meet our
dedicated team.
Jenn Sahmel, PhD, CIH, CSP, FAIHA
Founder and Managing Principal Scientist
Dr. Sahmel is a certified industrial hygienist, a certified safety professional, a Fellow of the American Industrial Hygiene Association (FAIHA), and a Research Fellow of the Exposure Science and Sustainability Institute at the University of Minnesota, with over 20 years of experience in human health risk assessment and workplace health and safety.
Dr. Sahmel has significant experience in exposure assessment practice and methodologies, exposure reconstruction, health risk decision making, OSHA regulatory issues, and safety management systems.
Dr. Sahmel's areas of expertise include comprehensive exposure and risk assessment strategies, exposure reconstruction, qualitative and quantitative dermal exposure assessment methods, industrial hygiene state of knowledge, Bayesian decision analysis, U.S. EPA exposure assessment tools, Proposition 65 health risk assessment, product stewardship and sustainability issues, industrial hygiene monitoring and data analysis, safety and occupational health management methods, and safety leadership.
Dr. Sahmel has been involved in characterizing exposure to a variety of chemicals and products for both occupational and consumer product exposure scenarios in a variety of circumstances including for government, academia, law firms, non-profit associations, and private companies. These substances include asbestos, talc, solvents, benzene, gasoline, flame retardants, wood dust, phthalates, lead, beryllium, silica, vinyl chloride, paints/coatings, boiler water treatments, organic solvents, abrasive blasting agents, mercury, arsenic, carbon monoxide, and others.
Shannon Gaffney, PhD, MHS, CIH, FAIHA
Senior Principal Scientist
Dr. Gaffney is an environmental health scientist with a wide range of experience in industrial hygiene, exposure assessment, and human health risk assessment. She has been involved in researching, measuring exposure, reconstructing dose and exposure, and assessing risk to consumers, communities, and workers exposed to a variety of chemicals, such as asbestos, diacetyl, benzene, hydrogen sulfide, trichloroethylene (TCE), tetrachloroethylene (PCE), perchlorate, formaldehyde, arsenic, methanol, beryllium, dioxins/furans, polychlorinated biphenyls (PCB), polycyclic aromatic hydrocarbons (PAH), n-nitrosodimethylamine (NDMA), glycol ethers, pesticides, lead, cadmium, cobalt, copper, chromium, nickel, sensory irritants, radionuclides, mold, and silica.
Dr. Gaffney has reviewed and contributed to the research behind setting occupational and environmental exposure limits. In addition, she has researched and assessed employer, distributor, and manufacturer responsibilities related to a variety of products and in regard to compliance with federal and state-level standards promulgated by the U.S. Occupational Safety and Health Administration (OSHA), Environmental Protection Agency (EPA), and California’s Office of Environmental Health Hazard Assessment (OEHHA). Recently, Dr. Gaffney has been involved in helping organizations respond to the COVID-19 pandemic while maintaining operation or re-opening operations by assisting with strategies to minimize the risk of SARS-CoV-2 infection. In addition to participating on professional task forces and committees, Dr. Gaffney sat on the board of directors of the American Conference of Governmental Industrial Hygienists and currently serves on the Editorial Review Board for the Journal of Occupational and Environmental Hygiene.
Scott Dotson, PhD, CIH, DABT
Principal Scientist
Dr. Dotson is a Principal Scientist with ~20 years of experience in toxicology, industrial hygiene, human health risk assessment, and occupational health and safety. This experience includes employment as a health scientist by the Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health (NIOSH) for over a decade. As a health scientist for NIOSH, Dr. Dotson relied on his knowledge of toxicology and industrial hygiene to critically evaluate occupational hazards and develop recommendations that served as the basis of NIOSH policies, scientific-decision making strategies, and tools. He has conducted assessments to characterize the risk of adverse health effects associated with exposures to a diverse range of chemicals (e.g., particulates/aerosols, organic solvents), exposure routes (e.g., inhalation, dermal, or multiple routes), and scenarios (e.g., occupational, environmental, and consumer scenarios). These assessments have relied on various approaches, such as systematic reviews, weight-of-evidence analysis, and data integration, in addition to inhalation dosimetry.
