

- Ph.D., Environmental Health Sciences, University of Michigan, Ann Arbor, 2015
- M.S., Environmental Health, Harvard University, 2006
- B.S., Anthropology, University of Michigan, Ann Arbor, 2003
- Certified Industrial Hygienist (CIH)
- Sponsored Affiliate in the Occupational & Environmental Epidemiology Program, University of Michigan School of Public Health, 2015-2017
- Exponent HERO Award for Best Technical Achievement in a Project, 2021
- Exponent HERO Award for Best Colleague Development, 2020
- NIEHS Intramural Paper of the Month (Muñoz et al. 2018), November 2018
- AIHA Conference Scholarship, 2015
- AIHA John A. Leonowich Award (for educational excellence in non-ionizing radiation), 2015
- University of Michigan Rackham Predoctoral Fellow, 2014-2015
- University of Michigan Rackham International Travel Grant, 2013
- National Institute for Occupational Safety and Health Graduate Fellowship, 2005-2006, 2011-2012
- University of Michigan James B. Angell Scholar, 2004
- University of Michigan University Honors, 2001-2003
- American Industrial Hygiene Association (AIHA), 2004-present
- International Society of Exposure Science (ISES), 2013-present
- International Society for Environmental Epidemiology (ISEE), 2023-present
Dr. Ryan Lewis is a Principal Scientist in Exponent's Health Sciences practice. He has more than 15 years of scientific consulting and research experience in the areas of exposure science, industrial hygiene, and environmental epidemiology. He was educated at the University of Michigan (B.S. and Ph.D.) and Harvard University (M.S.). His work involves the evaluation of exposures and health effects at the individual and population levels, in occupational and non-occupational settings, and from consumer and industrial product use scenarios. He is experienced with a wide range of agents such as asbestos, bisphenol A, ethanol, ethylene oxide, glass fibers, heavy metals, non-asbestiform minerals, pesticides, phthalates, power-frequency magnetic fields, silica, talc, and wood dust.
Dr. Lewis has published 32 peer-reviewed scientific papers, which have been cited more than 1,200 times. His papers address three primary areas: 1) epidemiologic analyses and systematic literature reviews of environmental exposures and health endpoints; 2) evaluation of exposure measurement error, exposure misclassification, and confounding in epidemiology studies; and 3) characterization, predictors, and contextualization of exposures. Dr. Lewis is on the editorial board of Frontiers in Public Health and was formerly on the editorial boards of Journal of Toxicology and Environmental Health and Toxicology and Industrial Health. He has also served as an invited reviewer for more than 20 scientific journals.
Peer-Reviewed Papers
Krevanko, C.F., A.M. Hernandez, A.M Gauthier, M.S. Vahora, R.C. Lewis, J.S. Pierce. 2025. Potential influence of cancer history on mesothelioma incidence: An ecologic analysis in the U.S. population. Journal of Public Health 47(4):e540-e545.
Hernandez, A.M., S.J. Smith, M.S. Vahora, D. Campbell, C.F. Krevanko, R.C. Lewis, and J.S. Pierce. 2025. Systematic review of the epidemiology of hair relaxer use and hormone-sensitive reproductive outcomes among Black adult women in the United States. Journal of Applied Toxicology 45(8):1394-1416.
Roberts, B., R. Lewis, S. Smith, E. Miller, and J. Pierce. 2025. Historical cosmetic talc consumption and incidence of mesothelioma in the United States. International Journal of Environmental Health Research 35(4):972-980.
Miller, E.W., E.M. Beckett, D. Cheatham, C.E. Comerford, R.C. Lewis, C. Krevanko, N. Mandava, and J.S. Pierce. 2024. A review of the mesotheliogenic potency of cleavage fragments found in talc. Toxicology and Industrial Health 40(7):398-424.
Beckett, E.M., A. Abelmann, B. Roberts, R.C. Lewis, D. Cheatham, E.W. Miller, E. Hall, and J.S. Pierce. 2023. An updated evaluation of reported no-observed adverse effect levels for chrysotile, amosite, and crocidolite asbestos for lung cancer and mesothelioma. Critical Reviews in Toxicology 53(10):611-657.
