Paul Turnham

Paul Turnham, P.E.

Senior Managing Scientist
Health Sciences

Mr. Turnham trained as a civil and environmental engineer and is licensed as a professional engineer. He has more than 20 years of experience working in the fields of quantitative human health risk assessment, exposure assessment, dose reconstruction, site characterization and environmental fate and transport.

Mr. Turnham’s expertise is in the development and application of site-specific approaches to risk and exposure assessment for regulatory and in support of litigation. He specializes in the distillation of large data sets, providing succinct quantitative and graphical summaries of exposure and risk. He has applied this expertise cases involving claims of personal injury arising from exposure to chemicals and other substances (both site and product related). His experience has involved a number of agents of concern including chlorinated solvents, petroleum compounds, heavy metals, polycyclic aromatic hydrocarbons, polychlorinated biphenyls, dioxins, and chrysotile and amphibole forms of asbestos. He has performed individual-specific dose reconstructions and risk estimation associated with human exposures to environmental media, ambient and indoor air, indoor dust, and consumer products. He has designed and implemented chamber and field activity-based simulations for data collection to support these efforts. He has provided risk and exposure assessments for industrial and residential sites including Superfund, RCRA, and state oversight cleanup sites and for air emissions sources such as hazardous waste-burning cement kilns, coal-fired power plants and coke oven batteries. He has evaluated exposure and risks from vapor intrusion at residential, commercial, and industrial properties. He also has designed and implemented site investigations and remedial actions at sites subject to state regulations, RCRA, and voluntary clean-up programs.

Mr. Turnham is experienced in supporting due diligence activities for property transfers. His work in this arena includes assessment of physical and operational aspects of manufacturing sites across various industrial sectors and states. He has conducted facility level audits for compliance with federal and state environmental and health and safety regulations.


  • M.S., Civil Engineering (Environmental Option), Virginia Polytechnic Institute and State University, 1994
  • B.Eng., Civil Engineering, University of Bristol, UK, 1988


Professional Engineer, Virginia, #0402-029004


Anderson EL, Turnham P, Griffin JR, Clarke CC. Consideration of the Aerosol Transmission of COVID-19 and Public Health. Risk Analysis 2020; 40(5): 902-907.

Moolgavkar SH, Anderson EL, Chang ET, Lau EC, Turnham P, Hoel DG. A review and critique of U.S. EPA’s risk assessments for asbestos. Critical Reviews in Toxicology 2014; Early Online: 1–24. DOI: 10.3109/10408444.2014.902423.

Anderson E, Griffin J, Turnham P. Lessons learned from catastrophic releases to the environment: Catastrophic releases that impact human health can be chronic or acute. Poster presented at Reckoning with the Risk of Catastrophe - Deutsche Forschungsgemeinschaft (DFG) and the U.S. National Science Foundation (NSF) Research Conference, Washington, DC, October 2012.

Turnham P, Richter R, Griffin J. Estimating indoor air exposure concentrations of biodegradable VOCs using API’s BioVapor Spreadsheet Model. Poster presented at Society for Risk Analysis Annual Meeting 2012, San Francisco, CA, December 2012.

Barabas N, Turnham P, Helfand J, Griffin J, Dunkin J. A tiered approach to fingerprinting dioxins—Distinguishing between an HCP manufacturing source and a barrel reconditioning facility. Presented at the 31st Annual Meeting in North America of the Society of Environmental Toxicology and Chemistry, Portland, OR, November 2010.

Turnham P. Field investigation and risk assessment for the vapor intrusion pathway. Presented at the Arizona Department of Environmental Quality and U.S. Environmental Protection Agency meeting of the Motorola 52nd Street Superfund Site Community Advisory Group, Phoenix, AZ, 2005.

Richter RO, Griffin JR, Turnham P, Lau E. Release of naturally occurring arsenic via reductive dissolution at petroleum contaminated sites. AEHS Conference, San Diego, CA, March 2017.

Turnham P, Anderson EL, Turim J. Dermal absorption of PCBs in non-aqueous carriers. Presented at the Society of Risk Analysis 23rd Annual Meeting, Baltimore, MD, 2003.

