Professional Profile
Dr. William (Bill) Klaren is a board-certified toxicologist in ToxStrategies’ Health Practices Division. With a Ph.D. in Human Toxicology and more than nine years of experience across both academia and industry, he brings broad toxicological, risk assessment, and project management expertise to the consulting environment. During his career, Dr. Klaren has evaluated the toxicological impact of a wide range of chemistries including agrochemical, cosmetic, and consumer good ingredients.
Dr. Klaren has performed numerous risk assessments on consumer products, covering pest control, cosmetics, and air-care products. In that capacity, he has evaluated a wide range of chemistries, including agrochemical active ingredients, preservatives, food flavorings, fragrances, and inert ingredients. He has also reviewed chemical portfolios and overseen Good Laboratory Practice (GLP) acute toxicity testing. Additionally, he has supported exposure studies to refine consumer goods risk assessments. In all, he has acquired broad expertise in inhalation toxicity and exposure stemming from consumer goods. This experience, coupled with an in-depth knowledge of regulations related to biocidal products, has allowed him to support registration efforts for multiple pest control products in the US and EU. In conjunction with this support, Dr. Klaren has served on several task forces instituted to expand the robust safety profiles, through ongoing toxicity testing and governmental registrations, of the pyrethroid class of insecticides.
Dr. Klaren has experience in systematic review and distilling essential concepts from published literature via weight-of evidence (WoE) evaluations. Furthermore, he has expertise on ascertaining the reliability and relevance of publications to advance prioritization initiatives with a keen understanding of available critical appraisal tools. He has also worked with in vitro and in vivo data sets for subsequent incorporation into mode-of-action or adverse-outcome pathway frameworks, with a particular focus on endocrine disruption (ED). In conjunction with the evaluation of the literature, Dr. Klaren has conducted ED potential assessments following current guidance—in particular, the ECHA/EFSA ED guidance, and has also conducted screening-level ED assessments on a variety of chemicals and components of consumer goods.
Dr. Klaren has expertise with new-approach methods, highlighted by research into alternative approaches to animal testing by developing and qualifying high-throughput in vitro assays utilizing organotypic cultures. Such work has been demonstrated in multiple publications on fit-for-purpose assay development and model system evaluation. Additionally, Dr. Klaren has worked on leveraging new-approach data as well as traditional toxicity data to inform adverse outcome pathway (AOP) development. In all, Dr. Klaren has extensive experience working with a diversified portfolio of toxicity data to incorporate into a risk assessment.
More recently, Dr. Klaren has investigated the external stressors that may impact the traditional risk assessment approach as noted by recent cumulative impact/risk assessment guidance. Specifically, he has explored the impact of societal and other non-chemical stressors on the potential increased chemical susceptibility of disadvantaged communities. Such work has included evaluation of National Health and Nutrition Examination Survey (NHANES data, literature scoping reviews for available studies, and AOP assessments to understand how, and the potential extent to which, such stressors can alter chemical-mediated toxicity.
Dr. Klaren has a strong record of communication through publications and presentations. He is active in the Society of Toxicology, supports younger career toxicologists via guest lecturing and mentoring, and has received multiple awards from employers and in academia. Additionally, Dr. Klaren became a Diplomate of the American Board of Toxicology in the fall of 2021.