Lewis, R.C., S.J. Smith, C.F. Krevanko, E.D. Hall, E.W. Miller, E.M. Beckett, and J.S. Pierce. 2023. Occupational exposure to cosmetic talc and mesothelioma in barbers, hairdressers, and cosmetologists: a systematic review of the epidemiology. Toxicology and Industrial Health 39(10):564-582.
Lewis, R.C., P.J. Sheehan, C.G. DesAutels, H.N. Watson, and C.R. Kirman. 2022. Monitored and modeled ambient air concentrations of ethylene oxide: Contextualizing health risk for potentially exposed populations in Georgia. International Journal of Environmental Research and Public Health 19(6):3364.
McCoy, M.J., R.C. Lewis, and F.S. Mowat. 2021. Airborne concentrations of chrysotile asbestos during operation of industrial crane controls and maintenance of associated arc chutes. Toxicology and Industrial Health 37(3):124-133.
Sheehan, P.J., R.C. Lewis, C.R. Kirman, H.N. Watson, E.D. Winegar, and J.S. Bus. 2021. Ethylene oxide exposure in U.S. populations residing near sterilization and other industrial facilities: Context based on endogenous and total equivalent concentration exposures. International Journal of Environmental Research and Public Health 18(2):607.
Kirman, C.R., A.A. Li, P.J. Sheehan, J.S. Bus, R.C. Lewis, and S.M. Hayes. 2021. Ethylene oxide review: Characterization of total exposure via endogenous and exogenous pathways and their implications to risk assessment and risk management. Journal of Toxicology and Environmental Health, Part B: Critical Reviews 24(1):1-29.
Lewis, R.C., R. Rauschenberger, and R. Kalmes. 2021. Hand-to-mouth and other hand-to-face touching behavior in a quasi-naturalistic study under controlled conditions. Journal of Toxicology and Environmental Health, Part A: Current Issues 84(2):49-55.
Ingle, M.E., L. Mínguez-Alarcón, R.C. Lewis, P.L. Williams, J.B. Ford, R. Dadd, R. Hauser, J.D. Meeker, and for the EARTH Study Team. 2020. Association of personal exposure to power-frequency magnetic fields with pregnancy outcomes among women seeking fertility treatment in a longitudinal cohort study. Fertility and Sterility 114(5):1058-1066.
Bogen, K.T., R.C. Lewis, A. Singhal, and P.J. Sheehan. 2020. Development of a novel method for estimating dermal contact with hand-applied cleaning solutions. Environmental Monitoring and Assessment 192(3):157.
Muñoz, M.G.I., J.A. Colacino, R.C. Lewis, A.E. Arthur, J.D. Meeker, and K.K. Ferguson. 2018. Associations between school lunch consumption and urinary phthalate metabolite concentrations in US children and adolescents: Results from NHANES 2003-2014. Environment International 121:287-295.
Lewis, R.C., J.D. Meeker, N. Basu, A.M. Gauthier, A. Cantoral, A. Mercado-García, K.E. Peterson, M.M. Téllez- Rojo, and D.J. Watkins. 2018. Urinary metal concentrations among mothers and children in a Mexico City birth cohort study. International Journal of Hygiene and Environmental Health 221(4):609-615.
Lewis, R.C., L. Mínguez-Alarcón, J.D. Meeker, P.L. Williams, G. Mezei G, J.B. Ford, R. Hauser, and the EARTH Study Team. 2017. Self-reported mobile phone use and semen parameters among men from a fertility clinic. Reproductive Toxicology 67:42-47.
Ferguson, K.K., J.A. Colacino, R.C. Lewis, and J.D. Meeker. 2017. Personal care product use among adults in NHANES: Associations between urinary phthalate metabolites and phenols and use of mouthwash and sunscreen. Journal of Exposure Science and Environmental Epidemiology 27(3):326-332.
Lewis, R.C., L.E. Johns, and J.D. Meeker. 2016. Exploratory analysis of the potential relationship between urinary molybdenum and bone mineral density among adult men and women from NHANES 2007-2010. Chemosphere 164:677-682.
Lewis, R.C., R. Hauser, A.D. Maynard, R.L. Neitzel, L. Wang, R. Kavet, and J.D. Meeker. 2016. Exposure to power- frequency magnetic fields and the risk of infertility and adverse pregnancy outcomes: Update on the human evidence and recommendations for future study designs. Journal of Toxicology and Environmental Health, Part B: Critical Reviews 19(1):29-45.
