Environmental Chemistry Expert Witnesses: 7

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:

Paul E. Rosenfeld, M.S., Ph.D., is the Founder and Principal Scientist of RoseyFields LLC and a nationally recognized forensic environmental scientist and 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:

RedSpire, LLC delivers end-to-end Exposure Science and Occupational Epidemiology services to support data-driven decision making. RedSpire's expert analysis is fast, deep, and cost-effective and their technology amplifies their expertise. RedSpire's scientists turn strategy into actionable outcomes.

Litigation Support - Ideal clients are attorneys or firms involved in toxic tort litigation, particularly those with occupational exposures, who are interested in a technology-forward approach to streamline the expert witness work. RedSpire is interested in clients who want to transform how the industry integrates science into legal cases, through more systemic applications of technology that can bring the science of a case to the forefront in ways that reduce the reliance on expensive and time-consuming expert witness work.

Dr. Kristen Good is an Epidemiologist and Certified Industrial Hygienist (CIH) with over 15 years of scientific background and experience in risk assessment, toxicology, exposure assessment, and environmental sciences, across academia/research, private industry, and government sectors. She is passionate about identifying data-driven, scientifically-supported solutions to complex problems - and communicating those solutions to stakeholders and the public. She has a Ph.D. in Environmental Health with an epidemiology concentration from Colorado State University, a Master's degree in Environmental Management, toxicology focus, from Duke University, and a B.S. in Biology from Boston College.

Dr. Good has served as the leading technical authority in occupational health and indoor air quality at the Colorado Department of Public Health and Environment (CDPHE) since 2020. She manages the state’s indoor air quality improvement programs and occupational health surveillance and response initiatives. She regularly advises partners, workplace managers, and the general public on health and safety regulations and best practices, PPE and administrative controls to reduce exposures/safety risks, employer liabilities related to occupational health and safety, and post-incident response related to a variety of occupational health and safety concerns and scenarios.

From 2020-2022, Dr. Good led the Industry Response Team of the state’s COVID-19 pandemic response. She was responsible for advising on workplace outbreak prevention, investigation, and response for hundreds of workplace outbreaks, and employer responsibility across a wide variety of industry sectors. She also worked with the Governor’s Office and other state agencies on COVID-19 guidance and policy development.

Areas of Expertise:

Dr. Nicholas Good, Co-Founder and Exposure Science Lead, is an Aerosol Scientist with over 20 years of experience in Scientific Instrument Development, Evaluation, and Deployment. He has worked across academia, research, and private industry in aerosol exposure sciences, indoor air quality, and environmental health. Dr. Good focuses on bridging emerging technology—both hardware and software—from the research laboratory into solutions for practical real-world problems. He holds a Ph.D. in Atmospheric Science from Manchester University and a B.S in Physics from The University of Manchester.

Dr. Good provides consulting services supporting clients' needs in occupational health and safety, exposure assessment, and environmental health issues—with particular focus on asbestos and benzene exposure reconstructions. In addition to his role with RedSpire, Dr. Good owns Good Science LLC (2019-present), which provides specialized environmental consulting services primarily for legal clients, and co-founded CloudSci LLC (2023) a company commercializing airborne particle measurement technologies for research and related markets.

Since 2017, Dr. Good has served as Research Scientist at Colorado State University (first in the Department of Environmental & Radiological Health Sciences, and now in the Department of Civil and Environmental Engineering), leading research on air quality and human health with emphasis on indoor air quality, building performance, bioaerosols, and novel health effects of air pollution.

Areas of Expertise:

Dr. Gavin McMeeking, Chief Executive Officer & Co-Founder, is an Aerosol Scientist with over 20 years of experience in Scientific Instrument Development, Evaluation, and Deployment. He has worked across academia, research, and private industry in atmospheric chemistry, cloud physics, aerosol measurements, and environmental health. Dr. McMeeking focuses on bridging emerging technology—both hardware and software—from the research laboratory into solutions to practical real-world problems. He holds a Ph.D. and M.S. in Atmospheric Science from Colorado State University and a B.A. in Earth and Planetary Science from UC Berkeley.

Dr. McMeeking leads the company's strategic direction and client services. He co-founded CloudSci LLC (2023), which commercializes airborne particle measurement technologies for research and related markets. Previously, he held leadership roles at Handix Scientific LLC, first as a Senior/Principal Scientist (2015-1010) and then as VP of Research & Development (2020-2022), and worked as a Scientist/Sales Specialist at Droplet Measurement Technologies (2012-2015). He has advised governmental organizations including the Department of Energy, National Science Foundation, and NASA on topics ranging from instrument development, atmospheric measurement techniques, black carbon aerosol impacts, wildfire emission characterization, and technology translation.

Areas of Expertise:

View RedSpire, LLC's Consulting Profile.

Mark O. Barnett, PhD, PE, BCEE has over 30 years of national and international Environmental Engineering and Science experience in industry, government, and academia ranging from water supply and sanitation in rural communities to nuclear waste disposal. He is currently a Professor of Environmental Engineering in the Department of Civil and Environmental Engineering at Auburn University.

Litigation Support - Dr. Barnett has served as an environmental expert witness-expert consultant on cases in administrative, federal, and state courts ranging from permit applications to toxic tort lawsuits. He has written expert reports, filed affidavits, been deposed, and given testimony. Further, he has extensive litigation experience from his service as an administrative judge with the Nuclear Regulatory Commission. Writing samples, transcripts, and references are available upon request.

Areas of Expertise:

Background Experience - Dr. Barnett is a licensed professional engineer and a board-certified member of the American Academy of Environmental Engineers and Scientists. His technical research focuses on the chemical processes controlling water quality and contaminant behavior in natural and engineered systems. He has been a principal or co-principal investigator on seventeen grants totaling over $12 million, and he has published over fifty peer-reviewed journal articles, several book chapters, and a book that collectively have received over three-thousand citations.