Dr. Dotson is a certified industrial hygienist (CIH) and a Diplomate of the American Board of Toxicology (DABT). He obtained a M.S. from Murray State University in Occupational Safety and Health with an emphasis in industrial hygiene and a Ph.D. in toxicology and risk assessment from the University of South Florida. He is actively involved in several professional organizations, such as the American Industrial Hygiene Association (AIHA), Product Stewardship Society, and Society of Toxicology (SOT). In 2023, he became a member of the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) committee.
Tony Cappello, PhD, REHS
Principal Scientist
Dr. Tony Cappello is an epidemiologist and public health practitioner with over 18 years of experience in a variety of scientific, leadership, and academic roles. He has experience and interest in applying epidemiological concepts to assess human health risks related to infectious diseases, chronic health conditions, and environmental and consumer product exposures. He has led various state and local public health risk assessments, conducted numerous outbreak investigations, and developed actions and strategies in response to, and in anticipation of novel public health concerns. Dr. Cappello is practiced in applying epidemiological methods to inform scientific-based decision making, including using statistical analysis, public health surveillance, and published literature to identify and assess human health risks.
Dr. Cappello’s experience includes serving as the Director of Disease Control and Public Health Response for the State of Colorado and as Colorado’s State Environmental Epidemiologist. Prior to this, he was the Public Health Director for the Northeast Colorado Health Department, and in 2014 he was appointed by the Governor of Colorado to the State Board of Health where he served as Board President from 2015 to 2017. Since 2012, he has been an Adjunct Professor teaching and writing graduate level courses in epidemiology, environmental health, and public health leadership and ethics. He holds PhD in Public Health Epidemiology, a Master of Public Health (MPH), a B.S. in Environmental Health, an Executive Certificate in Business Administration, and he is a Registered Environmental Health Specialist (REHS).
Brooke D. Simmons, MPH, CIH
Principal Scientist
Ms. Brooke Simmons is an environmental health scientist and certified industrial hygienist (CIH) with over 15 years of professional experience in industrial hygiene, exposure assessment and human health risk assessment. She has a wide range of experience, including researching, measuring exposure, reconstructing dose and exposure, and assessing risk to consumers and workers exposed in occupational settings, from consumer products, in the home, and in the environment to a variety of chemicals and agents including asbestos, talc, benzene, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), dioxins, trichloroethylene (TCE), tetrachloroethylene (PCE), formaldehyde, hexane, cadmium, copper, arsenic, mercury, nickel, lead, silica and mold. She has also investigated the health risks associated with heat and noise in occupational settings.
Ms. Simmons is experienced in determining contaminants of potential interest and designing industrial hygiene sampling protocols for various agents and settings. She has evaluated historical and contemporary compliance with applicable federal and state-level standards and regulations established by the U.S. Occupational Safety and Health Administration (OSHA), Environmental Protection Agency (EPA), and California’s Office of Environmental Health Hazard Assessment (OEHHA). Further, she has been involved with assisting organizations in responding to the COVID-19 pandemic by assisting with strategies to minimize the risk of SARS-CoV-2 infection.
Heather Avens, PhD, MS, CIH
Managing Risk Assessment Scientist
Dr. Heather Avens is a Managing Risk Assessment Scientist with over 12 years of experience in human health risk assessment. She is a Certified Industrial Hygienist with a PhD and MS in chemical engineering and a BA in biochemistry and molecular, cellular, and developmental biology.
Heather's primary areas of expertise include industrial hygiene, exposure assessment, risk assessment, indoor exposure modeling, outdoor air dispersion modeling, dermal exposure modeling, accident analysis, probabilistic techniques, and data analysis. She is also skilled at designing, conducting and analyzing exposure simulation studies.
