TERA Staff

TERA's professional staff bring diverse backgrounds to the development of risk assessment values and methods. To find contact information for an individual TERA staff member, click on the name below. General questions or comments can be sent to tera@tera.org.

Click a name for biography and contact information.

Valerie Ayers, Administrative and Purchasing Assistant

PHONE: 513-558-7947
FAX:  (513) 558-7199
EMAIL:  Ms. Ayers


Ms. Ayers joined TERA in 2006. She brings with her a wealth of administrative experience.

Michael L. Dourson, Ph.D., DABT, ATS, Director

LinkPHONE: (513) 558-7949
FAX:  (513) 558-7199
EMAIL: Dr. Dourson


Dr. Dourson is the President of Toxicology Excellence for Risk Assessment (TERA), a nonprofit corporation dedicated to the best use of toxicity data in risk assessment.  TERA develops partnerships among government, industry and other interested groups to address risk assessments of high visibility, such as formaldehyde, perchlorate, chloroform, and soluble nickel, and cooperative ventures such as the Voluntary Children’s Chemical Exposure Program (VCCEP), the International Toxicity Estimates for Risk (ITER) database (available at the National Library of Medicine’s ToxNet), and the Alliance for Risk Assessment (ARA).  Before founding TERA in 1995, Dr. Dourson held leadership roles in the U.S. Environmental Protection Agency as chair of US EPA's Reference Dose (RfD) Work Group, charter member of the US EPA's Risk Assessment Forum and chief of the group that helped create the Integrated Risk Information System (IRIS).  
Dr. Dourson received his Ph.D. in Toxicology from the University of Cincinnati.  He is a Diplomate of the American Board of Toxicology and a Fellow of the Academy of Toxicological Sciences and Society for Risk Analysis.  
Dr. Dourson has served on or chaired numerous expert panels, including peer review panels for US EPA IRIS assessments, US EPA’s Risk Assessment Forum, TERA’s International Toxicity Estimates for Risk (ITER) independent peer reviews and consultations, FDA’s Science Board Subcommittee on Toxicology, the NSF International’s Health Advisory Board, and SOT’s harmonization of cancer and non-cancer risk assessment.  He served as Secretary for the Society for Risk Analysis (SRA) and has held leadership roles in specialty sections of SRA and SOT.  He is currently on the editorial board of two journals.  Dr. Dourson has published more than 100 papers on risk assessment methods, has co-authored over 100 government risk assessment documents, and has made over 100 invited presentations.


-       Ph.D., Toxicology, University of Cincinnati (1980)

-       Certified, American Board of Toxicology (1985, 1990, 1995, 2000, 2005, 2010)

-       Fellow, Academy of Toxicological Sciences (2007)

-       Fellow, Society for Risk Analysis (2009)


Bernard K. Gadagbui, M.S., Ph.D., DABT, Global Outreach Manager

LinkPHONE: (513) 558-7943
FAX:  (513) 558-7199
EMAIL: Dr. Gadagbui


Dr. Gadagbui has over 14 years of professional experience in environmental health, risk assessment, and toxicology. He is involved in diverse projects to assess occupational and environmental toxicants and carcinogens, which require an in-depth understanding of mechanisms and modes of toxicity, current methods for assessing toxicological outcomes, and interpretation of toxicological and human health data.  Dr. Gadagbui specializes in evaluation of adequacy of EPA uncertainty factors for database deficiency in protecting against effects on reproduction, hazard ranking and screening methods for chemicals in support of product hazard assessments, consumer safety assessments, and the threshold of toxicological concern approach for developmental and/or reproductive toxicants.


Prior to joining TERA in 2004, Dr. Gadagbui held toxicologist positions at the University of Florida and the Bureau of Pesticides of the Florida Department of Agriculture and Consumer Services (FDACS). At the University of Florida, Dr. Gadagbui was involved in teaching and conducting research in environmental health, developing provisional health-based groundwater and surface water criteria for data-poor chemicals and mixtures of chemicals for use in deriving cleanup goals, and reviewing human health and site remediation risk assessments. At FDACS, he served as the Scientific Evaluation Section Staff Coordinator for the Bureau of Pesticides and conducted and coordinated toxicological reviews and assessments of data submitted for the support of pesticides registration. 