Lewis, R.C., R. Hauser, A.D. Maynard, R.L. Neitzel, L. Wang, R. Kavet, P. Morey, J.B. Ford, J.D. Meeker, and the EARTH Study Team. 2016. Personal measures of power-frequency magnetic field exposure among men from an infertility clinic: Distribution, temporal variability, and correlation with their female partners' exposure. Radiation Protection Dosimetry 172(4):401-408.
Lewis, R.C., R. Hauser, L. Wang, R. Kavet, and J.D. Meeker. 2016. Personal power-frequency magnetic field exposure in women recruited at an infertility clinic: Association with physical activity and temporal variability. Radiation Protection Dosimetry 168(4):478-488.
Lewis, R.C., L.E. Johns, and J.D. Meeker. 2015. Serum biomarkers of exposure to perfluoroalkyl substances in relation to serum testosterone and measures of thyroid function among adults and adolescents from NHANES 2011-2012. International Journal of Environmental Research and Public Health 12:6098-6114.
Omoike, O.E., R.C. Lewis, and J.D. Meeker. 2015. Association between urinary biomarkers of exposure to organophosphate insecticides and serum reproductive hormones in men from NHANES 1999-2002. Reproductive Toxicology 53:99-104.
Lewis, R.C., K.R. Evenson, D.A. Savitz, and J.D. Meeker. 2015. Temporal variability of daily personal magnetic field exposure metrics in pregnant women. Journal of Exposure Science and Environmental Epidemiology 25(1):58-64.
Bowman, D.M., R.C. Lewis, C. Yeo, and M. Lee. 2015. The growing public health challenges of exposure to ultraviolet radiation from use of indoor tanning devices in the United States. New Solutions: A Journal of Environmental and Occupational Health Policy 25(2):164-171.
Lewis, R.C., D.E. Cantonwine, L.V. Anzalota Del Toro, A.M. Calafat, L. Valentin-Blasini, M.D. Davis, M.A. Montesano, A.N. Alshawabkeh, J.F. Cordero, and J.D. Meeker. 2015. Distribution and determinants of urinary biomarkers of exposure to organophosphate insecticides in Puerto Rican pregnant women. Science of the Total Environment 512-513:337-344.
Lewis, R.C., and J.D. Meeker. 2015. Biomarkers of exposure to molybdenum and other metals in relation to testosterone among men from the United States National Health and Nutrition Examination Survey 2011- 2012. Fertility and Sterility 103(1):172-178.
Lewis, R.C., D.E. Cantonwine, L.V. Anzalota Del Toro, A.M. Calafat, L. Valentin-Blasini, M.D. Davis, S.E. Baker, A.N. Alshawabkeh, J.F. Cordero, and J.D. Meeker. 2014. Urinary biomarkers of exposure to insecticides, herbicides, and one insect repellent among pregnant women in Puerto Rico. Environmental Health 13(1):97.
Lewis, R.C., J.D. Meeker, K.E. Peterson, J.M. Lee, A. Cantoral, and M.M. Tellez-Rojo. 2013. Predictors of urinary bisphenol A and phthalate metabolite concentrations in Mexican children. Chemosphere 93(10):2390- 2398.
Lewis, R.C., R.R.M. Gershon, and R.L. Neitzel. 2013. Estimation of permanent noise-induced hearing loss in an urban setting. Environmental Science and Technology 47(12):6393-6399.
Lewis, R.C., S.H. Gaffney, M.H. Le, K.M. Unice, and D.J. Paustenbach. 2012. Airborne concentrations of metals and total dust during solid catalyst loading and unloading operations at a petroleum refinery. International Journal of Hygiene and Environmental Health 215(5):514-521.
Beebe-Dimmer, J.L., L.A. Lange, J.E. Cain, R.C. Lewis, A.M. Ray, A.V. Sarma, E.M. Lange, and K.A. Cooney. 2006. Polymorphisms in the prostate-specific antigen gene promoter do not predict serum prostate-specific antigen levels in African-American men. Prostate Cancer and Prostatic Diseases 9(1):50-55
Book Contributions
Hicks, J., and R. Lewis. 2024. Chapter 12 — Health Risks of Fungi in the Built Environment. In: Human and Ecological Risk Assessment: Theory and Practice, 3rd Edition. D.J. Paustenbach (ed.), Wiley.