She has estimated exposure and risk associated with a variety of substances including asbestos, silica, solvents, gasoline, benzene, polyaromatic hydrocarbons, asphalt, hydrogen sulfide, styrene, lead, cadmium, and phosphorus.
Heather has used her expertise to address a variety of exposure scenarios including occupational exposures, consumer use of products, exposures to bystanders, take-home exposures experienced by household contacts of workers, community exposures, industrial accidents, explosions, and spills.
Amber Banducci, MPH
Managing Risk Assessment Scientist
Amber is a Managing Risk Assessment Scientist with a Master’s of Public Health degree, and a BA in Integrative Physiology and Ecology and Evolutionary Biology. Her academic training includes epidemiology, biostatistics, environmental and occupational health, public health policy and law, immunology, human physiology, and endocrinology.
Amber has experience in exposure and risk assessment, U.S. health and safety regulatory issues, and data analysis. She also has experience performing exposure and risk assessments for consumer products regarding Proposition 65 and other regulatory compliance.
Amber’s work has included evaluating exposures, risks, and/or regulations in occupational and consumer use scenarios for cosmetic talc, asbestos, vinyl chloride, benzene, and heavy metals in various products and settings. She has also conducted comprehensive research related to regulatory aspects of U.S. respiratory protection programs and hearing protection program. Additionally, some of her research has also included potential exposures associated with historical use of cosmetic talc, heavy metal exposure from the consumption of apple juice, occupational and therapeutic radiation exposures, wood dust exposures, and BTEX exposures associated with hydraulic fracturing and crude oil cleanup operations.
Tyler Ferracini, MS, CIH
Managing Risk Assessment Scientist
Tyler is a Managing Risk Assessment Scientist with over 12 years of experience in exposure and risk assessment. He is a Certified Industrial Hygienist with a MS in Toxicology and a BS in Environmental Health and Radiological Science. His primary academic training and areas of expertise include toxicology, industrial hygiene, exposure and risk assessment, biostatistics, occupational/workplace health and safety, and epidemiology.
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Tyler has experience in exposure and risk assessments associated with occupational settings and consumer products. Further, he is knowledgeable in areas regarding product stewardship and sustainability practices, industrial hygiene monitoring and data analysis, and regulatory compliance.
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Tyler’s work has included evaluating exposures, risks, and/or regulations in occupational and consumer use scenarios for a variety of chemicals including but not limited to asbestos, talc, trichloroethylene (TCE), silica, formaldehyde, benzene, diacetyl, fly ash, and foundry dust. His research has included potential exposures associated with the historical use of asbestos, exposures related to dust within steel foundries, fly ash and silica exposures related to environmental spills. Additionally, he has performed reviews pertaining to the application of industrial hygiene practices in various industries, and performed a cross-sectional analysis of reported corporate environmental sustainability practices by companies across 26 industrial sectors.
Josh Maskrey, CIH
Managing Risk Assessment Scientist
Josh is a Managing Risk Assessment Scientist with over ten years of experience in exposure and risk assessment. He is a Certified Industrial Hygienist with a BS in Chemical Engineering. His training and areas of expertise include industrial hygiene, quantitative exposure assessment and modeling, human health risk assessment, air modeling, occupational safety, statistics and probabilistic modeling techniques, chemical engineering, organic chemistry, inorganic chemistry, and thermodynamics.
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Josh maintains an exposure and risk assessment practice focused on pragmatic problem-solving for clients with occupational health and safety needs. He has expertise in the design of occupational health assessments with both measurement and modeling components. He has demonstrated success in the design and execution of exposure simulation studies for both volatile liquid and particulate agents. He has experience developing regulatory compliance programs and has provided scientific support to expert witnesses in litigation projects.
