When a site is suspected of environmental contamination—whether due to past industrial use, accidental spills, or redevelopment of brownfields—the first step toward cleanup is a comprehensive remediation site assessment. This process provides the critical data needed to evaluate risk, determine the extent of contamination, and create a safe, compliant plan for remediation.
At O6 Environmental, we treat the site assessment as a foundational step—one that sets the tone for the success of the entire project. Here’s what property owners, facility managers, and developers can expect from this phase, and how we ensure it’s done right.
What Is a Site Assessment?
A remediation site assessment is a formal investigation of a property’s environmental condition. It’s designed to answer key questions such as:
- Is contamination present?
- What types of contaminants exist?
- How far have they migrated?
- What cleanup methods are appropriate?
- What are the associated risks and liabilities?
Site assessments are often required during property transactions, permitting processes, regulatory investigations, or before redevelopment projects.
Two Common Phases of Assessment
Environmental site assessments typically unfold in two major phases:
Phase I ESA (Environmental Site Assessment)
A non-intrusive review that includes:
- Historical land use and records research
- Site walk-through and visual inspections
- Interviews with owners, tenants, and local officials
- Review of regulatory databases and past incidents
The goal is to identify Recognized Environmental Conditions (RECs)—potential indicators of contamination that warrant further investigation.
Phase II ESA
If RECs are found, a Phase II assessment involves:
- Collection of soil, groundwater, surface water, or building material samples
- Laboratory testing for pollutants (e.g., hydrocarbons, metals, PCBs, VOCs)
- Subsurface evaluations (e.g., drilling, test pits, geophysical surveys)
- Development of contaminant maps and exposure pathway models
This phase quantifies the extent and type of contamination and is the gateway to remediation planning.
Key Steps in a Remediation Site Assessment
1. Pre-Assessment Planning
O6 Environmental collaborates with stakeholders to define objectives, regulatory requirements, site history, and sampling strategies. This ensures the assessment is cost-effective and aligned with compliance needs.
2. Field Investigation
Our field crews mobilize with all necessary PPE, sampling equipment, and decontamination protocols. Common field activities include:
- Soil boring and sampling
- Groundwater monitoring well installation
- Air quality sampling (especially in buildings)
- Direct-push technology for rapid site screening
All fieldwork is conducted under a site-specific Health and Safety Plan (HASP).
3. Laboratory Analysis
Collected samples are submitted to certified laboratories for EPA-approved analysis. Turnaround times typically range from 5–10 business days, depending on the analytes.
4. Data Interpretation and Risk Evaluation
We use the results to assess:
- Contaminant concentration levels
- Migration pathways (e.g., groundwater, vapor intrusion)
- Exposure risks to humans or ecosystems
- Applicable cleanup standards based on site use (residential vs. industrial)
This step determines whether remediation is required—and to what extent.
5. Reporting and Recommendations
We prepare a detailed report including:
- Maps and cross-sections of contaminant plumes
- Analytical data tables and lab certifications
- Risk characterization and regulatory comparison
- Recommendations for remediation methods and next steps
Why Site Assessments Are Critical
A properly executed assessment:
- Reduces uncertainty before project investments
- Prevents costly surprises during development
- Supports regulatory compliance and liability protection
- Forms the basis of an effective remediation plan
- Provides leverage in real estate negotiations or insurance claims
In short, it turns speculation into actionable data.
Common Contaminants We Encounter
Our site assessments frequently identify:
- Petroleum hydrocarbons from leaking tanks
- Heavy metals in fill soils or from industrial operations
- PCBs in old building materials and transformers
- Asbestos-containing materials
- Solvents, degreasers, and VOCs in former manufacturing spaces
Partnering with O6 Environmental
With decades of experience in industrial, commercial, and government projects, O6 Environmental brings:
- Licensed environmental professionals (LEPs and CHMMs)
- Full in-house field crews and equipment
- Deep regulatory knowledge across EPA regions
- Clear communication and defensible reporting
From assessment to full cleanup, we serve as your partner in environmental responsibility.
Conclusion: It All Starts with the Right Data
No remediation project can move forward without an accurate understanding of site conditions. A site assessment is not just a box to check—it’s the foundation of safe, effective environmental cleanup.
When you partner with O6 Environmental, you gain access to seasoned professionals who know how to deliver assessments that stand up to regulators, lenders, and redevelopment partners alike.


