An environmental site assessment (ESA) is a report prepared for a real estate holding that identifies potential or existing environmental contamination liabilities. The analysis, often called an ESA, typically addresses both the underlying land as well as physical improvements to the property.

which identifies potential or existing environmental contamination liabilities.  The analysis addresses both the underlying land as well as physical improvements to the property.  The examination of a site includes the definition of any chemical residues within the structures such as the possibility of asbestos containing materials, inventory of hazardous substances stored or used on-site, assessment of mold or mildew, lead-based paint, and a competent historical background on the subject properties and their surroundings.  The Phase I ESA is generally considered the first step in the process of due diligence.  If a site is considered contaminated, a Phase II Environmental Site Assessment may be required.

Phase II Environmental Site Assessments, also known as a Subsurface Investigation, is an intrusive investigation which collects original samples of soil, groundwater or building materials to analyze for quantitative values of various contaminants.  This investigation is normally undertaken when a Phase I ESA determines the likelihood of site contamination.  The most frequent substances tested are petroleum hydrocarbons, heavy metals, pesticides, solvents, asbestos, lead and mold.

Phase III Environmental Site Assessments, also known as a Remedial Design and Application, is an investigation involving the remediation of a site.  The purpose of the Phase III is to delineate the physical extent of contamination based on recommendations made in the Phase II report.  The Phase III is a remedial design using the most recent studies and modeling programs detailing alternative cleanup methods while taking into consideration the costs and logistics for the most effective restoration systems available today for the clean up of impacted soil and ground water.