Dr. Gadagbui has been active in toxicology societies where he has held or currently holds leadership positions. These include Toxicologist of African Origin (TAO) Specialty Interest Group of the Society of Toxicology (SOT) (President, 2008-2009), Ohio Valley SOT (OVSOT) (Councilor), African Society of Toxicological Sciences (ASTS) (Vice President), and Ohio Chapter of the Society for Risk Analysis (OSRA) (Secretary).


Dr. Gadagbui has received numerous awards for his work.  Most recently, he led a project that received honorable mention in 2010 for the Alice Hamilton award for top risk assessment work at NIOSH. He also led a team of TERA scientists that won the 2010 Risk Reduction Achievement Award from the Alliance for Chemical Safety, a regional professional organization with a mission to promote public understanding and involvement in chemical risk management.


- B.S. with honors, University of Ghana, Biochemistry with Chemistry (1985)

- M.S., University of Bergen, Norway, Biochemistry (1992)

- Ph.D., University of Bergen, Norway, Environmental Health & Aquatic Toxicology (1996)

- Certified, American Board of Toxicology (2007)



Lynne Haber, Ph.D., DABT, Associate Director of Science

PHONE: (513) 558-7631
FAX:  (513) 558-7199
EMAIL: Dr. Haber

Dr. Haber joined TERA in 1998 and currently is the Associate Director, responsible for strategic direction of our science portfolio, training and overall quality initiatives at TERA.  She has 18 years of experience in development of assessment documents and in risk assessment methods development, including consideration of mechanism/mode of action. She was the lead author of more than 30 major documents for multiple EPA offices, other government agencies, and private sponsors, and has been a coauthor or reviewer of 100’s more. 


She has served as a panel chairperson or panel member for scientific peer reviews organized by TERA, EPA, and other U.S. and foreign government agencies.  She has also served on two panels for the NAS/NRC.  Dr. Haber is active in communicating her findings to the broader scientific community through participation in professional societies, routine publication of her work, authoring book chapters, service as an editorial reviewer for scientific journals,  and through presentation of invited lectures.  She has experience in benchmark concentration/ benchmark dose (BMC/BMD) modeling and categorical regression modeling, and served as a peer reviewer for EPA’s BMD modeling guidelines.  Other methods development work includes the combination of PBPK and BMD/BMC modeling in the development of RfDs and RfCs; research into methods for improving the scientific basis for uncertainty factors; consideration of mode of action in cancer risk assessment; toxicology issues related to potentially susceptible populations (e.g., children’s risk); and use of biomarker data in risk assessment. 


She served as chair-elect, vice president and councilor of the SRA Dose-Response specialty group and as an officer of the SOT Risk Assessment Specialty Section (RASS), and is a Diplomate of the American Board of Toxicology.  She is one of the lead teachers for TERA’s Dose-Response Assessment Boot Camp, developed a course on issues related to children’s risk assessment, and presents specialized courses to diverse groups of risk assessors and at professional society meetings.

- B.S., Chemistry, University of California, Los Angeles (1983)

- Ph.D., Molecular Biology, Massachusetts Institute of Technology (1990)

- Certified, American Board of Toxicology (2004, 2009)

Andrew Maier, Ph.D., CIH, DABT, Co-Director

PHONE: (513) 558-2407
FAX:  (513) 558-7199
EMAIL: Dr. Maier


Dr. Maier has 18 years of professional work experience in the areas of environmental health, occupational hygiene, and toxicology. He currently serves as the Chair of TERA Fellows Program and I serve as an Associate Professor in the Division of Environmental and Occupational Hygiene, Department of Environmental Health, College of Medicine at the University of Cincinnati. Active research includes methods in occupational risk assessment, including derivation of occupational and environmental exposure limits, cumulative risk assessment, and field validation studies of exposure models.