Singhal, A., M. Posson, R. Kalmes, A. Gauthier, R. Lewis, J. Schenk, E. Goswami, and P. Sheehan. 2018. Case Studies — Proposition 65 Risk Assessment. In: Professional Practices of Product Stewardship. F.A. Hart (ed.), Product Stewardship Society.
Response to Commentary
Lewis, R.C., L. Mínguez-Alarcón, J.D. Meeker, P.L. Williams, G. Mezei, J.B. Ford, and R. Hauser. 2017. Response to correspondence by Mortazavi et al. re: "Self-reported mobile phone use and semen parameters among men from a fertility clinic". Reproductive Toxicology 71:165.
Presentations
Scientific Conference Abstracts
Smith, S.J., M.S. Vahora, R.C. Lewis, and J.S. Pierce. 2024. A Systematic Review of the Epidemiology of Hair Relaxer Use and Hormone-Sensitive Reproductive Outcomes in Adult Women. Poster presentation at AIHA Connect 2024. May 20-22, 2024, Columbus, OH.
Lewis, R.C., S.J. Smith, C.F. Krevanko, E.D. Hall, E.W. Miller, E.M. Beckett, and J.S. Pierce. 2024. Occupational Exposure to Cosmetic Talc and Mesothelioma in Barbers, Hairdressers, and Cosmetologists: A Systematic Review of the Epidemiology. Poster presentation at AIHA Connect 2024. May 20-22, 2024. Columbus, OH.
Lewis, R.C., K. Krevanko, S.E. Brown, and E.W. Miller. 2023. Revisiting Asbestos Fiber Exposure Science to Inform the Characterization of Inhalation Exposure to Matrix-Bound Particulates During Consumer Product Use Scenarios. Poster presentation at American Industrial Hygiene Conference & Exposition. May 22-24, 2023. Phoenix, AZ.
Sheehan, P., R.C. Lewis, and C. DesAutels. 2022. Ethylene Oxide Monitoring and Modeling Concentrations: Providing Health Risk Context for Potentially Exposed Populations. Podium presentation at Air Quality Measurement Methods and Technology Conference (specialty conference of Air & Waste Management Association). March 8-10, 2022. San Diego, CA.
Lewis, R.C. 2021. Scientific Considerations for Communicating Risks Associated with Talc. Podium Presentation at PSX (Product Stewardship Conference). September 28-30, 2021. Anaheim, CA.
Sheehan, P., J. Bus, R.C. Lewis, E. Winegar, and A. Li. 2020. An Assessment of Historical Occupational and Non-Occupational Ethylene Oxide Exposure Questions the Applicability of EPA's 10-6 Increase in Cancer Risk at an Exposure Level of 0.1 ppt. Poster presentation at Society of Toxicology Meeting. March 15-19, 2020. Anaheim, CA.
Lewis, R.C., K.T. Bogen, A. Singhal, and P.J. Sheehan. 2018. Use of a Novel Method for Estimating Dermal Contact with Hand-Applied Aqueous and Petroleum-Based Cleaning Solutions. Podium presentation at American Industrial Hygiene Conference & Exposition. May 20-23, 2018. Philadelphia, PA.
Sheehan, P., R. Kalmes, M. Posson, A. Singhal, R. Lewis, and A. Gauthier. 2018. Challenges in Assessing Health Risk from Exposure to Bisphenol A (BPA) in Consumer Products. Poster presentation at Society of Toxicology Meeting. March 11-15, 2018. San Antonio, TX.
Gauthier, A.M., and R.C. Lewis. 2017. Challenging Exposure Assessment Assumptions: A Volatile Cleaning Product Case Study. Podium presentation at PSX (Product Stewardship Conference). November 2-4, 2017. Tampa, FL.
Ferguson, K.K., R.C. Lewis, J.D. Meeker, and J.A. Colacino. 2017. Self-Reported Consumption of School Lunches and Urinary Phthalate Metabolite Levels in US Children. Podium presentation at International Society of Exposure Science Annual Conference. October 15-19, 2017. Durham, NC.
