...

Methodologies

Methodologies Used by RoseyFields Experts

Science-Based Methodologies Evaluated Under Daubert and Analogous Standards

At RoseyFields, our opinions are based on accepted scientific methodologies that have been applied in litigation, regulatory investigations, environmental assessments, and peer-reviewed research. Our work relies on methodologies developed by the U.S. EPA, ATSDR, OSHA, NIOSH, CalEPA, and the broader scientific literature. These methodologies have been repeatedly subjected to judicial scrutiny and are designed to satisfy the reliability requirements of Federal Rule of Evidence 702 and the Daubert standard and its state-law analogues.

 

Air Dispersion Modeling Methodologies

EPA-Approved and Peer-Reviewed Air Modeling

  • AERMOD
  • AERSCREEN
  • CALPUFF (long-range and complex-terrain transport, non-steady-state and multi-day episodes)
  • CALMET (meteorological pre-processor supporting CALPUFF)
  • ALOHA
  • ISCST3
  • SCREEN3
  • AERMET
  • AERMAP
  • BPIP-PRIME (building downwash)
  • AIHA box models
  • Gaussian plume and puff modeling, generally
  • Calibration and back-trajectory reconciliation against ambient monitoring data, deposition data, and soil/dust sampling results

Applications Include

  • PFAS emissions
  • Ethylene oxide
  • Refinery releases
  • Chemical plant emissions
  • Rail yard diesel exhaust
  • Wildfire smoke
  • Chemical fires and explosions
  • Asbestos releases
  • Silica dust
  • Benzene
  • Vinyl chloride
  • Odor and nuisance dispersion
  • Long-range and regional transport where terrain, chemical transformation, or multi-day transport make steady-state models inappropriate

 

Exposure Assessment Methodologies

Human Exposure Reconstruction

RoseyFields evaluates historical and current exposures using accepted exposure science methods.

Exposure Pathways Include

  • Inhalation
  • Soil ingestion
  • Dust ingestion
  • Dermal contact
  • Drinking water ingestion
  • Food chain exposure
  • Vapor intrusion

Methods Include

  • Average Daily Dose (ADD)
  • Lifetime Average Daily Dose (LADD)
  • Chronic Daily Intake (CDI)
  • Time-weighted exposure calculations
  • Occupational exposure reconstruction
  • Residential exposure reconstruction
  • Biomonitoring and biomarker interpretation (e.g., blood/urine metabolite data) where available
  • Job-exposure matrices for occupational cohorts

 

Human Health Risk Assessment

EPA Risk Assessment Guidance

RoseyFields performs:

  • Cancer risk assessments
  • Hazard quotient analyses
  • Hazard index analyses
  • Cumulative and aggregate risk assessments
  • PFAS risk assessments
  • Ethylene oxide risk assessments
  • Diesel exhaust risk assessments
  • Vapor intrusion risk evaluations

Guidance Includes

  • EPA RAGS (Risk Assessment Guidance for Superfund)
  • EPA IRIS
  • ATSDR Toxicological Profiles and Minimal Risk Levels
  • CalEPA OEHHA
  • EPA Regional Screening Levels and Regional Removal Management Levels
  • EPA Provisional Peer-Reviewed Toxicity Values (PPRTVs)

 

Environmental Forensics and Source Attribution

Identifying Responsible Sources

Methodologies include:

  • Historical operations review (permits, production records, Sanborn maps)
  • Historical aerial photograph interpretation (chronological review of aerial imagery to identify operational footprints, disposal areas, spill events, and changes in site conditions over time)
  • Review and reconstruction of emissions reporting (Toxic Release Inventory (TRI) filings, Title V and other air permit emissions reports, National Emissions Inventory (NEI) data, stack testing records, and self-reported regulatory submissions)
  • Chemical fingerprinting (diagnostic ratio analysis, congener/isomer profiling, compound-specific isotope analysis, PAH and PCB Aroclor pattern matching, age-dating of releases)
  • Fate and transport analysis
  • GIS and spatial mapping analysis (layering historical imagery, sampling locations, modeled concentration contours, land use, hydrology, and site operational data into integrated maps)
  • Air pathway reconstruction
  • Water pathway reconstruction
  • Emission inventory reconstruction
  • Historical production and process analysis
  • Multiple-lines-of-evidence source apportionment

Frequently Used In

  • PFAS litigation
  • Refinery litigation
  • Railroad litigation
  • Asbestos litigation
  • Industrial contamination cases
  • Multi-party allocation disputes

 

Statistical and Data Analysis

Quantitative Evaluation of Environmental and Exposure Data

  • ProUCL
  • 95% UCL calculations
  • Geostatistical analysis (kriging, spatial interpolation)
  • Trend analysis (Mann-Kendall and related nonparametric tests)
  • Regression analysis (linear, logistic, dose-response)
  • Meta-analytic and pooled-data statistics
  • Sensitivity analysis
  • Uncertainty analysis
  • Monte Carlo simulation (when appropriate)
  • Confidence interval and hypothesis testing frameworks applied to environmental and occupational datasets
  • Data quality evaluation (outlier screening, non-detect handling, censored-data statistics)