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Josh’s project work has included occupational, consumer and environmental exposure assessments. He has experience evaluating exposures to physical and chemical agents including, but not limited to: asbestos, benzene, carbon monoxide, caustic/acidic vapors, chlorinated solvents, diacetyl, ethanol, formaldehyde, glycol ethers, diesel exhaust, diesel and gasoline fuels, hexanes, silica, toluene, xylenes, ionizing radiation, noise, and excessive heat. His research interests include quantification of consumer and non-occupational exposures to toxic chemicals, design of simulation studies to recreate historical exposure scenarios, improvement of exposure assessment methodologies, and improving the effectiveness of hazard and risk communication methods.
Alex Riordan, MPH
Senior Risk Assessment Scientist
Alex Riordan, MPH is a Senior Risk Assessment Scientist with eight years of experience in epidemiology, risk assessment, and data analysis/biostatistics. He has a Master of Public Health (MPH) in epidemiology from the University of Michigan, and a BS in Movement Science from the School of Kinesiology at the University of Michigan. His primary areas of training and expertise include occupational and environmental epidemiology, cancer epidemiology, large-scale systematic reviews and meta-analyses, biostatistics/data analysis, exposure and risk assessment, and industrial hygiene.
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Alex has experience in epidemiological evaluations of causality, specifically for exposures in occupational settings and/or through use of consumer products. Further, he has experience conducting exposure and risk assessments associated with occupational settings and consumer products. He is knowledgeable in areas regarding industrial hygiene sampling and regulatory standards.
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Alex has performed numerous meta-analyses, including but not limited to topics of asbestos, talc, solvents, pesticides, medical devices, pharmaceuticals, and nutrition. He has additionally conducted several case-control and cohort studies using cancer registry and national health survey databases. His research has included evaluating mesothelioma risk from non-occupational exposure to asbestos (both environmentally and domestically), evaluating lymphohematopoietic and breast cancer risk from exposure to ethylene oxide, risk of lung cancer from acrylonitrile exposure, characterization of airborne cosmetic talc exposure, and characterization of dermal and airborne glyphosate exposure. Additionally, he has performed longitudinal evaluations to ascertain secondary cancer risk following radiation and chemotherapy treatments. Moreover, Alex’s work has included evaluating exposures, risks, and/or regulations for a diverse array of chemicals.
Liz Best, MS
Senior Risk Assessment Scientist
Liz is a Senior Risk Assessment Scientist with almost 15 years of experience in consulting, nine of which have focused on epidemiology, risk assessment, and data analysis/biostatistics. She has a Masters degree in epidemiology from the University of Colorado, and a Bachelors degree in marine science with a chemistry emphasis from the University of San Diego. Her primary areas of training and expertise include occupational and community epidemiology, statistical analyses, and environmental chemistry.
Liz is experienced in epidemiological evaluations of causality, using Bradford Hill guidelines, specifically for exposures in occupational settings (e.g., firefighters) and/or through use of consumer products (e.g., talc) and cancer (e.g., mesothelioma, kidney cancer, prostate cancer). Additionally, she has experience with descriptive statistics, systematic reviews including study quality evaluations, and meta-analyses. For example, Liz has calculated descriptive statistics for survey data collected on PAH urine metabolites and substance use. She has also performed a systematic review, pooled analysis, power analysis and confidence interval function analysis to examine the association between cosmetic talc exposure and mesothelioma. Her experience with meta-analyses involved evaluating the risk of lymphohematopoietic and breast cancers from occupational exposure to ethylene oxide. Further, Liz has experience with environmental and industrial hygiene sample collection and analytical data validation. For example, she recently collected air samples at a mortuary in an effort to determine the concentration of formaldehyde, and the analytical data were used for compliance with government organization monitoring programs, data gap analysis, background contamination level analysis, human health risk assessments, and ecological risk assessments.
Risk Assessment Scientist
Fian is a Risk Assessment Scientist with over seven years of experience in exposure and risk assessment. She has a Bachelor of Science in Environmental Toxicology from the University of California, Davis. Her primary areas of training and expertise include toxicology, exposure and risk assessment, industrial hygiene, and workplace health and safety.
Fian has experience assessing risk and exposure in workplaces, communities, and consumers associated with various substances including, but not limited to, asbestos, benzene, heavy metals, herbicides, and PFAS. Her research has included evaluating exposures to historical uses of asbestos; glyphosate from foods and dietary styles; and metals, particulates, volatile organic compounds (VOCs), inorganic acids, and phthalates in consumer products. She has assisted with the execution and analysis of exposure simulation studies, as well as prepared site-specific safety protocols (i.e., COVID-19 Prevention Program) to support COVID-19 reopening efforts. In addition, she has experience providing technical support for expert witnesses in litigation matters.
Sarah Brown, MS
Risk Assessment Scientist
Sarah is a Toxicologist and Risk Assessment Scientist with ~six years of experience in toxicology, exposure science, and risk assessment. She has a MS in environmental health with a specialty in toxicology from the University of Massachusetts Amherst, and a BS degree in biology from Saint Michael’s College. Her primary areas of training and expertise include toxicology, exposure and risk assessment, and occupational health.
Sarah’s work has involved evaluating potential risks associated with consumer and occupational exposures to a variety of chemicals, including asbestos, nitrosamines, talc, phthalates, 1,2-dichloropropane (PDC), parabens, polybrominated diphenyl ethers (PBDEs), flavoring ingredients, and harmful or potentially harmful constituents (HPHCs) in electronic nicotine delivery systems (ENDS) and oral nicotine products. She has conducted human health risk assessments examining potential risks associated with trace contamination of N-nitrosodimethyamine (NDMA) and N-nitrosodiethylamine (NDEA) in pharmaceutical products. She has also advised pharmaceutical companies in selecting appropriate comparators on which to estimate interim Acceptable Intakes (AI) for novel nitrosamines detected in various drug products. In addition, she has provided technical support to various manufacturers of alternative tobacco products in their submission of FDA Premarket Tobacco Applications. These projects involved the evaluation of potential health effects, and characterization of potential toxicological hazards associated with exposure to flavoring ingredients and HPHCs used in ENDS and in oral nicotine products. Her work has also involved conducting qualitative and quantitative exposure assessments regarding occupational, non-occupational, and bystander exposures to asbestos-containing products. She also assisted in a project where she evaluated potential health risks associated with reoccupying a commercial building that contained vermiculite fireproofing. In addition, she has experience in providing technical support in various class-action litigation matters in the United States and Canada related to nitrosamines, asbestos, and ENDS.
Deanna Badger, MS
Risk Assessment Scientist
Ms. Deanna Badger is a Risk Assessment Scientist with five years of experience in exposure and risk assessment. She holds an M.S. in Chemical Engineering from Carnegie Mellon University and a B.S. in Environmental Sciences from Duke University. Her training and areas of expertise include toxicology, chemistry, chemical engineering, human health and ecological risk assessment, and exposure assessment and modeling.
Deanna has experience estimating occupational, consumer, and environmental exposures to various substances, including asbestos, talc, N-nitrosamines, heavy metals, flavoring ingredients, chlorinated solvents, and flame retardants. She additionally has experience in providing technical support to expert witnesses in toxic tort litigation matters. Her research has included evaluating the potential health risks of 1,1,2-trichloroethane to avian species as well as mercury, lead, cadmium, and arsenic contamination in baby foods to children. She is interested in quantifying human and ecological exposures to toxic chemicals, developing methodologies to screen chemicals for hazards, and designing and executing simulation studies.
Hannah Mazzotta, MPH
Associate Risk Assessment Scientist
Hannah is an Associate Risk Assessment Scientist with Insight Exposure & Risk Sciences in the Boulder, Colorado Office. She completed her Master of Public Health degree at the Colorado School of Public Health with a concentration in epidemiology. She also holds a Bachelor of Science degree in neuroscience with a concentration in cellular and molecular neuroscience from Colorado State University. Her primary training and areas of expertise include biochemistry, industrial hygiene, exposure assessment, risk assessment, nanotechnology, and epidemiology.
