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May 16, 2024

At a time of declining DABT certification across the industry, J.S. Held welcomes a team of 20 notable toxicologists, health scientists, and industrial hygienists.


JERICHO, NY -- May 16, 2024 -- Global consulting firm J.S. Held, proudly celebrating 50 transformative years, expands toxicology consulting services and welcomes a team of 20 toxicologists, health scientists, industrial hygienists, data analysts, and library services staff to provide health-based and environmental services involving public health, exposure, risk assessment, and characterization. The additions to J.S. Held, an ENR Top 200 Environmental Consulting Firm, create one of the world’s largest toxicology consulting teams, further strengthening the firm's ability to advise in diverse and increasingly complex engagements.

According to data published by the American Board of Toxicology®, the pool of Diplomate of the American Board of Toxicology® (DABT) credentialed toxicology experts has declined by more than 35% from a total of 4,068 certified since the DABT examination was first administered in 1980 to January 1, 2023, when there were only 2,631 currently certified DABT toxicologists worldwide. At a time of declining DABT certification across the industry, J.S. Held welcomes notable toxicologists, health scientists, and industrial hygienists, including:

Dallas Cowan, Ph.D., CIH, DABT, is a Board-Certified Toxicologist (DABT) and Certified Industrial Hygienist (CIH) with more than 15 years of consulting experience in occupational toxicology, industrial hygiene, exposure, and human health risk assessment. His industrial hygiene and safety experience includes a variety of exposure assessment techniques, qualitative and quantitative fit testing for respiratory protection programs, development of safety bulletins, and preparation and conduct of safety briefings regarding permit-required confined space entry, fall protection, respiratory protection, and personal protective equipment. Dr. Cowan has provided technical and litigation support on various projects involving exposure and human health risk assessment of chemicals in various occupational, environmental, and consumer product settings. Dr. Cowan has published over 25 abstracts, book chapters, and peer-reviewed papers on industrial hygiene, consumer products safety, environmental exposure, toxicology, and risk-related topics.

Patrick Kerzic, Ph.D., DABT, is a Board-Certified Toxicologist (DABT) with extensive experience in designing, conducting, and analyzing mechanistic and human-subject research studies and human health risk assessments. He previously served as a Staff Toxicologist with the California Environmental Protection Agency, overseeing human health risk assessment activities for over 100 sites contaminated with solvents, metals, and other hazardous materials. He also served as a writer and reviewer for the Safer Consumer Products program, which aims to encourage the substitution of hazardous compounds with safer alternatives, and was a Scientific Director for a laboratory, conducting research and clinical studies into blood diseases, including leukemia and lymphoma, and overseeing molecular biology and toxicology programs. He has published over 35 abstracts and peer-reviewed papers in toxicology and hematology.

Angie Perez, Ph.D., CIH, is a Principal Toxicologist, Senior Technical Fellow of Industrial Hygiene, and a Certified Industrial Hygienist. She has more than 20 years of experience in human health risk assessment, toxicology, exposure and risk assessment, sampling and analysis, and emergency response. Dr. Perez specializes in quantitative exposure reconstruction of occupational and environmental toxicants, human health risk assessment, and evaluation of general causation relationships between chemical exposure and disease. Her expertise includes evaluation of potential health effects of occupational and community exposures to per- and polyfluoroalkyl substances, volatile organic compounds, metals, sulfur compounds related to odors and industrial releases, and evaluation of risk of injury or death associated with consumption of drugs and alcohol. Dr. Perez regularly contributes to scientific, peer-reviewed literature with more than 50 published articles and abstracts on topics related to toxicology and industrial hygiene.

David Fung, Ph.D., CIH, is a Certified Industrial Hygienist (CIH) with ten years of professional experience in consulting. He received his Ph.D. in Industrial Hygiene, where his principal research was on the emission of and exposure to particulate matter generated during the operation of cooking ranges. In his career, Dr. Fung has also conducted research on the emission of and potential exposure to ultrafine particles and nanoparticles from various indoor and outdoor sources, failure rates of hip implants, and potential exposure to asbestos from the use of cosmetic talc. Dr. Fung’s technical expertise includes industrial hygiene surveys, exposure assessments, and indoor air quality assessments. Additionally, Dr. Fung has provided consulting services in litigation involving potential exposure to asbestos, silica, talc, mold, volatile organic compounds (VOCs), and other chemical agents.

Thales Cheng, MPH, CIH, is a Certified Industrial Hygienist (CIH) with consulting experience in industrial hygiene, exposure assessment, toxicology, human health risk assessment, and emergency response. Mr. Cheng has managed litigation projects and provided support for cases related to asbestos, underground storage tanks, and consumer exposures from products such as e-cigarette devices. He has also been involved in the assessment of occupational, non-occupational, and environmental exposures to asbestos, talc, formaldehyde, acetaldehyde, acrolein, and VOCs in a variety of settings.

J.S. Held toxicologists evaluate exposure, contamination, and toxicity to determine adverse effects on human health or the environment. Together with their team, the experts advise on health-based and environmental matters involving public health, exposure, contamination, toxicity, risk assessment, and characterization. They work with clients to develop and implement risk mitigation strategies, conduct forensic investigations, provide regulatory assessments and deliver expert services for arbitration and litigation matters.

John Peiserich, Environmental Health & Safety (EHS) Practice Leader, commenting on the expansion of the team, adds, “I am thrilled that this very unique collection of toxicology and health science experts has identified J.S. Held as a platform to optimize their professional development and to perform important work on behalf of clients around the globe.”

Engaged by US and multinational corporations, utilities, developers, government organizations, insurance professionals, construction professionals, and the legal community, J.S. Held EHS experts consult on matters involving the environment, human health and safety, and regulatory compliance. Learn more about the dedicated and entrepreneurial experts who help transform J.S. Held, explore our story, and celebrate this momentous milestone, our 50 & Forward celebration, with us at

About J.S. Held

J.S. Held is a global consulting firm that combines technical, scientific, financial, and strategic expertise to advise clients seeking to realize value and mitigate risk. Our professionals serve as trusted advisors to organizations facing high stakes matters demanding urgent attention, staunch integrity, proven experience, clear-cut analysis, and an understanding of both tangible and intangible assets. The firm provides a comprehensive suite of services, products, and data that enable clients to navigate complex, contentious, and often catastrophic situations

More than 1,500 professionals serve organizations across six continents, including 81% of the Global 200 Law Firms, 70% of the Forbes Top 20 Insurance Companies (85% of the NAIC Top 50 Property & Casualty Insurers), and 65% of the Fortune 100 Companies.

J.S. Held, its affiliates and subsidiaries are not certified public accounting firm(s) and do not provide audit, attest, or any other public accounting services. J.S. Held, its affiliates and subsidiaries are not law firms and do not provide legal advice. Securities offered through PM Securities, LLC, d/b/a Phoenix IB, a part of J.S. Held, member FINRA/ SIPC or Ocean Tomo Investment Group, LLC, a part of J.S. Held, member FINRA/ SIPC. All rights reserved.
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