Chemistry - Chemical Industry Expert Witnesses: 20

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Gary D. Fletcher, PhD,  is the Founder and Principal Consultant at RnDDx Solutions LLC, a consulting firm founded in 2015, focused on Industrial Mechanical Engineering and Biomedical Engineering and Research and Product Development.  In his 30 years of experience, he has been co-inventor on 23 patents for devices and methods in blood collection and processing.

Litigation Support - Dr. Fletcher has subject matter expertise in Medical Device Mechanical Engineering and subject matter expertise in Medical Devices for blood and specimen collection and sample processing for in vitro diagnostics, point of care diagnostics, and therapeutics, including glucose monitoring. He serves as an expert witness in patent infringement cases involving medical device and diagnostic biomedical engineering, blood collection, separation, fluidic preparation, glucose monitoring, and cell therapy preparation devices.

Dr. Fletcher offers patent litigation services to law firms and lawyers supporting medical device and diagnostic industry clients, who need physical science and mechanical and biomedical engineering expertise for District Court, PTAB, and ITC patent cases. As an industry consultant, his ideal clients are R&D, product development, and innovation leaders in startup, emerging, and established medical device and diagnostic companies, who face product development and competitive challenges.

Areas of Expertise:

Dr. Fletcher is an entrepreneurial executive with expanding R&D roles in business, technology, and new product development leadership and execution, building and guiding teams in both Fortune 500 and startup companies. With a PhD in physics from Yale, he has a proven record of leadership in creating innovative new businesses and products in healthcare, medical devices, diagnostics, life, materials, and optical sciences.

Paul E. Rosenfeld, M.S., Ph.D., is the Founder and Principal Scientist of RoseyFields LLC and a nationally recognized forensic environmental scientist and plaintiff expert witness. Over 25 years, his work has spanned complex toxic-tort and class-action litigation — including MTBE, PFOA/PFAS, asbestos, FELA railroad exposure, air-dispersion modeling, epidemiology, toxicology, industrial contamination, and pesticide exposure matters — with an aggregate case value of approximately $14 billion, and he has been deposed approximately 150 times in 31 states.

Litigation Support

Dr. Rosenfeld's opinions are based on established scientific methodologies, quantitative exposure models, peer-reviewed scientific literature, published technical methods, and reproducible calculations that can be independently evaluated and tested, providing a rigorous scientific foundation for expert opinions under Daubert and related standards for the admissibility of scientific evidence. He has authored and contributed to books and technical publications concerning environmental contamination, exposure assessment, and risk evaluation and has applied these scientific methods in expert reports, litigation, depositions, regulatory proceedings, and trial testimony.

Methodologies & Scientific Approach

Dr. Rosenfeld's air dispersion modeling work applies EPA-approved and peer-reviewed models, including AERMOD, CALPUFF, and ALOHA, to reconstruct historical emissions, source attribution, and community-level exposure pathways. His exposure and dose reconstruction methods integrate environmental sampling data, regulatory exposure factors, and published toxicological and epidemiological literature to quantify human exposure to chemicals including benzene, PFAS/PFOA, TCE, hexavalent chromium, and crystalline silica, among others. Each methodology is applied transparently, allowing the underlying calculations, data inputs, and modeling assumptions to support general cuasation opinions. 

Publications & Court Qualifications

Dr. Rosenfeld has authored six books and dozens of peer-reviewed publications on environmental contamination and risk assessment. He has been qualified as an expert under Daubert and analogous standards in federal and state courts nationwide reflecting consistent application of scientifically defensible methodologies under prevailing standards for expert testimony admissibility.

Areas of Expertise:

George Schiro is a DNA Technical Leader - Forensic Scientist. His duties include incorporating the DNA Advisory Board (DAB) standards, accountability for the technical operations of the lab, conducting DNA analysis using the 13 STR core loci and Y STR in casework, DNA research, forensic science training and crime scene investigation.

Mr. Schiro has worked over 3500 cases and has qualified as an expert over 175 times in 31 Louisiana parish courts, Arkansas, California, Florida, Mississippi, Missouri, Nevada, New York, Texas, West Virginia, federal court, U.S. court-martial, and two Louisiana city courts. Has also consulted on cases in 29 states.

Qualified as an Expert in the Following Areas:

Professor Christopher J. Tennant, PhD, CIH, has over 40 years of experience in the field of Environmental Health and Industrial Hygiene. He is Board Certified in the Comprehensive Practice of Industrial Hygiene. Dr. Tennant is currently President, CEO, and Principal Consultant at San Joaquin Environmental, in Fresno California, where he consults with Federal, State, County, City, various public agencies, and private industry sectors from public housing to Aerospace. His services are available in all 50 US States and the United Kingdom.

Dr. Tennant also serves as Professor Emeritus for the Department of Public Health at Fresno State University where he's taught Environment Health, Industrial Hygiene, and Occupational Health and Safety for 35 years at both undergraduate and post graduate levels.

Litigation Support - Dr. Tennant has been retained by numerous insurances companies and law firms on various Industrial Hygiene matters throughout the US, including workers compensation, property damage, personal injury, and wrongful death. He has testified as an expert witness in Federal Court, Superior Court, and Workers Compensation Appeals Board over 100 times. He's been deposed many more times. 

Areas of Expertise: