Home • Services • Risk Assessment

RETRA’s scientists specialize in risk assessment, providing expert analysis of chemical, environmental, and product-related exposures to determine potential health risks and support regulatory, legal, and mitigation decisions.

Consulting Expertise

» Dose Estimation

» Exposure Reconstruction

» Environmental Sampling

» Expert Witness & Litigation Support

» Human Health Risk Characterization

» Multi-route Exposure Assessments

» Regulatory Compliance

» Site-Specific Risk Assessments

» Statistical & Epidemiological Analysis

» Water Reuse Evaluations

Selected Project Experience

Industrial Incident Response – Air Emissions: RETRA scientists have supported emergency response and retrospective evaluations for industrial incidents involving airborne chemical releases. Work included real-time and historical air quality data analysis, contaminant dispersion modeling, and assessment of chemical infiltration into homes and communities. Select examples include evaluating exposure pathways and health risks following the Aliso Canyon natural gas blowout, a fire at a metal recycling facility, and a warehouse chemical spill.

PFAS and Biosolids Risk Evaluation: Assessed health risks associated with PFAS and other contaminants in biosolids applied to forage crops at a large agricultural site in California. The evaluation supported legal proceedings, including expert testimony.

Solvent Release and Brownfield Redevelopment Support: Directed site investigations and health risk assessments for properties impacted by chlorinated solvents in soil and groundwater. Services supported both responsible parties and prospective buyers engaged in redevelopment or remediation planning.

Environmental Contamination – Soil and Dust: RETRA scientist have conducted risk assessments involving residual contamination in surface media such as soil and dust. Projects included evaluating health risks from lead-laden fugitive dust emitted by an automotive recycling facility and assessing potential exposure to chemical residues is wildfire smoke and ash. These assessments involved identification of exposure pathways, receptor populations, and application of health-protective screening benchmarks.

Manufactured Gas Plant Site Portfolio Management: Developed a framework for managing risk at former manufactured gas plant (MGP) sites on behalf of utilities and the U.S. Navy. This included comparing post-remediation and background PAH levels, performing risk assessments at over a dozen southern California sites, and negotiating cleanup strategies with state regulators.

Agricultural and Water Reuse Risk Assessment: RETRA scientists have provided technical evaluation for agricultural reuse of treated oilfield-produced water in food crop irrigation. Efforts included reviewing chemical occurrence data, conducting hazard assessments for known and naturally occurring constituents, and analyzing crop sampling results. This work informed policy discussions and risk management decisions by regulatory agencies overseeing water reuse in California’s Central Valley.

Mine Tailings and Residential Exposure Assessments: Completed health risk evaluations for residential communities built on or exposed to arsenic- and lead-containing mine tailings, addressing both chronic exposure and incidental ingestion pathways.

Community Risk from Industrial Air Emissions: Evaluated exposure and health risks for communities adjacent to industrial operations, including a bauxite processing facility and diesel emissions from rail yards and port activities in California.

Critical Evaluation of Regulatory Health Factors: Provided technical review of unit risk factors and concentration-response functions used by regulatory agencies such as California’s OEHHA, particularly in relation to diesel particulate matter.

Oil Refinery and Petroleum Site Risk Characterization: Conducted multipathway risk assessments for petroleum-impacted sites using site-specific exposure pathways and risk-based screening levels to identify contaminants of concern and prioritize management actions.

Children’s Health Risk from Vinyl Chloride: Applied EPA age-sensitive methodologies to evaluate risks associated with vinyl chloride exposure, with a focus on the increased vulnerability of children.

Hazardous Waste Facility Permitting: Completed comprehensive risk assessments in support of environmental permits for hazardous waste treatment, storage, and disposal facilities, addressing inhalation, dermal, and ingestion pathways.

Pesticide Residues in Redevelopment Projects: For over 20 redevelopment projects involving agricultural land, assessed health risks from residual pesticides in surface soils. Collaborated with agency representatives to establish cleanup goals and developed plain-language disclosures for developers and lending institutions.