Toxicology Consultants & Assessment Specialists, LLC

Toxicology Consultants and Assessment Specialists, LLC


The TCAS team during a recent toxicological case review
The TCAS team during a recent toxicological case review.[a]

Founded in 1988 and led by Dr. William R. Sawyer, Toxicology Consultants and Assessment Specialists is a group of dedicated professionals working diligently to achieve stellar results for its clients by objectively assessing toxicological evidence and providing impartial reports and testimony. TCAS has provided toxicological services to individual plaintiffs and defendants, corporations, local law enforcement, attorney generals, governmental agencies and organizations covering a broad spectrum of interests. Clients range from individuals to multi-national Fortune 500 companies with a historical ratio of approximately 45% to 55%, defendants and plaintiffs respectively.

With a strong reputation for precision and a passion for excellence, TCAS works closely with every client to ensure that key concerns are addressed and deadlines are met with the highest quality of work. Through application of clear communications, pragmatic planning and timely follow-through, TCAS has achieved an outstanding success record in cases involving hazardous substances, alcohol, heavy metals, pharmaceuticals, consumer products, public health, toxic torts and other highly specialized areas.

Forensic toxicology and toxic exposure investigations include analytical protocol and referencing of environmental and autopsy material for analyses. Environmental and occupational health risk assessments include site-specific assessments, dose measurement and causation determination. Final work products include scientific method references, method validation, forensic chain-of-custody and written reports. Reports and expert witness testimony have been provided in 34 states to date and in countries as far away as Hong Kong.

Armed with a broad experience base, extensive technical resources and productive support relationships with some of the best laboratories and scientists in the country, TCAS is well positioned to provide superior toxicological assessments, forensic analyses and a wide range of specialized consulting services. Our case study archives highlight just a few of the more than 600 cases for which TCAS has been retained during its 28 year history.


Dr. William R. Sawyer, Chief Toxicologist

Dr. William R. Sawyer, Expert Toxicologist

Dr. William R. Sawyer holds a doctorate in toxicology from Indiana University School of Medicine. He has more than 34 years of extensive experience in public health and forensic toxicology with specialized expertise in causation analyses (for plaintiff and defense) involving alcohol, drugs-of-abuse, pharmaceuticals, herbal products, dioxins, solvents, heavy metals, crude oil, radionuclides/NORM and other substances. Dr. Sawyer has testified at trial and/or deposition in 34 states and has provided international expert testimony as far away as Hong Kong. As a skilled scientist and communicator in the area of toxic tort, Dr. Sawyer provides services to governmental agencies, corporations and select plaintiffs and defendants. Dr. Sawyer currently serves as the Chief Toxicologist for TCAS and also has been an Assistant Professor (adjunct) for 23 years with the Department of Medicine, Upstate Medical University, Syracuse, New York. Dr. Sawyer has approximately 14 years experience as a licensed clinical and environmental laboratory director in several states. Dr. Sawyer is a distance swimmer for the Gulf Coast Swim Team and has completed several "Swim Around Key West" races, most recently in just under six hours (2nd place award). He is also a triathlete with the distinction of being a four-time Ironman. He loves to fish and SCUBA dive in northern New York State and the Gulf of Mexico.

Funmi Afelumo, M.S., Environmental Toxicologist

Funmi Afelumo, M.S., Environmental Toxicologist

Funmi Afelumo began working with Dr. Sawyer in March 2015. He recently graduated from the State University of New York - College of Environmental Sciences and Forestry (SUNY-ESF) with his master's degree which focused on Plant Science and Biotechnology. His graduate research project was in the field of phytoremediation; specifically, increasing plant tolerance to toxic heavy metal exposure. He has been performing research in the field of phytoremediation and environmental health and safety since 2010. He has presented his research at several conferences including those for environmental health and biotechnology. Funmi particularly enjoys that at TCAS he is able to apply his scientific knowledge and reasoning to help solve problems and make society better. When not reading scientific journals and other literature, Funmi enjoys volunteering for communiy services and hiking through New York State's beautiful parks.

Jennifer Clark, Office Manager

Jennifer Clark, Reseacher & Office Manager

Jennifer Clark began working with Dr. Sawyer in 2007 after spending the previous 18 years as a full-time mom. With a background as a legal assistant prior to the birth of her two daughters, Jen spends a considerable amount of her time interfacing with clients as well as making sure all aspects of active cases are moving forward smoothly. She can also often be found working on report preparation and editing so that information is presented concisely and succinctly and always on time. Jen loves a challenge and the fact that no two days at TCAS are the same. When not at the office, Jen enjoys gardening, reading, camping and solving puzzles. She is also a huge fan of the Adirondack Mountains of upstate New York and spends several weeks each summer exploring the woods and lakes with her husband, Jim, and golden retriever, Gracie.

Bonnie Serling, M.S., Chemical Engineering

Bonnie Serling, Technical Associate

Bonnie Serling joined TCAS in September of 2015. Her college education began at Clarkson University where she earned her BS in chemical engineering. She continued her education at University of Rochester earning an MS degree (also in chemical engineering) for her research in microcirculatory hemodynamics. Bonnie enjoys reading, solving word and number puzzles and tackling home improvement projects. She and her husband, Steve, have three children. As an enthusiast of problem-solving, Bonnie enjoys investigative research and seeking answers to the challenging cases here at TCAS.

Carol Sawyer, Accounting Manager

Carol Sawyer, Accounting Manager

Carol Sawyer serves as accounting manager and bookkeeper for TCAS. By training, Carol is a dental hygienist and graduate from Indiana University School of Dentistry. She also has prior training and work experience in an accounting firm as a file room clerk and has managed company records since its inception in 1988. Carol enjoys preparing specialty foods, volunteering in her church and community, visiting barrier island beaches, reading and just being outdoors.

Our Trusted Support Staff


TCAS is very much a "hands-on" organization. Dr. Sawyer can frequently be found directly at the center of the information-gathering process. In these cases, exposure information may be only partially available or even missing entirely. In such cases the team takes proactive steps to gather evidence and compile on-site investigative data. This is an important aspect of developing an exposure reconstruction — particularly if a case involves demonstrating or refuting alleged causation.

The snapshots below show the team collecting water, soil, sediment and dust samples related to recent contamination cases. Samples were labeled, catalogued, stored and prepared for shipment to various laboratories for analyses under carefully-documented forensic chain-of-custody procedures (in accordance with U.S. EPA methodology).


Dr. Sawyer was recently retained to serve as lead expert in a major toxicological case in Hong Kong.

A Message from Dr. William R. Sawyer
Chief Toxicologist, TCAS, LLC

A message from Dr. William R. Sawyer, Expert Toxicologist

"TCAS takes pride in our client relationships. You can expect open lines of communication, thorough reports and opinions and prompt, timely attention to address your questions and concerns. It is our goal to always meet and exceed our clients' expectations!"

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This is an informational and instructional website devoted to toxicology. It presents both original and edited public-domain content compiled as a useful educational resource. References and footnotes have been included wherever possible and image sources have been cited where appropriate. Although most pages can be printed or downloaded as PDF files (and we encourage you to make constructive use of our information), this website is copyrighted and material may only be reproduced and/or distributed with prior permission from TCAS, LLC.