Hannah has experience conducting and contributing to exposure and risk assessments primarily with asbestos, talc, benzene, and solvents in occupational and non-occupational settings. She has experience conducting industrial hygiene and environmental health research, including systematic reviews and simulation studies. Her graduate research was concentrated on occupational exposure and regulations of nanomaterials and aerosols, including prenatal nanoparticle exposure, use of nanomaterials in PPE, and quantitative exposure assessment of nanoparticle-containing consumer products.
Kathy Chan
Associate Risk Assessment Scientist
Ms. Kathy Chan is an Associate Risk Assessment Scientist with four years of experience in exposure and risk assessment. She holds a B.S. in Public Health with a concentration in Nutritional Biochemistry from the University of North Carolina at Chapel Hill. Her training and areas of expertise include exposure modeling and assessment, human health risk assessment, toxicology, biochemistry, and industrial hygiene.
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Kathy has experience with characterizing occupational, consumer, community, and environmental exposures to chemicals including heavy metals, phthalates, food flavoring compounds, vinyl intermediates, and asbestos in various products and settings. She has evaluated chemical exposures in the context of regulatory compliance, such as for California’s Proposition 65, as well as for expert support in litigation matters. Her research has included screening assessments for phthalates in clothing materials, as well as analytical method development to characterize the environmental fate and transport of tire and roadwear particles. Kathy’s current research interests include development of quantitative exposure models, particularly related to chemicals in consumer products and foods, application of exposure and risk assessment methods to product stewardship practices, and improving risk communication for workers and communities.
Ashmitha Seshadri
Assistant Risk Assessment Scientist
Ashmitha is an Assistant Risk Assessment Scientist with a Bachelor of Science in Environmental Health from the University of Washington. Her primary areas of academic training include occupational safety, chemical sampling & analysis, hazardous waste management, toxicology, and biostatistics.
Ashmitha has experience working in environmental health and safety roles in research settings. Her work has focused on incident response and investigation, hazard communication, environmental policy compliance, and chemical handling. She has performed routine chemical air sampling to quantify workplace exposures to formaldehyde, chloroform, and other hazardous chemicals used during laboratory activities. Throughout her academic career, her primary research topics centered around occupational exposures and health outcomes for various chlorinated hydrocarbons such as PCBs, organochlorine pesticides, and methylene chloride. She also has previous work experience in healthcare administration where she was involved with training staff and volunteers on safe patient care, infection prevention, and emergency hospital procedures.
Stephanie Tack, MPH
Assistant Risk Assessment Scientist
Stephanie is an Assistant Risk Assessment Scientist with a Master of Public Health degree from the University of Vermont Larner College of Medicine. She also holds a B.S. in Microbiology and Molecular Genetics from the College of Agriculture and Life Sciences at the University of Vermont. Her areas of academic training include epidemiology, biostatistical analysis, infectious disease, and population environmental health.
Stephanie has experience in adolescent and maternal population health. She previously worked as a clinical research assistant at the Children’s Hospital of Philadelphia on the Moderna COVID-19 randomized control trials along with the MOMI-Vax observational study investigating COVID-19 antibody transfer between mothers and infants. Her graduate work concentrated on evaluating the risk of risky sexual behavior in rural youth communities. Other previous research topics include the microbiome-gut-brain axis and HIV syncytia. Stephanie has worked in multiple microbiology and molecular genetics laboratories on the University of Vermont campus. She also interned at the Children’s Hospital of Philadelphia as a Data Analyst on COVID-19 Community Vaccine Clinics Team.
Laurie Armijo, aPHR
Business and Office Manager
Laurie is an experienced office administrator with a demonstrated history of working in industries such as environmental services, software development, home loan mortgages, clinical trials, higher education and more.
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Her areas of expertise include administrative professional support in litigation, sales, administration, software documentation, accounting, recruiting, H.R., and process scheduling.
Kate Butkins
Accounting and Operations Coordinator
Kate is an accounting professional with over 15 years of experience in scientific consulting and professional services.
Her professional experience includes managerial accounting, billing specialist, and project accounting.