Health Risk Assessments for California Sites
Encon Environmental prepares health risk assessments and screening-level evaluations to help owners, operators, and agencies understand potential risk from soil, soil vapor, groundwater, and indoor air at sites across California.
Our work focuses on practical, decision-ready assessments that support cleanup, redevelopment, and continued operations while aligning with current California regulatory expectations.
- Risk screening and project-level health risk evaluations.
- Support for cleanup goals, mitigation measures, and land-use decisions.
- Clear communication of technical results to regulators and stakeholders.
What Is a Health Risk Assessment in the Context of California Projects?
A health risk assessment (HRA) evaluates how chemicals in soil, soil vapor, groundwater, or air may affect people who live, work, or visit a site—now or in the future.
For contaminated or potentially impacted properties, HRAs help answer a core question: Do measured concentrations represent an acceptable level of risk for the proposed land use, or is additional cleanup or mitigation warranted?
Encon uses California-relevant exposure assumptions and toxicity values, combined with site-specific data, to quantify potential risk and compare it against regulatory benchmarks. Our work products are designed to dovetail with agency expectations and provide a clear basis for decisions about remediation, mitigation, or land-use controls.
- Evaluate cleanup levels for soil and groundwater at impacted sites.
- Assess vapor intrusion potential to indoor air at existing and new buildings.
- Support decisions about future land use (industrial, commercial, residential, schools).
- Communicate risk to property owners, tenants, and local agencies.
- Document risk reduction achieved by remediation or mitigation measures.
Integrating Health Risk with Investigation and Cleanup
Health risk assessments are most effective when they are integrated with site assessment and remediation planning—not treated as a separate exercise. Encon develops HRAs using data from Phase II investigations, soil and groundwater testing, and building-related surveys to ensure that risk conclusions are grounded in the best available information.
We evaluate exposure pathways that are relevant to your site and land use, such as direct contact with soil, inhalation of vapors that may migrate into indoor air, or potential ingestion of groundwater where applicable. For each scenario, we quantify risk and compare it to acceptable levels for the appropriate receptor (residents, workers, construction workers, or sensitive populations).
- Soil, soil vapor, groundwater, and indoor air data from investigations.
- Conceptual site model describing sources, pathways, and receptors.
- Current and proposed land use (industrial, commercial, residential, schools).
- Existing or planned mitigation (caps, paving, sub-slab systems, ventilation).
- Applicable California guidance and screening values for key contaminants.
Evaluating Pathways, Contaminants, and Exposure Scenarios
Encon tailors each health risk assessment to the specific combination of contaminants and exposure pathways at your site. For some locations, the primary concern may be petroleum hydrocarbons in soil; for others, chlorinated solvents in soil vapor or metals in shallow soil may drive risk.
We structure our analysis so that regulators and stakeholders can clearly see which chemicals, pathways, and exposure scenarios are driving risk—and which are not. This often helps focus subsequent remediation and monitoring on the areas that matter most.
- Direct contact and incidental ingestion of contaminated soil.
- Inhalation of outdoor air and indoor air impacted by soil vapor intrusion.
- Contact with groundwater in excavations or utility trenches, where relevant.
- Petroleum hydrocarbons, VOCs (including chlorinated solvents), SVOCs, PAHs, and metals.
- Site-specific exposure scenarios for workers, residents, and sensitive uses.
Using Health Risk Assessments to Support Cleanup and Land-Use Decisions
The value of a health risk assessment is in how it informs next steps. Encon uses HRA results to help clients and agencies set cleanup goals, prioritize remedial measures, and evaluate whether risk-based closure or long-term management is appropriate for a site.
Depending on the outcome, follow-up actions may include focused remedial excavation, soil or groundwater treatment, installation of vapor mitigation systems, engineering controls, or implementation of land-use or deed restrictions. Our goal is to help you reach a defensible risk position that supports your project schedule and long-term plans for the property.
- Demonstrate that existing risk is acceptable for a given land use.
- Define site-specific cleanup or mitigation targets.
- Support risk-based closure requests and negotiated endpoints.
- Guide design of vapor mitigation and engineering controls.
- Communicate residual risk to owners, tenants, and regulators.
Need a Health Risk Assessment for a California Property or Project?
Whether you are responding to a regulatory request, planning redevelopment, or evaluating residual risk after cleanup, Encon Environmental can prepare a health risk assessment that aligns with California expectations and supports your project goals.
