Risk Assessment

Risk assessment is a systematic approach to assessing the potential health risks associated with exposure to known or potentially toxic agents. The elements of a risk assessment include data evaluation, exposure assessment , dose-response evaluations (toxicology ), and risk characterization. Risk assessments can be used in a variety of contexts, including evaluating exposure to chemicals in environmental and occupational settings, or assessing exposure to chemicals in foods, consumer products, or medical devices.

The results of an environmental risk assessment can help determine the need for and nature of remedial actions at hazardous waste sites, support the derivation of cleanup levels, and assist in permitting new facilities and developing closure plans for facilities that are going out of service. At Exponent, our scientists and engineers conduct and critique site-specific risk assessments and derive risk-based remediation goals for hazardous waste sites and facilities under a variety of federal and state regulatory frameworks. Our risk assessors have applied their expertise to perform site-specific analyses and assist our clients in developing effective strategies for managing hundreds of sites.

Our scientists also apply their risk assessment expertise to safety evaluations for medical devices and combination products. Such assessments have been applied during the development process to ensure the products meet safety standards under use conditions, as well as after the products have been in use to assess the likelihood of a relationship between the device and potential health issues.

Our services encompass all components of human health risk assessment projects including;


  • Data evaluation 
  • Development of conceptual site models and site-specific exposure 
  • Screening-level and advanced level exposure calculations
  • Derivation of risk-based cleanup levels 
  • Bioavailability studies 
  • Fish consumption surveys and studies 
  • Toxicity (dose response modeling) assessments 
  • Chemical Fate and Transport modeling 
  • Vapor intrusion assessments 
  • Emissions characterization and air dispersion modeling 
  • Monte Carlo approaches and quantitative uncertainty analysis 
  • Research and development to address sources of uncertainty 
  • Risk communication in public forums, seminars, and presentations

We can perform exposure assessments involving any contaminant and all media to which an individual can be exposed, including soil, indoor dust, drinking water, surface water, outdoor and indoor air, contact with residues on surfaces, through breast milk, and consumption of locally-grown or harvested fruits, vegetables, meat, dairy or egg products, and fish. We are involved in the leading exposure assessment scientific societies and have made numerous contributions to the scientific literature in the field of exposure assessment, including for potentially sensitive groups, such as children or highly exposed subsistence populations. 

We effectively communicate our approaches and results to industry, regulatory personnel, and the public. Our presentations at national and international meetings, and our published research papers and articles in the peer-reviewed literature, cover many of these issues. These efforts have earned us a well-established scientific reputation and lend greater credibility to our assessments. 

Publications and Presentations 

Garry MR. Dietary survey study design considerations for fish consumption studies used in regulatory decision making. Oral presentation at Society of Environmental Toxicology and Chemistry North America 35th Annual Meeting, Vancouver, BC, Canada, 2014.

Garry MR. Communicating science to the public. Oral presentation at Society of Toxicology’s 51st Annual Meeting, San Francisco, CA, 2012.

Garry MR, Saba T, Mohsen F, Hilbert B. Health assessment of methanol used in hydraulic fracturing fluids. Poster presented at Society of Toxicology’s 51st Annual Meeting, San Francisco, CA, 2012.

Kalmes R. Understanding the USEPA-type risk-based evaluation of environmental data. Presented at California Industrial Hygiene Council, San Diego, CA, December 5, 2012. 

Kalmes R, Brorby B, Lowney Y. Dioxin/furan site-specific bioaccessibility for application at Industrial Site. Battelle 8th International Conference, Remediation of chlorinated and Recalcitrant Compounds, Monterey, CA, May 24, 2012. 

Tsuji JS, Garry MR, Perez V, Chang ET. Low-level arsenic exposure and developmental neurotoxicity in children: A systematic review and risk assessment. Toxicology 2015; 337:91–107.

Tsuji JS, Perez V, Garry MR, Alexander, DD. Association of low-level arsenic exposure in drinking water with cardiovascular disease: A systematic review and risk assessment. Toxicology 2014; 323:78–94.

Yost LJ, Shock SS, Holm SE, Lowney YW, Noggle JJ. Lack of complete exposure pathways for metals in natural and FGD gypsum. Human and Ecological Risk Assessment: An International Journal 2010; 16(2): 317–339. 

Kalmes R. Hicks J. A method to evaluate lead surface dust concentrations in non-residential settings. Presented at American Industrial Hygiene Conference and Exposition, PDC 138, June 2009. 

Menzie CA, Ziccardi LM, Lowney YW, Fairbrother A, Shock SS, Tsuji JS, Hamai D, Proctor D, Henry E, Su SH, Kierski MW, McArdle ME, Yost LJ. Importance of considering the framework principles in risk assessment for metals. Environ Sci Technol 2009; 43(22):8478–8482.

Barraj LM, Tsuji JS, Scrafford CG. The SHEDS-Wood Model: Incorporation of observational data to estimate exposure to arsenic for children playing on CCA-treated wood structures. Environ Health Perspect 2007; 115(5):781–786.

Professionals