Dr. Maier completed his Ph.D. in toxicology with research interests in the molecular mechanisms of toxicity. Dr. Maier is also currently serving as a Toxicology Fellow with the National Institute for Occupational Safety and Health.  He is a Diplomate of the American Board of Toxicology (DABT).  

- B.S., Natural Resources, Ball State University (1988)
- M.S., Industrial Health, University of Michigan (1989)

- Ph.D., Toxicology, University of Cincinnati (2000)
-Certified, Comprehensive Practice, American Board of Industrial Hygiene (1994)

-Certified, American Board of Toxicology (2004)

Jeanelle Martinez, Ph.D., Toxicologist

PHONE: (513)-558-7965
FAX:  (513) 558-7199
EMAIL: Dr. Martinez

Dr. Jeanelle Martinez has more than 15 years experience in toxicology and risk assessment. Her expertise includes DSC_0065.JPGanalysis of health risks for chemical warfare agents and pesticides.  Dr. Martinez has published 16 manuscripts in peer-reviewed scientific journals and has authored summary training guides for both chemical and biological agents. The guidance documents included background information, exposure limits, expected health effects after exposure, personal protection equipment recommendations, hazard reduction, and cleanup information.  

While at the US Environmental Protection Agency (EPA), Dr. Martinez was a Toxicologist for the National Decontamination Team for 9 years providing scientific and technical Human Health Risk Assessment support for the Office of Emergency Response in OSWER.  Dr. Martinez also provided planning and preparedness to the US EPA Regions On-Scene Coordinators for possible terrorist-related activities, and major events such as natural disasters. Field support was provided by developing and/or reviewing clearance and risk evaluation for a variety of contaminated sites.  Her interests included the development of strategies to ensure successful decontamination of sites and the use of models to evaluate exposures and obtain clearance for environmental chemicals such as chemical warfare agents.    


As a postdoctoral fellow, Dr. Martinez performed research in the Laboratory of Computational Biology and Risk Analysis under the National Toxicology Program at National Institute of Environmental Health Sciences/NIH. Dioxin exposure to human lung epithelial cells was investigated by Toxicogenomic analysis. Dose response gene expression changes were measured with microarray analysis and specific gene expressions confirmed by RT-PCR. The results showed network activation of signal transduction pathways indicative of disruption of cell growth and differentiation.  The changes in cell growth and differentiation were validated and the signaling pathway analysis was used in the development of predictive mathematical models.


Dr. Martinez received her doctoral degree from the Program of Toxicology, Graduate School of Biomedical Sciences at The University of Texas, M.D. Anderson Cancer Center, Department of Experimental Gynecology/Oncology. Her doctoral research focused on neonatal exposure to estrogenic compounds. Individual OH-PCBs tested were estrogenic and tumorigenic and the data supported the hypothesis that chemicals can act differently and unexpectedly when exposure occurs during critical windows in the development of the female reproductive tract.

- 1984 -1989​    Bachelor of Science in Biology, New Mexico State University, Las Cruces NM
- 1991 - 1993​   Master of Science in Biology, New Mexico State University, Las Cruces NM
- 1993 - 1999​   Doctor of Philosophy, The University of Texas, M.D. Anderson Cancer Center, Houston TX


Patricia M. Nance, M.Ed., M.A., Science Outreach & Initiatives Leader

LinkPHONE: (513) 558-1054
FAX:  (513) 558-7199
EMAIL: Ms. Nance

Ms. Nance joined TERA in February 2002 and is currently the Science Outreach & Initiatives Leader.  Ms. Nance leads a broad range of TERA’s corporate communications activities, supports new initiatives, develops news and highlights milestones. She drives communication initiatives for TERA’s marketing and community activities (website, science meetings, community service activities, science education initiatives etc.).  Ms. Nance also works on projects involving risk assessment and human health sciences, including writing oral and inhalation toxicological reviews, acute and chronic health assessments, and summaries, leading and participating in teams for scientific reviews and report preparation, and developing work plans and budgets.  She has 17 years experience in environmental science, risk assessment, project management, writing, and instructional design; as well as in developing, maintaining and support of a variety of databases. 


