For any industrial or commercial real estate acquisition, a Phase I Environmental Site Assessment (ESA) is an essential tool in the due diligence process and may provide added protection under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Innocent Landowner Defense by identifying responsible parties. The purpose of a Phase I ESA is to identify potential and recognized environmental conditions that may exist or have historically existed at the site before an asset is acquired.

What Is a Phase I ESA?

A Phase I ESA researches the current and previous uses of a property and the potential for impact from adjoining and nearby properties. The investigation does not typically include sampling and analysis but instead combs through existing Federal, State, local and numerous other databases in an effort to identify past uses and/or activities that could have potentially contributed to environmental impairment. A site walk-through is also performed as well as interviews with current and/or past occupants. At the completion of the assessment, the investigator will generate an ASTM E1527-13 compliant report identifying Historical, Potential and/or Recognized Environmental Conditions.

It should be noted that the need for a Phase I ESA is not limited to commercial and industrial property acquisitions but are also conducted for multi-family residential, agricultural, vacant land and even refinancing of properties already owned by the party conducting the Phase I.

Parts of the Phase I ESA

There are typically four parts to a standard Phase I ESA.

Site Visit

A trained inspector will conduct a site walk-through to record and photo-document current site use and conditions. Observations are made regarding various potential issues including the existence of storage tank related fixtures, floor drains, septic systems, distressed vegetation, storage of chemicals etc. Nearby and adjoining properties will also be observed for potential uses that could result in potential impairment of the subject property.

Historical Research and Review of Existing Records

The inspector will review past uses of the property in Federal, State, local and tribal databases to identify current and past uses of hazardous materials in addition to a review of existing files at the applicable State environmental agency for documented environmental incidents. Other information reviewed includes:

  • Aerial photographs
  • Sanborn fire insurance maps
  • Title information
  • City directories
  • Reverse street directories
  • Topographical maps
  • Building permits
  • Planning records
  • Tax Maps records
  • Vapor Screen



The inspector will interview the designated site representative and/or past property owners, operators and occupants familiar with the property.

Report of Findings

Based on the findings of the investigation, the investigator will compile an ASTM E1527-13 compliant report identifying Historical, Potential and/or Recognized Environmental Conditions (RECs). The identified RECs are summarized along with recommendations for addressing these concerns. In the event that identified RECs justify further investigation, a Phase II may be implemented for the collection of physical samples for the delineation of the extent of impact to soil or groundwater.  While a GSI Phase I ESA meets industry standards, it is important to note that other organizations, like Freddie Mac, may have different (or additional) requirements for their ESA reports which should be identified by your lender if applicable.

Get a GSI Phase I Quote Today

GSI has over 30 years of experience in the environmental industry and has been conducting Phase I ESAs since 1999. If you are in need of a cost effective and accurate Phase I ESA as part of your due diligence, call us at 717.691.9799 or contact us online today.