Jill E Ryer-Powder

Human Health Environmental Toxicologist

Specialties & Experience of this Expert Witness

Additional Information

Dr. Ryer-Powder is the Principal Health Scientist at Environmental Health Decisions. She brings more than 30 years of experience in human health risk assessment, litigation support, and occupational toxicology to human health hazard and evaluation projects. Dr. Ryer-Powder is responsible for strategic preparation, project management, and evaluation of chemical toxicity for risk assessment and product hazard evaluation projects. She is called upon to investigate and analyze legal and regulatory issues and controversial claims regarding chemical causation of diseases in humans. Her solid technical background, coupled with her frequent involvement in risk and hazard evaluation projects, gives her a broad perspective on the technical, economic and regulatory considerations for human health hazard evaluation work. Dr. Ryer-Powder has done extensive work in the development of exposure levels for lead, petroleum fuels, and ammonia. She has comprehensively researched the toxicological issues surrounding human exposures to chlorinated and petroleum hydrocarbons, solvents, heavy metals including lead, arsenic, and hexavalent chromium, fertilizers, and insecticides. She has researched the basis for regulatory standards and levels including Maximum Contaminant Levels, Public Health Goals, National Ambient Air Quality Standards, Proposition 65 NSRLs and MADLs, tolerable intake values, cancer slope factors, and reference doses. In her experience in evaluating potential hazards from chemicals, she has worked with the Office of Environmental Health Hazard Assessment, US FDA, USEPA, Cal/EPA Department of Toxic Substances Control, California Regional Water Quality Control Boards, Rhode Island Department of Environmental Health, County of Santa Barbara, Orange County Health Care Agency, Nevada DEP, and Arizona DEQ. Negotiations have involved presentation and approval of health risk assessments, health-based cleanup levels, and the setting of safe levels of exposure in the occupational and public arena. Dr. Ryer-Powder served on the Board of Directors of the American Board of Toxicology and the Board of Trustees for the Toxicology Education Foundation She was a member of the Lead Exposure and Advisory Committee and was chairperson of the Blood Lead Reference Value workgroup. Dr. Ryer-Powder served as a member of the American Conference of Governmental Industrial Hygienists Threshold Limit Value workgroup helping to set occupational exposure limits. She was appointed to USEPA’s Science Advisory Board (SAB). She conducts reviews of scientific manuscripts for scientific journals. Dr. Ryer-Powder has managed and performed hundreds of health risk assessments for local and national clients. Her experience includes Preliminary Endangerment Assessment risk assessments, Proposition 65 evaluations, Vapor Intrusion evaluations, federal and state Superfund sites, Manufactured Gas Plant sites, RCRA sites, and Brownfields sites. She has prepared and reviewed hundreds of Safety Data Sheets (SDSs) and product labels for consumer and industrial products, including petroleum fuels, solvents, metals, fertilizers, pesticides, adhesives, and fabric protectors. She has worked with trade associations, private industry, and regulatory agencies to develop safe exposure levels to petroleum products and ammonia. She has also provided expert testimony in cases involving exposure to chlorinated hydrocarbons, petroleum hydrocarbons, polycyclic aromatic hydrocarbons, PFAS, dioxins, and metals. Dr. Ryer-Powder has lectured on the subject of risk assessment to students in the University of California system.