Conducting Subsurface Environmental Investigations in Urban Watersheds - Urban Watersheds: Geology, Contamination, and Sustainable Development - page 120

4.2.1 Phase I Environmental Site Assessment
The Phase I ESA is typically the first environmental investigation conducted at a specific
property. The Phase I ESA is conducted with the objective of qualitatively evaluating the
environmental condition and potential environmental risk of a property or site. A prop-
erty is defined here as a parcel of land with a specific and unique legal description. A site
is defined here as a parcel of land including more than one property or easement and
refers to an area of contamination potentially affecting more than one property.
As the first environmental investigation, the Phase I ESA is often regarded as the most
important activity because all subsequent decisions concerning the property are, in part,
based on the results of the Phase I ESA (Rogers 1992). Therefore, great care, scrutiny, scien-
tific inquiry, and objectivity should be exercised while conducting the Phase I ESA.
Standards for conducting Phase I ESAs were published by the American Society for
Testing Materials (ASTM) in 1993 and were revised in 1997, 2000, and 2005 (ASTM 2005a). On
November 1, 2006, the United States Environmental Protection Agency (USEPA) established
federal standards for conducting Phase I ESAs termed “Standards and Practices for All
Appropriate Inquiries” under the Comprehensive Environmental Response Compensation
and Liability Act (CERCLA) of 1980, commonly known as Superfund (USEPA 2005).
Under CERCLA, United States courts have ruled that a buyer, lessor, or lender may be
held responsible for remediation of hazardous substance residues, even if a prior owner
caused the contamination. However, the performance of a Phase I ESA may create a safe
harbor or protection from liability, known as the “Innocent Landowner Defense” for new
purchasers or lenders. Therefore, Phase I ESAs have become the standard type of environ-
mental investigation employed when initially investigating a property.
According to USEPA (2005) requirements, an environmental professional, such as a geol-
ogist, or environmental scientist must conduct the Phase I ESA. General requirements for
conducting a Phase I ESA include
• Extensive review of current and historical written records, operations, and reports
• Extensive site inspection
• Interviews with knowledgeable and key on-site personnel
• Assessment of potential environmental risks from off-site properties
• Data gap or data failure analysis
A Phase I ESA is typically a noninvasive assessment, performed without sampling or
analysis. In some instances, limited sampling may be conducted on a case-by-case basis,
if in the professional judgment of the person conducting the assessment—or due to other
requests or mitigating factors—sampling is justified. In most cases, collecting and analyz-
ing samples is usually deferred to the Phase II investigation, but if it does occur, the sam-
pling conducted during a Phase I ESA may include the following:
• Sediment
• Drinking water
• Surface water
• Groundwater
• Waste material
• Soil