ASTM

ASTM E1527-21 Explained: The U.S. Phase 1 ESA Standard

ASTM E1527-21 is the prevailing standard for Phase I Environmental Site Assessments in U.S. commercial real estate. It defines required records review, site reconnaissance, interviews, and how environmental professionals classify Recognized Environmental Conditions (RECs).

Core Components of ASTM E1527-21

  • Records review (historical sources, regulatory databases, aerial photographs)
  • Site reconnaissance (visual inspection of property and adjoining areas)
  • Interviews with owners, occupants, and local stakeholders
  • Environmental professional evaluation and REC conclusions
  • Report deliverable with findings and recommendations

User Responsibilities

The standard assigns “User” responsibilities—often the buyer or lender—to disclose known environmental liens, specialized knowledge, and common-environment issues. Missing User inputs can create data gaps.

FAQ

What is ASTM E1527-21?

It is the ASTM standard practice for Phase I Environmental Site Assessments, updated from the 2013 edition with clarified definitions and emerging contaminant considerations.

Do all Phase 1 ESAs follow ASTM E1527?

Lender-grade Phase 1 ESAs in the U.S. typically do. Always confirm the proposal cites the current ASTM edition your lender expects.

What is a REC under ASTM E1527?

A Recognized Environmental Condition indicates the presence or likely presence of hazardous substances or petroleum products due to release—see our REC vs HREC vs CREC guide for subclasses.

Related guides

Phase 1 ESA cost guide · Cost calculator · All guides