Phase I ESA

A Phase I Environmental Site Assessment is the transaction convention for environmental diligence: a records review, site reconnaissance, and history reconstruction — conducted to a recognized standard — identifying conditions that suggest contamination. It samples nothing; its output is recognized environmental conditions, the findings that either clear the deal's conscience or send it to Phase II, where soil and groundwater actually get tested.

The instrument matters legally as well as practically: a conforming Phase I is part of establishing certain defenses to federal cleanup liability for innocent purchasers. Its records-based nature is also its limit — it can only find what history recorded, which is why tank registries, spill files, and old use records carry the weight they do.