Ms. Nance manages two standing offer contracts with Health Canada.  The contracts cover services that include peer reviews and consultations, oral and inhalation toxicological assessments, risk assessment regulatory guidance development, toxicology support and training.  She has managed over 70 letter reviews for Health Canada that involved the review of oral and inhalation toxicology for non-cancer and cancer assessments.  She also currently manages education and training projects at TERA, including a week long intensive course in dose-response risk assessment.  Ms. Nance has been involved in reviews and analysis of acute and chronic toxicity studies, including animal, mechanistic, epidemiological, and developmental studies.  She has participated in the development of databases used for compiling an array of toxicological data.  Ms. Nance has gathered, validated, and screened human health data under contracts with U.S. EPA, Health Canada, Department of Defense, and private companies.


She contributes to a variety of projects at TERA.  She has been the meeting coordinator for numerous meetings at TERA.  Some of her functions included developing meeting webpages, meeting packet information, and handling logistics.  Ms. Nance managed 7 non-lethal projects that developed Human Effectiveness and Risk Characterizations (HERCs) reports on numerous non-lethal weapons.  She has also prepared detailed meeting notes for many scientific and technical meetings, including peer reviews.  Ms. Nance writes toxicological summaries for incorporation into material safety data sheets (MSDSs). 

Before joining TERA, Ms. Nance worked as the Project Manager/Technical Information Specialist for International Consultants, Inc. and IntelliTech Systems, Inc.  Ms. Nance reviewed and edited provisional human health toxicity papers, prepared literature searches for human health toxicity information, obtained supporting material for use in developing surrogate chemicals by quantitative structural analysis relationship (QSAR) analysis, and maintaining a variety of databases for tracking information requests, chemical information, superfund site activity, and QSAR surrogate predictions.

She is currently a member of the Society for Risk Analysis (SRA), the Alliance for Chemical Safety (ACS), and the Ohio Chapter of the Society for Risk Analysis (OSRA).  She is curhas active roles in SRA, serving as a member Conferences & Workshops Committee, a co-Chair for the Workshops at the Annual Meeting (WAM) Subcommittee, a member of the Communications Committee, and the Organizing Committee for the SRA’s World Congress.


B.S., Geology, Marshall University (1995)
- M.Ed., Education - Instructional Design & Technology, University of Cincinnati (2000)

- M.A., English - Professional Writing, University of Cincinnati (2002)

Ann Parker, B.S., Biologist

PHONE: (513) 558-1053
FAX:  (513) 558-7199
EMAIL: Ms. Parker


Ms. Parker joined TERA in 2003 as a Research Assistant and was promoted to an Associate Environmental Scientist in 2005.  In this capacity, Ms. Parker works with senior scientists on various projects providing toxicology support, data validation, and technical support.  As a research assistant Ms. Parker has gathered, validated, and screened human health data for the various projects.  She has experience in BMDS and CatReg modeling, critical effect analysis, and dose-response or concentration-response evaluation of animal toxicity studies for use in risk assessment.  Ms. Parker was the lead for a project that updated the methodology for derivation of IDLH values which was used to develop new or revised IDLH value documents. She managed all aspects of development from literature searches to final delivered product for 100+ chemicals.  Ms. Parker was also key author for many of these chemicals, screening and reviewing the available scientific literature, identifying key studies and appropriate endpoints, applying ten Berge equation for exposure duration adjustment, and determining the appropriate safety factors.