Gauthier, A., R. Lewis, K. Bogen, A. Singhal, and P. Sheehan. 2017. Wearable Technology Biocompatibility: A Unique Opportunity in Green Chemistry and Engineering. Poster presentation at the Annual Industrial Roundtable Poster Reception of Annual Green Chemistry and Engineering Conference. June 13-15, 2017. Reston, VA.
Lewis, R.C., E. Winegar, M. Posson, A.M. Gauthier, A. Singhal, and P.J. Sheehan. 2017. Exposure to an Ethanol- Based Cleaning Product. Podium presentation at American Industrial Hygiene Conference & Exposition. June 3-5, 2017. Seattle, WA.
Singhal, A., K.T. Bogen, R.C. Lewis, A. Gauthier, E. Winegar, and P. Sheehan. 2017. A Novel Approach to Estimating Dermal Contact with Hand-Applied Cleaning Solutions: A Simulation Study Involving Denatured Alcohol. Poster presentation at Society of Toxicology Meeting. March 12-16, 2017. Baltimore, MD.
Winegar, E., K. Bogen, R.C. Lewis, A. Singhal, and P. Sheehan. 2017. A Use-Simulation Study of a Denatured Alcohol Cleaning Product to Assess Potential Worker Exposure. Poster presentation at Society of Toxicology Meeting. March 12-16, 2017. Baltimore, MD.
Singhal, A., M. Posson, A. Jones, R.C. Lewis, J. Schenk, R. Kalmes, and P. Sheehan. 2016. Assessing Risk for Consumer Products under California's Proposition 65 Regulations. Poster presentation at Society of Environmental Toxicology and Chemistry Annual Meeting. November 6-10, 2016. Orlando, FL.
Gauthier, A., R. Lewis, and R. Kalmes. 2016. Hand-to-Mouth Contact Frequency Among Adults: Review of the Literature and Recommendations for Future Studies. Poster presentation at Society of Environmental Toxicology and Chemistry Annual Meeting. November 6-10, 2016. Orlando, FL.
Lewis, R.C., A. Singhal, A. Gauthier, R. Kalmes, and P. Sheehan. 2016. Proposed Methods for Characterizing Dermal Exposure to BPA for Purposes of Proposition 65. Poster presentation at Society for Risk Analysis Annual Meeting. December 11-15, 2016. San Diego, CA.
Lewis, R.C., J.D. Meeker, L. Mínguez-Alarcón, G. Mezei, and R. Hauser. 2016. Self-Reported Cell Phone Use Patterns and Semen Quality Parameters Among Men from an Infertility Clinic. Poster presentation at BioEM2016 (Bioelectromagnetics). June 5-10, 2016. Ghent, Belgium.
Lewis, R.C. 2016. Exposure to Power-Frequency Magnetic Fields and Risk of Adverse Reproductive Health Outcomes: The Case for Additional Research. Podium presentation at American Industrial Hygiene Conference & Exposition. May 21-26, 2016. Baltimore, MD.
Lewis, R.C., J.D. Meeker, K.E. Peterson, A. Cantoral, L. Schnaas, and M.M. Tellez-Rojo. 2013. Predictors of Urinary Bisphenol A and Phthalate Metabolite Concentrations in Mexican Children. Poster presentation at International Society of Environmental Epidemiology, International Society of Exposure Science, and International Society of Indoor Air Quality and Climate Joint Annual Conference. August 19-23, 2013. Basel, Switzerland.
Lewis, R.C., S.H. Gaffney, M.H. Le, K.M. Unice, and D.J. Paustenbach. 2011. Airborne Concentrations of Metals and Total Dust During Solid Catalyst Loading and Unloading Operations at a Petroleum Refinery. Poster presentation at International Society of Exposure Science Annual Conference. October 23-27, 2011. Baltimore, MD.
Lewis, R.C., R.F. Herrick, K.T. Tan, and M.R. Yep-Abu. 2006. Dilution Ventilation to Control Welding Fumes in a Crude Oil Tank at a Shipyard in Singapore. Poster presentation at American Industrial Hygiene Conference & Exposition. May 13-18, 2006. Chicago, IL.
