5 Common Phase I ESA Mistakes (And How to Avoid Them)
Phase I Environmental Site Assessments are the most common environmental due diligence tool in commercial real estate transactions. They're also one of the most frequently done poorly. Here are the five mistakes we see most often and how to avoid them.
Mistake 1: Incomplete Historical Records Review
The historical records review is the backbone of a Phase I ESA. Skipping aerial photograph analysis, ignoring fire insurance maps, or failing to check city directories can miss critical evidence of past uses that created contamination.
**How to avoid it:** Create a systematic records review checklist that covers all required data sources per ASTM E1527-21. Use digital tools that can organize and cross-reference historical records efficiently.
Mistake 2: Inadequate Site Reconnaissance
Walking the property is not optional. Many assessors rush through site reconnaissance, missing visible evidence like stained soil, distressed vegetation, chemical storage areas, or underground storage tank fills.
**How to avoid it:** Develop standardized reconnaissance checklists for different property types. Document everything with geotagged photos, even if it doesn't seem significant at the time. What looks minor during the visit may become important during report writing.
Mistake 3: Ignoring Adjacent Properties
A Phase I ESA must evaluate neighboring properties for potential contamination sources. Dry cleaners, gas stations, industrial facilities, and agricultural operations can impact your subject property through groundwater migration or other pathways.
**How to avoid it:** Expand your records review to include all properties within the ASTM-specified distance. Document adjacent land uses during site reconnaissance and evaluate potential migration pathways.
Mistake 4: Poor Interview Documentation
Interviews with current and past owners, operators, and local officials often reveal critical information about contamination history. But many assessors conduct informal conversations without proper documentation.
**How to avoid it:** Use structured interview questionnaires that cover all required topics. Document interviews with written summaries signed by the interviewee when possible. Record the date, participants, and key information obtained.
Mistake 5: Weak Report Writing
Even a thorough investigation can be undermined by a poorly written report. Reports that don't clearly present findings, fail to properly cite data sources, or don't meet ASTM formatting requirements create regulatory and liability risks.
**How to avoid it:** Use report templates that follow ASTM E1527-21 structure requirements. Implement peer review before report delivery. Maintain consistent formatting and citation standards across all reports.
The Cost of Getting It Wrong
A poorly executed Phase I ESA can result in:
- Loss of the innocent landowner defense under CERCLA
- Delayed transactions due to regulatory pushback
- Unexpected contamination liabilities discovered after closing
- Need to redo the assessment, doubling costs
Investing in quality Phase I ESA execution protects your clients, your reputation, and your bottom line.