- P.S.M. candidate, Integrative Pharmacology and Toxicology, Michigan State University, present
- B.S., Natural Sciences, (Chemistry minor) University of Cincinnati, 1998
- A.A.S., Veterinary Technology, University of Cincinnati, 1994


Jacqueline Patterson, M.En., Associate Director for Programs

PHONE: (513) 558-7908
FAX:  (513) 558-7199
EMAIL: Ms. Patterson

Jacqueline Patterson is the Vice President of Toxicology Excellence for Risk Assessment (TERA) and also is responsible for the development and operations of TERA's independent peer review program.  Ms. Patterson specializes in human health risk assessment and organizes and manages expert panels to evaluate toxicology and risk issues for government and private sponsors.  She has over 25 years experience in environmental science, risk assessment, convening peer reviews and consultations, project management, database development and support, and report writing.  She has developed and managed databases for the U.S. EPA and TERA, has written and reviewed reports on risk assessment and related topics, and developed training courses and materials for various audiences.  She has provided technical support to work groups, committees, and symposia for government and private sponsors.  Ms. Patterson organizes workshops and independent peer reviews and peer consultations for public and private sponsors.  She also provides analysis, writing, technical review, and editing of assessment documents and other reports to insure accuracy, soundness of conclusions, and appropriateness of language to intended audience. 

Ms. Patterson is well-recognized for her work in developing processes for peer input and review of risk assessments and has published a number of papers on the topic.  Through the development and management of TERA's independent peer review and peer consultation program she has managed over 100 detailed scientific reviews on diverse risk assessment and analysis topics for government, industry, and non-profit sponsors.  These reviews bring together international groups of experts to evaluate and judge risk assessment documentation for both public and private sponsors.  Ms. Patterson successfully manages complex peer input projects using her abilities to distill multifaceted risk science matters into logical sets of issues.  Ms. Patterson was the Project Manager of a 6-year cooperative agreement with the U.S. EPA that developed peer consultation processes for risk assessment, and organized a dozen peer consultations for assessments prepared under the Voluntary Children’s Chemical Evaluation Program (VCCEP).  She recently managed a collaborative effort of industry, government, academic and non-profit scientists to evaluate mode of action and dose-response approaches to nuclear receptor-mediated liver cancer.  Ms. Patterson also develops and reviews risk assessment documentation for TERA sponsors.  Recent projects involved an assessment of the risk from mercury released from broken compact fluorescent lamps, and development of a relative source contribution for RDX. 

Ms. Patterson joined TERA in its first year and has helped build the non-profit into a successful independent organization that currently employs over a dozen scientists who assess chemicals for human health and occupational risks; develop risk methods; and, review risk assessment, toxicology and epidemiology issues.  Before joining TERA, Ms. Patterson worked for twelve years for the U.S. EPA in the Office of Policy, Planning and Evaluation and the Office of Research and Development.  With EPA she planned and managed in-house and contractual activities for the Integrated Risk Information System (IRIS). Her responsibilities included development of the overall IRIS program, database development, user support, outside involvement, and cross-Agency coordination.

Ms. Patterson served on the National Research Council’s Committee on Ethical Issues in Housing-Related Health Hazard Research Involving Children, Youth, and Families.  She currently serves on the City of Cincinnati Environmental Advisory Council and has been involved in other local environmental initiatives, including the Hamilton County (Ohio) Environmental Priorities Project and the Cincinnati Climate Change Action Plan Committee.  She serves as the co-chair for the Annual Meeting Workshops subcommittee of the Society for Risk Analysis (SRA) and is a founding officer of the Ohio Chapter of SRA.  She is a full member of SRA and the Society of Toxicology. She has received numerous awards for individual and group efforts including the Alliance for Chemical Safety Risk Communication Award for her work and leadership in developing a peer consultation program for the Voluntary Children’s Chemical Evaluation Program; EPA medals for her work on development of IRIS, a decision system for developing regulatory policies, and establishment of an on-site child development center; and a Key Risk Award from Links2Go for development of ITER

- B. Phil., Interdisciplinary Studies, Miami University (1980)

- M.En., Environmental Sciences, Miami University (1984)



Judy Pollock, Financial Administrator

PHONE: (513) 542-7475, extension 12
FAX: (513) 542-7487
EMAIL: Ms. Pollock


 Ms. Pollock joined TERA in April 2002   In her role as TERA’s financial administrator, Judy is responsible for all aspects of TERA’s financial management.  Before joining TERA, Judy worked for several small businesses simultaneously as bookkeeper or business manager.  Her role in these companies included all facets of bookkeeping, general office administration and design and layout of business forms and publications.  She specialized in setting up small office accounting systems that were then maintained on a weekly basis.  Judy is very active in the community and is a member of the Northside Community Council, where she served as Council treasurer from 2000-2001.  Judy is currently pursuing a degree in accounting.


