What is a Phase I environmental site assessment?
A Phase I environmental site assessment is a study of a property's past and present uses, done by an environmental professional, to find likely contamination before a purchase. It looks and asks; it does not sample.
In more detail
Most Phase I reports follow ASTM E1527-21, the standard EPA recognizes as meeting its All Appropriate Inquiries rule. The work has four parts: a records review (government databases and historical sources like aerial photos, fire insurance maps and city directories), a site visit, interviews with owners and occupants, and a written report by the environmental professional.
The output is a list of recognized environmental conditions (RECs) and the professional's opinion on them. A Phase I usually takes a few weeks and costs a few thousand dollars.
For a buyer to rely on it under federal law, parts of the report must be no older than 180 days at purchase, and the report itself no older than a year.
What it means when you buy
A Phase I is what lenders require and what preserves your defenses under federal cleanup law. A pre-screen does not replace it. It helps you decide, before you spend on one, whether a deal is worth pursuing and what to ask the consultant to look at.
How the pre-screen handles it
The pre-screen covers much of the same public record (historical aerials and maps, federal and state databases, flood maps) in a desk review, usually within the hour. It has no site visit, no interviews and no environmental professional's opinion.
Pre-screen a property before you spend on a Phase I
A desk review of one address: past uses from historical photos and maps, federal and state environmental records, and flood risk, ready usually within the hour. $100 for one report, or $100/month for 3.