A Phase I Environmental Site Assessment, or Phase I ESA, is a non-invasive environmental due diligence evaluation commonly performed during commercial real estate transactions, refinancing, redevelopment, and infrastructure development. DEA’s Phase I ESAs are performed to meet and exceed the requirements of ASTM E1527-21, as applicable to the assignment.

A typical Phase I ESA includes historical review of the property and surrounding area; review of aerial photographs, fire insurance maps, city directories, and other available historical sources; a physical site reconnaissance; regulatory database review; and interviews with owners, operators, occupants, or other knowledgeable parties when appropriate.

The assessment evaluates whether Recognized Environmental Conditions, or RECs, are present. Findings are documented in a clear report that explains the basis for DEA’s conclusions and identifies whether additional investigation, such as a Phase II ESA, may be warranted.

When a Phase I ESA is useful: before acquiring commercial or industrial property; when required by a lender or investor; before redevelopment or major reconstruction; during refinancing; or when a property is transitioning to a more sensitive use. The purpose is objective environmental due diligence, giving the client a clearer understanding of the property’s environmental history and current conditions before a major decision is finalized.