John Reichard, Ph.D, Toxicologist

PHONE: (513) 558-7946
FAX:  (513) 558-7199
EMAIL: Dr. Reichard


Dr. Reichard recently joined TERA and holds a dual appointment at the University of Cincinnati in the Department of Environmental Health. Dr. Reichard has doctoral degrees in Molecular Toxicology from the University of Colorado, and Pharmacy from the University of Kentucky. Dr. Reichard’s doctoral project in toxicology focused on the role of oxidative stress in liver disease with an emphasis on the kinetics and metabolism of reactive oxidative intermediates. Dr. Reichard has performed two postdoctoral fellowships: one at the University of Cincinnati where he characterized the interactions of arsenic-regulated transcription factors with gene promoters in human keratinocytes. This project included detailed analysis of gene expression, proliferation and skin cell differentiation. These studies laid the groundwork for subsequent epigenetic studies of dioxin and BaP. The second fellowship was performed at The Children’s Hospital Boston in conjunction with Harvard Medical School where Dr. Reichard investigated the effects of hypoxia on in vivo transcriptional gene regulation in the lungs. During these studies Dr. Reichard developed genomic approaches to investigate the convergence of transcription pathways on cytokine genes in lung endothelial cells. As part of TERA, Dr. Reichard is contributing his expertise in genomic research to support TERA’s effort to facilitate the application of next generation toxicology methods and approaches in risk assessment.


- B.S., Pharmacy and Molecular Biology, University of Wyoming (1992)

- Pharm.D., Doctor of Pharmacy, University of Kentucky (1996)

- Ph.D., Molecular Toxicology, University of Colorado (2004)


Reena Sandhu, Ph.D., DABT, Senior Toxicologist


PHONE: 905-338-1497

EMAIL: Dr. Sandhu


Dr. Sandhu is a pharmaceutical toxicologist with over 10 years of experience working in senior scientific or consulting roles in the pharmaceutical and biotechnology industries. Her expertise includes all aspects of support in these business sectors from drug discovery and development through to post-marketing product support. Dr. Sandhu is also an experienced medical writer and nonclinical data reviewer, having prepared or reviewed numerous successful regulatory documents including CTD summaries and overviews. She has also authored dozens of scientific publications and provided scientific review for in-license candidates and novel products. In recent years, Dr. Sandhu has worked as a toxicological risk assessor for pharmaceutical, personal healthcare and consumer product companies. As a toxicological risk assessor, she has conducted hundreds of safety assessments on issues that impact, or could potentially impact the safety, effectiveness and/or quality of finished product. A large part of this work has involved limit setting for both genotoxic and nongenotoxic impurities in raw materials or finished products. Prior to working in industry, Dr. Sandhu completed a PhD in Physiology at the University of Toronto, Canada and post-doctoral training in Cardiology at St. Michael's Hospital in Toronto. Throughout her training, she received multiple competitive research awards. She is also a Diplomate of the American Board of Toxicology.



Melissa Vincent, M.S., Associate Epidemiologist

LinkPHONE: (513) 558-7908
FAX:  (513) 558-7199
EMAIL: Ms. Vincent


Ms. Vincent joined TERA in 2007.  At TERA, Ms. Vincent provides senior scientists with research, technical, and statistical support on a wide array of projects. Ms. Vincent’s  focus is on integrating human health information with toxicology data to develop informed chemical risk assessments. Her work includes researching various chemicals to identify potential human health risks, identifying critical endpoints and points of departure for use in risk assessment, deriving safe values, regression modeling, and meta-analysis. Ms. Vincent is also experienced in dose-response evaluation and modeling, the use and development of weight of evidence methods, and development of screening tools for hazard identification and characterization.  She has designed and conducted meta-regression analyses and is continuing to expand her expertise in this area.


- B.A. Miami University, Zoology with a focus in Chemistry (2007)
- M.S. Epidemiology, University of Cincinnati (2013)


Alison Pequet nee Willis, M.Sc., Associate Ecotoxicologist

LinkPHONE: (513) 558-6179
FAX:  (513) 558-7199
EMAIL: Ms. Willis

Ms. Willis has 6 years of experience in environmental science and risk assessment. Her focus is human health and ecological risk assessment for exposure to chemicals and other stressors. Qualifications include, but are not limited to:


  • Human health risk assessment, including literature searching, study evaluation, point of departure selection, benchmark dose and other modeling, application of uncertainty factors, derivation of toxicity reference values, etc.;
  • Application of modeling software (RDDR and MPPD) to evaluate the impact of inhalation dosimetry adjustments on point of departure;
  • Evaluation of the impacts of single and multiple stressors on environmental receptors and humans;
  • Evaluation of the impact of PAHs singularly or in mixtures to aquatic endpoints;
  • Phototoxicity mechanisms and risk assessment to aquatic systems;
  • Extensive data review and evaluation in support of risk assessments.

Ms. Willis graduated from Antioch University with a Bachelors of Science with a focus in biomedical science.  She conducted undergraduate research on the effects of plasticizers on bacterial populations for her senior research thesis. After college, she conducted research at the Savannah River Ecology Laboratory (SREL) on the effects of gold nanoparticles in a benthic food web system. This research was able to show uptake of these particles into soil organisms.  Upon completion of that research, Ms. Willis began to work at Toxicology Excellence for Risk Assessment (TERA).


During her time at TERA, Ms. Willis has contributed to numerous technical projects.  She has completed training to use modeling and other software and has applied these techniques in chemical assessments. She has assisted on many projects through literature searches, data gathering and organization, assessment of government and private sector studies, publication of books and manuscripts, and data management/analysis. She has developed a broad understanding of how to use animal and human databases to assess risk, and has applied these skills to numerous assessments throughout her time at TERA.

While working at TERA, in addition to assigned project work, Ms. Willis began work towards a Master’s degree in ecotoxicology at Miami University and her thesis was awarded in May 2013. This research investigated toxicity of single and combined exposures to polycyclic aromatic hydrocarbons (PAH) and included the additional stressor of ultraviolet radiation resulting in phototoxicity to fish. Currently, Ms. Willis holds the co-chair position of the Ecological Risk Assessment Specialty Group (ERASG) for the Society of Risk Analysis (SRA). Her current work at TERA includes continuing to provide scientific support of key toxicological issues related to human health and the environment.



- B.S., Biomedical Science, Antioch University, 2007

- M.Sc., Zoology (Ecotoxicology), Miami University, 2013






TERA Visiting Scientists and Fellows Programs

TERA has developed both the Visiting Scientist and TERA Fellow Programs to encourage collaboration with others and to improve risk assessment practices.  Our program includes:

bullet Visiting Scientists are those engaged with TERA for a fixed period of time or on a defined project.  Project work may or may not be onsite at TERA’s Cincinnati office.  While visiting scientists are often senior, positions can also be considered for scientists who are beyond internship level, but for whom a period at TERA would be of mutual benefit. 

bullet TERA Fellows are senior scientists associated with TERA on a longer-term basis with ongoing scientific interactions. 


TERA Fellows and Visiting Scientists are not employees of TERA, but rather scientists who share TERA's mission and values and seek to improve the practice of risk assessment. TERA collaborates with Visiting Scientists and/or TERA Fellows on projects of mutual interest.    