Lewis, R.C. 2009. Global Welding Practices: Manganese Exposure Assessment, Control, and Litigation. Roundtable arranger at American Industrial Hygiene Conference & Exposition. May 30-June 4, 2009. Toronto, Canada.
Other Scientific Presentations
Lewis, R.C. 2022. Revisiting the Fundamental Role of Standard "Fiber" Counting Rules in Asbestos Exposure Science and Risk Assessment. Podium presentation at Association of Defense Counsel of Northern California and Nevada Toxic Torts Seminar. June 3, 2022. San Francisco, CA.
Hauser R., and R.C. Lewis. 2014. Magnetic Fields and Pregnancy Loss: Four-Year Study Among Couples from a Fertility Clinic. Joint podium presentation at the Electric Power Research Institute Electric and Magnetic Fields and Radio-Frequency Health Assessment and Safety Scientific Advisory Committee Meeting. September 3, 2014. Palo Alto, CA.
Lewis R.C. 2014. Biological Hazards. Guest lecture in EHS 550: Introduction to Occupational and Environmental Health. University of Michigan School of Public Health, Department of Environmental Health Sciences. November 3, 2014. Ann Arbor, MI.
Hauser R., and R.C. Lewis. 2014. Magnetic Fields and Pregnancy Loss: Four-Year Study Among Couples from a Fertility Clinic. Joint podium presentation at the Electric Power Research Institute Environmental Program Council Advisory Meeting. February 25, 2014. San Francisco, CA.
Lewis R.C. 2013. Biological Hazards. Guest lecture in EHS 550: Introduction to Occupational and Environmental Health. University of Michigan School of Public Health, Department of Environmental Health Sciences. October 28, 2013. Ann Arbor, MI.
Lewis R.C. 2013. Exposure to 60 Hz MFs and Reproductive Health. Guest lecture in EHS 657: Advanced Exposure Assessment. University of Michigan School of Public Health, Department of Environmental Health Sciences. April 9, 2013. Ann Arbor, MI.
Lewis R.C. 2012. Epidemiology: A Brief Overview. Guest instructor in the Comprehensive Industrial Hygiene Review. University of Michigan Center for Occupational Health and Safety Engineering. March 12, 2012. Ann Arbor, MI.
Lewis, R.C. 2006. Dilution Ventilation to Control Welding Fumes in a Crude Oil Tank at a Shipyard in Singapore. Podium presentation at Harvard School of Public Health Seminar Series in Occupational Health. April 25, 2006. Boston, MA.
Research Grants
NIOSH ERC 2017 Pilot Project Research Training Program, Icahn School of Medicine at Mount Sinai
Scientific Journals
American Journal of Preventive Medicine
Annals of Occupational Hygiene
BMC Public Health
BMJ Open
Chemosphere
Ear and Hearing
Ecotoxicology and Environmental Safety
Environment International
Environmental Health Perspectives
Environmental Pollution
Environmental Research
International Archives of Occupational and Environmental Health
International Journal of Hygiene and Environmental Health
International Journal of Environmental Research and Public Health
Journal of Exposure Science and Environmental Epidemiology
Journal of Occupational and Environmental Hygiene
Journal of Toxicology and Environmental Health, Part A: Current Issues
Journal of Toxicology and Environmental Health, Part B: Critical Reviews
Regulatory Toxicology and Pharmacology
Safety Science
Science of the Total Environment
Toxicology and Industrial Health
Frontiers in Public Health (section: Environmental Health and Exposome), 2023-present
Journal of Toxicology and Environmental Health, 2015-2018
Toxicology and Industrial Health, 2015-2016
Principal Health Scientist and Director, Benchmark Risk Group, 2025
Managing Health Scientist and Director, Benchmark Risk Group, 2023-2024
Managing Health Scientist, Benchmark Risk Group, 2022-2023
Managing Scientist, Exponent, Inc., 2015-2022
Graduate Student Research Assistant, University of Michigan School of Public Health, 2011-2015
Associate Health Scientist to Senior Associate Health Scientist, ChemRisk, LLC, 2008-2011
Scientist to Staff Scientist, Golder Associates Inc., 2006-2008
Research Assistant, University of Michigan Cancer Center, 2003-2004