Phase II Environmental Site Assessments in California
Encon Environmental designs and performs Phase II Environmental Site Assessments (subsurface investigations) to confirm the presence or absence of contamination in soil and groundwater at commercial and industrial properties across California.
Building on the findings of a Phase I ESA, our geologists and engineers define a sampling plan that characterizes the nature and extent of impacts and helps you understand regulatory liability, cleanup needs, and implications for site development or closure.
- Targeted subsurface investigations driven by Phase I findings.
- Soil, soil vapor, and groundwater sampling using direct-push and drilling methods.
- Support for UST cleanup fund projects and site closures in the greater Los Angeles area and statewide.
What Is a Phase II Subsurface Investigation?
A Phase II ESA is a field-based investigation designed to confirm whether contaminants are present in soil, soil vapor, or groundwater and to begin defining the extent of those impacts.
Using the Phase I ESA as a roadmap, Encon’s Project Geologists and Environmental Engineers prepare a site-specific sampling plan. The plan focuses on areas where past operations, storage, or spills may have affected subsurface conditions, such as former UST systems, chemical storage, loading areas, drainage pathways, and outfalls.
Results from a Phase II investigation provide the technical basis for evaluating environmental liability, planning remediation, and supporting regulatory and transactional decisions.
- Development of a Phase II ESA sampling plan by a geologist or environmental engineer.
- Targeted sampling locations based on Phase I RECs and site history.
- Safety and utility clearance planning for field activities.
- Field oversight by experienced environmental staff.
- Preparation of a Phase II ESA Investigation Report summarizing findings.
Field Methods, Sampling, and Analysis
Encon performs a range of subsurface investigation methods to evaluate potential releases from past site use. Our crews rely on direct-push Geoprobe rigs and other drilling methods to advance borings, collect samples at multiple depths, and evaluate migration pathways.
Samples are submitted to certified laboratories for analysis of site-relevant contaminants of concern (COCs), such as petroleum hydrocarbons, volatile organic compounds (VOCs), semi-volatile organic compounds (SVOCs), PCBs, PAHs, and metals. Results are interpreted by licensed professionals who are familiar with California regulatory programs and screening levels.
- Geophysical surveys to evaluate for abandoned USTs or underground structures.
- Direct-push (Geoprobe) drilling and soil borings.
- Soil and soil vapor sampling at multiple depths.
- Hydropunch and groundwater sampling.
- Monitoring well installation and development, where warranted.
Reporting, Liability Evaluation, and Cleanup Fund Site Closures
Following field work and laboratory analysis, Encon prepares a Phase II ESA Investigation Report that documents methods, summarizes data, and provides conclusions on the presence or absence of hazardous substances at the site. Where impacts are identified, we describe their nature and apparent extent and discuss implications for regulatory compliance and site development.
For sites with underground storage tank (UST) releases and similar issues, Phase II results often serve as the technical foundation for cleanup strategies and, where applicable, UST cleanup fund claims or low-risk closure requests. Encon has extensive experience supporting these programs in the greater Los Angeles area and throughout California.
- Interpretation of soil, soil vapor, and groundwater data by licensed professionals.
- Comparison to applicable screening levels and regulatory criteria.
- Conceptual site models that describe likely sources and migration pathways.
- Recommendations for remedial alternatives and cost ranges.
- Technical support for UST cleanup fund sites and closure strategies.
Need a Phase II ESA or Subsurface Investigation in California?
Whether your Phase I ESA has identified RECs or a regulator has requested additional assessment, Encon Environmental can design and implement a targeted Phase II investigation that supports both regulatory compliance and your project goals.
