Phase I Environmental Site Assessment
A Phase I ESA brings historical research, agency records, interviews, and a site reconnaissance together to evaluate recognized environmental conditions in connection with a property. It gives buyers, lenders, and owners a documented basis for their next decision.
What is a Phase I ESA?
A Phase I Environmental Site Assessment evaluates evidence of releases or likely releases of hazardous substances or petroleum products associated with a property. It considers current conditions and earlier uses. The conclusion reflects the information reasonably available and the professional judgment applied; it is not a certification that a property is free of contamination.
ASTM E1527-21 and All Appropriate Inquiries
EPA recognizes ASTM E1527-21 as consistent with its All Appropriate Inquiries (AAI) rule. AAI is a pre-acquisition inquiry relevant to certain CERCLA landowner liability protections. The report scope, intended user, property boundaries, and component dates matter. A completed report alone does not establish or preserve every requirement for a liability protection.
What is included in the assessment?
The scope combines a site reconnaissance, historical-use research, government-record review, interviews, and an environmental professional’s evaluation. Available prior reports and the user’s information help shape that work. The report explains findings, conclusions, limitations, and significant data gaps. Agree on lender requirements and any additional services when the proposal is prepared.
What happens during the site visit?
The reconnaissance documents reasonably observable conditions, such as chemical storage, tanks, staining, drains, waste handling, and indications of former operations. Access to buildings, tenant spaces, yards, and relevant equipment improves the assessment. Locked rooms, stored materials, snow, or unsafe areas can limit observations and should be documented.
Does Phase I include soil or groundwater testing?
Ordinarily, no. A Phase I ESA evaluates existing information and observable conditions; intrusive sampling is a separately scoped investigation. If the assessment identifies an unresolved concern, targeted soil, groundwater, or soil-vapor sampling may help answer it. Testing should address a defined question rather than simply collecting samples across a property.
What needs a separate scope?
Asbestos, lead-based paint, radon, mold, wetlands, geotechnical conditions, and a property condition assessment are generally outside the standard Phase I ESA scope. They may still matter to a transaction or redevelopment. Identify these needs early so the appropriate specialists and deliverables can be included without treating the Phase I as an all-purpose building inspection.
Related guidance
Browse the Phase I ESA information hub
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Primary references
General guidance does not replace a property-specific assessment. The applicable standard, regulations, scope, and available evidence govern the evaluation.