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Patrick J. Sheehan, Ph.D.

Principal Scientist

Exposure Assessment & Dose Reconstruction

Professional Profile


Dr. Sheehan is a toxicologist, ecologist, and risk assessor with more than 30 years experience conducting human health and ecological risk assessments. Dr. Sheehan has been recognized as an expert in exposure and risk assessment. He has managed and conducted human health and ecological risk assessments at contaminated sites, industrial and commercial facilities and for consumer products, evaluating chemicals released to air, surface water, groundwater, soils, hands and food items. He specialized in assessing and quantifying potential historical, current or future exposures to chemicals in the environment, workplace and home, and associated health risks. He has designed and directed studies to simulate and reconstruct historical exposures in occupational and residential settings to benzene and other volatile chemicals in solvents, asbestos in adhesives and roofing products and lead in various consumer products. He has also evaluated potential future chemical exposures associated with new facilities or combustion sources and new products. Dr. Sheehan has also designed and directed wildlife population assessments, aquatic toxicity tests, toxicity identification evaluations, risk allocation evaluations, human and probabilistic uncertainty analyses. Dr. Sheehan frequently interacts with local, state, and federal regulatory agencies and has testified as an expert before government panels and in legal proceedings on toxicology, exposure and human health and wildlife risks.

  • Ph.D., Toxicology/Ecology, University of California, Davis, 1980
  • M.S., Ecology, University of California, Davis, 1975
  • B.S., Mechanical Engineering, Santa Clara University, 1968