Dr. Barnett has a B.S. in Chemical Engineering and an M.S. in Environmental Engineering from the University of Tennessee and a Ph.D. in Environmental Sciences and Engineering from the University of North Carolina. He has taught fundamental and applied courses in environmental and aquatic chemistry; water and wastewater treatment; environmental engineering principles and design; and sustainable design and development.

Randal Hill, PhD, Thought leader in chemistry, materials science and intellectual property.  Award winning PhD scientist with 30+ years in applied chemistry.  Visiting Scientist at MIT for 5 years to foster silicone-based nanotechnology projects.  Holder of 69 issued patents.  Author of Silicone Surfactants book and 60 articles.  Served as Patent Science Advisor to grow patent portfolio by 1500%.  Deveoped display for Amazon Kindle.  Readily adapts expertise to new problems.  Served as adunct faculty at Stanford and University of Minnesota.  Organized two international symposia.  Invited speaker at Gordon Conference and four international colloid meetings.  Associate Editor of Journal of Surfactants and Detergents.  Involved member of American Chemical Society, Society of Petroleum Engineers, American Physical Society, and American Oil Chemists Society. Awards  include 3 Dow Corning Technical Achievement Awards, as well as the AOCS Samuel Rosen Award for Surfactant Chemistry.  

Experience includes fire-fighting foams, well fluids, adhesives, silicone defoamers, formulation of household and personal care products, applications of silicone surfactants, silicone-based nanotechnology for soldier protection, development of pigments for electronic displays.

Background Experience - Dr. Hill began his career at a major detergent company followed by developing sugar-based surfactants. He went on to spend 20 years with Dow Corning developing personal care applications for silicones, leading the pigment science group at E Ink developing the next generation of color electrophoretic ink displays, and leading the Formulation Development group at Flotek to expand the product line by 300% and grow the patent portfolio by 1400%.

Dr. Hill is now known for his work on silicone surfactants, especially for his work on super wetting. During his time as MIT Visiting Scientist with Dow, he also initiated work on silicone-based superhydrophobic surfaces, which led to a publication that has since been cited nearly 1,500 times.

Dr. Hill is the author of 60 publications, including an authoritative book entitled, Silicone Surfactants. He is a highly awarded inventor with accolades that include 3 Dow Corning Technical Achievement Awards, as well as the 2017 AOCS Samuel Rosen Award for Surfactant Chemistry.

Rudolph Johnson, PhD, is a Chemical Toxicologist with over 20 years of experience in analytical chemistry and toxicological investigations. Dr. Johnson's past experience includes directing the (1) clinical toxicology network, LRN-C, at the Centers for Disease Control and Prevention and (2) the Military Exposures Research Program at the US Department of Veterans Affairs. Currently, he serves as the Director of the Wisconsin State Laboratory of Hygiene and has a faculty appointment at the University of Wisconsin-Madison School of Medicine and Public Health, Department of Pathology.

Dr. Johnson focuses on two specialty areas:

(A) Toxicology: He offers causation opinions connecting dose, analytical detection, and biomarker findings to determine whether and to what extent an individual was exposed to a chemical or toxin.  The chemical or toxin may be inhaled, ingested or injected. This includes drug and alcohol testing.

(B) Laboratory Testing: He critiques or defends laboratory testing methodology, chain-of-custody, and quality assurance practices. He is an expert at evaluating conflicting testing data between two labs.

Litigation Support - Dr. Johnson works with plaintiff and defense litigation attorneys on toxic tort, product liability, and environmental and occupational exposure cases requiring causation analysis. He supports criminal defense and plaintiffs reviewing drug exposures (opioids, fentanyl analogs, polypharmacy) and alcohol testing. This includes chain-of-custody, and quality practices. Conflicting or inconsistent laboratory data, especially between multiple laboratories, is a specialty area of Dr. Johnson because he previously directed multiple clinical toxicology labs.

Dr. Johnson detects, quantifies, and interprets chemical and toxic exposure in human clinical samples. He is skilled in translating investigative information into causation opinions, connecting dose, biomarker significance, and clinical outcome—for poisoning, occupational, environmental, and mass-casualty toxicology cases.

Areas of Expertise:

Mark Franklin has over 28 years of experience in Environmental, Health, and Safety Management, Training and Consulting-across many industries, including construction, manufacturing, chemical, pharmaceutical and others. Mr. Franklin has applied industry experience in chemical emergency response, hazardous waste management, safety and environmental program management, OSHA regulatory compliance, and management program auditing (safety, quality, environmental).Mr. Franklin is a highly experienced, dynamic trainer in over 80 individual training topics.

Litigation Support - Mr. Franklin owns the Cove Acre expert witness practice. He leverages his years of experience in Occupational Health and Safety management, consulting, and training for his expert witness clients. He has investigated over 150 incidents, including serious injuries, fatality, chemical spills, and equipment and facility damage. Mr. Franklin's services are available to attorneys representing plaintiff and defendant. Mr. Franklin provides site review, thorough reporting, depositions, and trial testimony as needed.

Areas of Expertise:

Mr. Franklin is a dynamic and engaging trainer who can take often-complicated Occupational Health and Safety regulations and explain them so everyone in the audience can understand the meaning and intent. For deposition, in front of a Jury, or in front of a full conference room, his professional approach, calm demeanor, and organized presentation style ensure a thorough understanding for all. 

Reviewing regulations and their interpretations, researching industry and regulatory-body accepted best practices, reading peer-reviewed publications, and applying years of experience in general industry and the construction industry are all tools Mr. Franklin utilizes to provide thorough, reliable, and organized expert opinion reports.