Turim J, Turnham P, Griffin J. Computing asbestos risk using life tables. Presented at the Society of Risk Analysis 23rd Annual Meeting, Baltimore, MD, 2003.

Patrick DR, Turnham P. Multipathway risk assessment of a cement kiln combusting hazardous waste. Presented at the 94th Annual Conference and Exhibition, Air & Waste Management Association, Orlando, FL, June 2001.

Moore MA, Hanna LM, Grumm DM, Turnham P, Yu CP, Jubb GA. Biopersistence of insulation glass fibres. Annals of Occupational Hygiene1997; 41(inhaled particles VIII):312–319. doi:10.1093/annhyg/41.inhaled_particles_VIII.312

Book Chapter

Anderson EL, Lowe K, Turnham P. Chapter 1. In: Cancer Risk Assessment: Chemical Carcinogenesis, Hazard Evaluation, and Risk Quantification. John Wiley & Sons, Inc., 2010.

Prior Experience

Project Director, Sciences International, Inc., 2003–2006

Project Manager, Sciences International, Inc., 1999–2003

Senior Associate, Sciences International, Inc., 1997–1999

Associate, Sciences International, Inc., 1995–1997

Analyst, Sciences International, Inc., 1994–1995

Engineer III, EG&G Washington Analytical Services Center, 1992–1994

Civil Engineer, J.E.M. Van Der Beek Associates (UK), 1988–1990 

Professional Affiliations

Society for Risk Analysis, 2003–present

American Society of Civil Engineers

Project Experience

Supported litigation testimony involving releases of PCBs to rivers in WI and MI from paper recycling mills. Managed team review of historical toxicity testing and knowledge of potential for environmental and health impacts from PCBs prior to the early 1970s.

Provided risk assessment related support to a PRP group at a Superfund site in New England where dioxin and PCB-contaminated sediment and associated fish ingestion risks are the primary risk drivers. Provided comments on USEPA's draft baseline risk assessment that resulted revisions to the final risk assessment. Reviewed historical site data including synthesis of recollections of prior site employees, chemical manufacturing information, and other data sources. Display of site data in intuitive graphical approaches that were presented to US EPA Region 3 and have been subsequently relied upon by others. Developed a novel method to allocate source-specific contributions using site data, baseline risk assessment, site-specific remedial goals and environmental forensics.

Evaluated bio-degradation of petroleum hydrocarbons in soil gas for a residential site in California. Provided expertise in backwards forecasting of historical soil vapor levels and past risk.

Provided technical support for litigation projects involving consumer exposure to talcum powder products alleged to contain amphibole asbestos. Provided technical expertise for inhalation exposure assessment in the design and implementation of a chamber simulation to replicate alleged usage and in a study comparing glove box and room chamber environments. Has deep knowledge of USEPA risk models for asbestos (1986, 2008), sampling techniques, analytical methods (NIOSH 7400, 7402, IOS 10312), and data requirements.

Managed a project involving potential exposures to residual chrysotile asbestos-containing pipe wrap in Colorado and Nebraska. The project included design and oversight of activity-based sampling to quantify asbestos releases during actual agricultural and simulated residential activities in soils at multiple locations over a large land area. Technical risk-assessment based support was provided for data quality objectives. Oversaw and directed the team responsible for design of field activity based sampling program.

Provided risk and exposure assessments for air emissions of hexane from a proposed soybean oil processing facility in PA.

Directed and managed data analysis for land impacts for a large oil spill. This involved assembling all publically available data for the gulf coast including worker industrial hygiene and shoreline and inland air monitoring data.

Managed analysis of data from buildings and ambient air in the vicinity of the World Trade Center, post 9/11. This involved assembling, combining data sets from a variety of sources and understanding exposure patterns for building clean-up workers.

Evaluated vapor intrusion risks and hazards for a large fuel storage terminal site in California. The assessment evaluated both indoor and outdoor air concentrations. Groundwater and soil gas data were used to provide screening level risk estimates for offsite residents and workers.

Evaluated indoor air risk for a commercial site in Arizona. The work, performed for the Arizona DEQ, involved integration of indoor air data, modeled indoor air concentrations from vapor intrusion and ambient outdoor air data.

Provided litigation support in cases involving exposure to arsenic in indoor dust alleged to be associated with agricultural soil amendment with chicken litter. Evaluated and critiqued indoor dust-to-air models and risk calculations presented by opposing experts.

Conducted risk analysis for a matter involving human exposure to DDT and associated compounds in indoor dust. Gave advice on the appropriate indoor dust sampling protocols for use in exposure assessment and identified the areas within a home that should be sampled for indoor dust health assessment. Provided interpretation of indoor dust sampling data using an exposure and risk model developed by EPA for the World Trade Center. Evaluated risk to adults and children.

Developed a risk assessment work plan for assessment of vapor intrusion into residences at Superfund site in Arizona. The plan included design of vapor intrusion sampling and analysis. The plan was reviewed and approved by the Arizona DEQ and EPA Region 9. Presented at a public hearing.

Managed a project involving understanding of the potential for off-site impacts from a proposed demolition of a residential area in Chicago. Contaminants of concern included, lead, organics and other building material related substances.

Evaluation of interstate impacts of power plant emissions. This involved analysis and graphical presentation of large data sets generated by modelling (CAMx, CMAQ). These covered large portions of the eastern US.

Performed a review of baseline human health risks for litigation for a Superfund site in Pennsylvania where PCBs were the main contaminants of concern. Notable was the re-assessment of dermal exposure to PCBs in oil, which was disseminated at the 2003 annual meeting of the Society for Risk Analysis.

Provided risk assessment support for a site in New Jersey underlain by chromium ore processing waste residues. The work included, on and offsite air dispersion modelling, ecological considerations and direct exposure via ingestion and contact with solids and groundwater (cancer/non-cancer risk, dermatitis).

Directed a human health risk assessment to support a voluntary cleanup action at an aircraft-manufacturing site in Maryland. The assessments, performed by tax parcel, evaluated risks to current and hypothetical future residents, recreational users, workers and site visitors arising from potential exposures to substances in soil, groundwater, surface water, sediments and indoor air. Managed all aspects of the project including data analysis, development of spreadsheet algorithms, and creation of innovative techniques to efficiently compute the risks on a point-by-point basis and, using GIS software, to display the results.

Evaluated potential exposures to coke oven emissions and evaluated EPA's assessments of risk associated with emissions from U.S. coke oven batteries. Assisted in the development of a presentation and report on the results of the study to EPA's Office of Air Quality, Planning and Standards (OAQPS). Assisted in the development of a revised methodology for dispersion modeling for coke oven batteries. This involved a novel approach to address buoyant line source plume rise using a combination of EPA’s ISC and BLP dispersion models. Presented this methodology to the OAQPS along with case studies. The agency subsequently adopted the methodology in its risk assessment for rulemaking under the Clean Air Act's residual risk program. Later managed the application of the air dispersion methodology for coke oven batteries sites. Also reviewed the risk assessments performed by OAQPS, which were based on that methodology.

Conducted a multi-pathway/multimedia risk assessment for cement kiln burning hazardous waste in 1997/98. Developed spreadsheet-based algorithms which modeled the fate and transport of over one hundred chemicals including dioxins and mercury emitted from this site into the following direct and indirect exposure pathways: inhalation, ingestion, and dermal absorption of soil and surface water, ingestion of homegrown fruits and vegetables and animal products. The work included selection and application of fate and transport models to estimate chemical runoff into surface water bodies, uptake into fruits and vegetables, and bio-transfer into animal products. Risks were estimated for residents including the mother's milk pathway (for dioxins), subsistence farmers, recreational anglers, hunters, and swimmers. The risk assessment was submitted to USEPA and the state and was subject to public comment. USEPA Region 3 and the state of Pennsylvania subsequently endorsed the risk assessment. Led subsequent work on this project including a quantitative assessment of threshold effect risks for dioxins using the margin of incremental exposure approach and assistance in developing a risk-based protocol by which to measure future compliance.



  • M.S., Civil Engineering (Environmental Option), Virginia Polytechnic Institute and State University, 1994
  • B.Eng., Civil Engineering, University of Bristol, UK, 1988


Professional Engineer, Virginia, #0402-029004