Phase I and II Environmental Site Assessments (ESA) Requirements

Phase I ESA


The purpose of a Phase I ESA is to identify recognized environmental conditions (RECs) generally defined as the presence or likely presence of any hazardous substance or petroleum product on the subject property under conditions that indicate an existing release, a past release, or a material threat of a release into structures, or into the ground, groundwater, or surface water of the subject property or contiguous and surrounding properties.


Phase I ESAs performed in accordance with the American Society for Testing and Materials (ASTM) Standard Practice E 1525-13 will satisfy the all appropriate inquiry (AAI) rule under the Federal Superfund Law or Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). While CERCLA has provided statutory defenses for innocent landowners, prospective purchasers, and contiguous property owners, those defenses are available only if there was “all appropriate inquiry” into the environmental condition of the property.

Scope of Work

Historical Review

  • County Appraisal and Deed Records
  • City Permit and Fire Marshal Records
  • Aerial Photographs
  • Sanborn Fire Insurance Maps
  • City Directories

Federal and State Agency File Review

US Environmental Protection Agency (EPA)
  • National Priority List (NPL) and Superfund Sites
  • Registered Hazardous Waste Generators
Oregon Department of Environmental Quality (DEQ)
  • Confirmed Release List (CRL)
  • Environmental Cleanup Site Information (ECSI) Database
  • Underground Storage Tank (UST) Facilities and Cleanup Sites


  • Owners and others knowledgeable of the current and historical use of the subject property

Site Reconnaissance Survey

  • Subject property inspected for the presence of “recognized environmental conditions”

Preparation of Final Report

  • Documentation of all findings
  • Present conclusions and, as appropriate, recommendations for further assessment (i.e., Phase II ESA)

Phase II ESA


Based upon the findings of the Phase I ESA, a Phase II ESA may be recommended. The purpose of the Phase II ESA is to further assess identified “recognized environmental conditions.”

Scope of Work

The Phase II scope of work typically includes the following:

  • Determination of the presence of contamination through sampling and laboratory analysis
  • Comparison of analytical results with applicable regulatory cleanup standards
  • Preparation of final report presenting findings and, if necessary, recommendations for further assessment (e.g., delineation of vertical and lateral extent of confirmed contamination)

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