 

Epidemiology and Toxicology

Evaluation of Scientific Literature

RoseyFields reviews:

  • Cohort studies
  • Case-control studies
  • Cross-sectional studies
  • Meta-analyses
  • Systematic reviews
  • Toxicology studies (in vitro, in vivo, mechanistic)
  • Occupational health studies
  • Weight-of-evidence and Bradford Hill causal framework analysis
  • Dose-response evaluation and derivation of points of departure

Chemicals Frequently Evaluated Include

  • PFAS
  • Ethylene oxide
  • Benzene
  • Asbestos
  • Silica
  • Diesel exhaust
  • PCBs
  • Dioxins
  • PAHs
  • Heavy metals
  • Solvents (e.g., TCE, PCE)

 

Water Modeling and Chemical Fate & Transport

Environmental Transport Analysis

  • Groundwater transport modeling
  • Surface water modeling
  • Drinking water distribution system modeling
  • River and stream transport modeling
  • Air-to-soil deposition modeling
  • Air-to-water deposition modeling
  • PFAS transport evaluation
  • Contaminant migration and plume delineation assessment
  • Vadose zone and partitioning analysis
  • BIOSCREEN (natural attenuation modeling for dissolved hydrocarbon plumes)
  • BIOCHLOR (natural attenuation modeling for chlorinated solvent plumes)

 

Industrial Hygiene and Occupational Exposure Evaluation

  • Application of the Hierarchy of Controls (the “IH Pyramid”), evaluating exposure controls in order of reliability: elimination, substitution, engineering controls, administrative controls, and personal protective equipment
  • OSHA Permissible Exposure Limit (PEL) and ACGIH Threshold Limit Value (TLV) comparison and interpretation
  • NIOSH sampling and analytical method review
  • Historical industrial hygiene monitoring data reconstruction
  • Personal protective equipment (PPE) adequacy evaluation
  • Job task analysis and exposure profiling

 

Standard of Care and Hazard Communication Evaluation

  • Evaluation against contemporaneous industry standards and guidance documents
  • Historical review of available pollution control technologies and evaluation of when such controls became feasible, standard, or required for the relevant time period (e.g., baghouses, scrubbers, electrostatic precipitators, vapor recovery systems, and process modifications), assessed against the state of the industry and regulatory landscape at the time
  • Warnings and labeling adequacy assessment (SDS/MSDS review, label history)
  • Regulatory compliance history review

 

RoseyFields’ work product and expert disclosures are prepared with the applicable procedural and evidentiary framework in mind.

Federal Rule of Civil Procedure 26 Disclosure Requirements

  • Timely written expert reports containing all opinions, the basis and reasons for them, and the facts or data considered
  • Full disclosure of qualifications, publications, prior testimony history (typically the preceding four years), and compensation
  • Identification of all materials, data, and literature relied upon

Federal Rule of Evidence 702 and Daubert Framework

  • Evaluation of whether the expert’s scientific, technical, or specialized knowledge will assist the trier of fact
  • Application of methodologies that are testable, subject to peer review and publication, have a known or potential error rate, and are generally accepted within the relevant scientific community
  • Reliable application of the chosen methodology to the specific facts of the case, rather than conclusion-driven reasoning
  • Awareness of relevant state-law analogues to Daubert (e.g., Frye-based and hybrid standards) where applicable

Admissibility Considerations

  • Documentation designed to withstand Daubert/Rule 702 challenges, motions in limine, and cross-examination
  • Clear separation between generally accepted scientific methodology and case-specific application of that methodology
  • Transparent identification of assumptions, limitations, and alternative explanations considered

 

Quality Control and Quality Assurance

  • Independent internal review of calculations, model inputs/outputs, and data transcription
  • Verification of source data against original laboratory reports, regulatory databases, and historical records
  • Documented chain of custody for data and modeling files
  • Version-controlled modeling and calculation workbooks
  • Peer review of draft reports prior to finalization
  • Reproducibility checks — an independent reviewer can rerun the analysis and obtain consistent results

 

Trial Graphics and Demonstrative Exhibits

  • Development of demonstrative exhibits and trial graphics that accurately depict underlying data, modeling results, and exposure timelines without overstatement
  • Concentration contour maps, exposure timelines, and dose-response graphics prepared for use in reports, depositions, and trial
  • Animations and time-lapse renderings of aerial photography, plume dispersion, or site changes over time, where supported by the underlying data
  • Graphics designed to be defensible on cross-examination — every figure traceable back to underlying data and methodology

 

Why These Methodologies Matter

The methodologies used by RoseyFields experts are transparent, reproducible, subject to peer review, and grounded in accepted scientific principles. Every analysis is documented, quality controlled, and designed to withstand scrutiny by regulatory agencies, opposing experts, and courts.