7. The Phase II Assessor should require the laboratory to report any potential or actual problems experienced, or nonroutine events which may have occurred during the testing, so that such problems can be considered in evaluating the data. The Phase II Assessor should subsequently identify such problems in any reports or documentation provided to the user. Any laboratory utilized for chemical testing shall be accredited in accordance with applicable state requirements.

Level of AssessmentPhase II ESAs do not generally require an exhaustive assessment of environmental conditions on a property. There is a point at which the cost of information obtained and the time required to obtain it outweigh the benefit of the information and, in the context of private transactions and contractual responsibilities, may become a material detriment to the orderly conduct of business. If the presence of target analytes is confirmed on a property, the extent of further assessment is a function of the degree of confidence required and the degree of uncertainty acceptable in relation to the objectives of the assessment.

Comparison With Subsequent InquiryThe justification and adequacy of the findings of a Phase II ESA in light of the findings of a subsequent inquiry should be evaluated based on the reasonableness of judgments made at the time and under the circumstances in which they were made.

Data UsabilityInvestigation data generally only represent the site conditions at the time the data were generated. Therefore, the usability of data collected as part of a Phase II ESA may have a finite lifetime depending on the application and use being made of the data. To the extent that investigation data would fall within the scope of data used in a Phase I ESA conducted pursuant to Practice E1527 or Practice E2247, the lifetime limits defined by those standards apply. In all other respects, a Phase II Assessor should evaluate whether previously generated data are appropriate for any subsequent use beyond the original purpose for which they were collected, or are otherwise subject to lifetime limits imposed by other laws, regulations or regulatory policies.

Phase II Assessor Does Not Provide Legal or Business AdviceThe Phase II ESA is intended to develop and present sound, scientifically valid data concerning actual site conditions. It shall not be the role of the Phase II Assessor to provide legal or business advice.


1.1 This practice covers a process for conducting a Phase II environmental site assessment (ESA) of a parcel of property with respect to the presence or the likely presence of substances including but not limited to those within the scope of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) (e.g., hazardous substances), pollutants, contaminants, petroleum and petroleum products, and controlled substances and constituents thereof. It specifies procedures based on the scientific method to characterize property conditions in an objective, representative, reproducible, and defensible manner. To promote clarity in defining Phase II ESA objectives and transparency in communicating and interpreting Phase II ESA results, this practice specifies adherence to requirements for documenting the scope of assessment and constraints on the conduct of the assessment process.

1.1.1 A user's interest in the presence or likely presence of substances in environmental media at a property may arise in a wide variety of legal, regulatory, and commercial contexts, and may involve diverse objectives including those listed in 1.2. This practice contemplates that the user and the Phase II Assessor will consult to define the scope and objectives of investigation in light of relevant factors, including without limitation the substances released or possibly released at the property, the nature of the concerns presented by their presence or likely presence, the portion of the property to be investigated, the information already available, the degree of confidence needed or desired in the results, the degree of investigatory sampling and chemical testing needed to achieve such confidence, and any applicable time and resource constraints. This practice requires that Phase II activities be conducted so that the resulting scope of work is performed, and the stated objectives are achieved, in a scientifically sound manner.

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Book of Standards Volume: 11.05
Developed by Subcommittee: E50.02
Pages: 21
DOI: 10.1520/E1903-11
ICS Code: 13.020.30