Phase I and Phase II Environmental Site Assessments serve different purposes.
A Phase I ESA is primarily an environmental due diligence assessment designed to identify recognized environmental conditions based on historical research, regulatory information, site reconnaissance, interviews, and other reasonably ascertainable information.
A Phase II ESA generally involves physical investigation and sampling to evaluate whether suspected contamination is actually present.
Phase I ESA
A Phase I ESA typically includes:
The Phase I ESA generally does not involve laboratory sampling.
Its purpose is to identify environmental conditions that may warrant further evaluation.
- Historical research
- Regulatory database review
- Regulatory file review
- Site reconnaissance
- Interviews
- Review of previous environmental reports
- Evaluation of surrounding properties
- REC/CREC/HREC evaluation
When Is a Phase II ESA Considered?
A Phase II ESA may be appropriate when the Phase I ESA identifies a condition that cannot be adequately evaluated through available records and visual observations.
Potential triggers may include:
- Evidence of a petroleum release
- Historical UST release
- Chlorinated solvent contamination
- Dry-cleaning operations with potential releases
- Industrial operations with potential chemical releases
- Documented soil contamination
- Groundwater contamination
- Historical spills
- Unresolved regulatory cases
- Suspected vapor intrusion conditions
What Does a Phase II ESA Involve?
Depending upon site conditions and the suspected contaminant source, a Phase II investigation may include:
The scope should be developed based on the specific environmental concern identified during the Phase I ESA.
- Soil borings
- Soil sampling
- Groundwater monitoring wells
- Groundwater sampling
- Soil vapor sampling
- Indoor air evaluation
- Laboratory analysis
- Geophysical investigation
- Other subsurface investigation techniques
A Phase II Is Not Automatically Required for Every REC
The identification of a REC does not mean that a Phase II ESA must automatically be performed.
The environmental professional should consider the nature of the condition and available information.
For example, a documented release may already have been investigated and remediated, with sufficient regulatory documentation available to understand the condition.
Conversely, a historical release with limited documentation and potential migration toward the subject property may warrant additional investigation.
The Role of Professional Judgment
The decision to recommend additional investigation should consider:
The objective is to determine whether additional investigation is necessary to reduce uncertainty associated with the identified environmental condition.
A Phase I ESA identifies potential environmental risk. A Phase II ESA can provide physical evidence to further evaluate that risk.
At Greenearth, we support environmental professionals with Phase I research, regulatory review, historical analysis, and environmental risk evaluation that can assist in determining whether additional investigation may be appropriate.
- Nature of the suspected release
- Location of the source
- Potential contaminants
- Regulatory status
- Historical operations
- Available sampling data
- Soil conditions
- Groundwater conditions
- Potential contaminant migration
- Current and proposed property use