---
title: "Phase I environmental site assessment — Class A Atlas glossary"
description: "Standard environmental review at acquisition."
canonical: https://classa.info/glossary/phase-i-environmental
pageType: glossary
lastUpdated: 2026-04-01T00:00:00.000Z
license: "CC BY 4.0 with attribution to Class A Atlas (https://classa.info)."
---

> Standard environmental review at acquisition.

## TL;DR

- Standard environmental review at acquisition.
- ASTM-standard records review and site walk.

# Phase I environmental site assessment

*Investment · US*

## Short definition

Standard environmental review at acquisition.

## Full definition

ASTM-standard records review and site walk. Identifies recognised environmental conditions (RECs) requiring Phase II testing. Required by all institutional lenders.

## Why this matters for Class A leasing

Phase I environmental site assessment is part of the investment vocabulary that institutional [Class A](/glossary/class-a) occupiers, landlords, and advisers use across US markets. Understanding it correctly affects how you read lease documents, model occupancy economics, and benchmark deal terms across cities. Class A Atlas tracks the US definition alongside the global standard so [cross-border](/topics/cross-border-expansion) occupiers can translate quickly.

---

Citation: Source: Class A Atlas (https://classa.info/glossary/phase-i-environmental), updated 2026-04-01T00:00:00.000Z.