The ASTM E1527-21 outlines the current process for conducting a Phase I Environmental Site Assessment (ESA). A Phase I ESA is a non-intrusive (no sampling) assessment aimed at providing opinions regarding potential environmental liabilities associated with a property. Its primary objective is to identify and assess whether past or current activities on the subject property, adjoining properties, or nearby properties have, or could likely have, resulted in a Recognized Environmental Condition (REC) in connection with the subject property.

RECs are generally defined as the presence or likely presence of hazardous substances or petroleum products on a property due to a release. The presence or likely presence of such a release may affect property value or usability and indicate potential environmental liabilities.

Additional components in connection with a Phase I ESA in addition to a REC are also determined to include:

  • Controlled Recognized Environmental Condition (CREC), which is a REC where cleanup has occurred, but the use of the subject property has been restricted (usually through the use of engineered barriers or institutional controls associated with a No Further Action (NFA), No Further Remediation (NFR) letter, or Certificate of Completion)
  • Historical Recognized Environmental Condition (HREC) which is used when there was a REC in the past, but it has been cleaned up with no use restrictions.

Applicable Situations

Phase I ESAs are typically conducted in connection with commercial real estate, typically for one of four general reasons:

  • The property is being acquired
  • The property is being sold
  • The property is being re-financed
  • The property is being re-insured

In most cases, a lending institution or government agency requires the performance of a Phase I ESA. Initiating a Phase I ESA early in the process can assist the user of the Phase I ESA become aware of issues that could affect the property's value or development potential. 

Related Standards & Legislation

Phase I ESAs are currently performed in general conformance with one of two ASTM standards, ASTM E1527-21 Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process or ASTM E2247-23 Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process for Forestland or Rural Property.

Phase I ESAs also intersect with the legal requirements of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) for conducting “All Appropriate Inquiry” (AAI) to assist in potentially qualifying for Landowner Liability Protections (LLPs). A Phase I ESA, which is performed under the supervision of an environmental professional (EP) as defined by the AAI regulation, is one of the items needed to qualify for a LLP.

Additional environmental assessment practices include ASTM E1903, for a Phase II Environmental Site Assessment, and ASTM E2600, which covers vapor encroachment conditions (VECs) onto a property.

Key Elements of a Phase I ESA include:

  • Regulatory and Historical Records Review
    A thorough examination of various relevant documents and databases to examine property records, historical uses, and potential environmental liabilities associated with the property and adjoining properties.
  • Site Reconnaissance
    A visual survey of the subject property and surrounding areas to identify signs of RECs, such as hazardous materials, waste storage, storage tanks, any spills or leaks, distressed vegetation, or unusual odors.
  • Interviews
    Engaging with subject property owners and occupants, and local officials to collect relevant information about the property's history and current use and to obtain insights that might not be evident from the site reconnaissance or document reviews.
  • Vapor Encroachment Screen (VES)
    Vapor intrusion can pose significant health risks due to the potential accumulation of hazardous vapors from volatile organic compounds (VOCs), petroleum hydrocarbons, and other hazardous substances. Data obtained during the Phase I ESA is evaluated regarding the potential for vapor to encroach onto the subject property.
  • Report Preparation
    The findings and conclusions, are compiled into a detailed report that documents the assessment, provides opinions regarding the environmental status of the property, and, if recommendations are requested, proposed next steps. Recommendations are not required by the ASTM standards.

There are also additional ASTM Non-Scope considerations, also known as Business Environmental Risks (BERs) that can be addressed during a Phase I ESA. These commonly include:

  • Visual asbestos survey
  • Visual lead-based paint survey
  • Visual fungal (mold) survey
  • Desktop radon records review
  • Desktop lead in drinking water records review
  • Desktop wetlands records review
  • Desktop floodplains records review
  • Desktop historical oil & gas wells records review
  • Desktop seismic zone records review
  • Desktop protected species review
  • Desktop historical places & archeological sites records review

For detailed information on this standard and the applicable regulations, please refer to the official ASTM documentation.