In the past, scientists have worked with TERA and coauthored manuscripts or reports on a variety of topics, including methods for evaluating persistent and bioaccumulative chemicals, exposure assessment methods, dose-response modeling, mixtures assessment, and investigating the magnitude of adult-to-child toxicokinetic differences in inhalation dosimetry of gases. 


Individuals interested in either program should contact Dr. Andrew Maier.



TERA Fellows & Visiting Scientists

Andrew Maier, Ph.D., CIH, DABT, Chair


PHONE: (513) 558-2407
EMAIL: Dr. Maier


Dr. Maier has 18 years of professional work experience in the areas of environmental health, occupational hygiene, and toxicology. He currently serves as the Chair of TERA Fellows Program and I serve as an Associate Professor in the Division of Environmental and Occupational Hygiene, Department of Environmental Health, College of Medicine at the University of Cincinnati. Active research includes methods in occupational risk assessment, including derivation of occupational and environmental exposure limits, cumulative risk assessment, and field validation studies of exposure models.


Dr. Maier completed his Ph.D. in toxicology with research interests in the molecular mechanisms of toxicity. Dr. Maier is also currently serving as a Toxicology Fellow with the National Institute for Occupational Safety and Health.  He is a Diplomate of the American Board of Toxicology (DABT).  

- B.S., Natural Resources, Ball State University (1988)
- M.S., Industrial Health, University of Michigan (1989)

- Ph.D., Toxicology, University of Cincinnati (2000)
-Certified, Comprehensive Practice, American Board of Industrial Hygiene (1994)

-Certified, American Board of Toxicology (2004)

plusJohn P. Christopher, Ph.D., DABT, TERA Fellow


John P. Christopher, Ph.D., DABT., was named a TERA Fellow in 2009.  Dr. Christopher received his education at Georgetown University (B.S., 1967), Stanford University (M.A., 1972), and Oregon State University (Ph.D., 1979).  After working in contract laboratories for five years as a director of safety studies in animals, he came to California government in 1985.  He served as a risk assessor for pesticide registration, evaluation of toxicity of chemicals, and regulatory risk assessment for hazardous waste sites for four years, then worked in the private sector as an environmental consultant from 1989-1992.  He returned to the California Department of Toxic Substances Control (DTSC) in 1992, from which he is retiring in March, 2010.  Dr. Christopher’s principal duties at DTSC included regulatory review of risk assessments for hazardous waste sites, especially military bases.  He has been the internal expert at DTSC on biostatistics and analysis of ambient levels of metals.  Dr. Christopher has served on some 30 panels since 1997 as a peer reviewer for TERA , U.S. EPA , U. S. Department of Defense, and Health Canada .  Subjects for review included toxicity criteria for industrial and environmental chemicals, bioavailability of metals, children’s risk assessment, and evaluation of non-lethal weapons.  In 2008, he led a successful team competing for a $900,000 grant from U.S. EPA on bioavailability of arsenic in soil from former mining lands.  Dr. Christopher is a member of the Society of Toxicology.  He is also a founding member and past President of both the Risk Assessment Specialty Section and Northern California Chapter of the Society of Toxicology.  He has received numerous service awards from DTSC, the Risk Assessment Specialty Section and the Northern California Chapter of SOT.  In 2007, he received a Lifetime Achievement Award for waste cleanup from the International Symposium on Contaminated Soil, Groundwater and Air.


Richard Hertzberg, Ph.D., TERA Fellow

Biomathematics Consulting
1932 Grist Stone Ct NE
Atlanta, GA




Richard Hertzberg, Ph.D. is a biomathematician who is internationally recognized for innovations and expertise in quantitative methods for environmental health risk assessment of chemical mixtures. Dr. Hertzberg has a B.S. in mathematics from Harvey Mudd College and a Ph.D. in biomathematics from the University of Washington. He retired from the U.S. Environmental Protection Agency in 2006 after working for 25 years as a Mathematical Statistician with EPA’s Office of Research and Development, National Center for Environmental Assessment. He is presently a visiting Associate Professor at Emory University, and on the graduate committee for one student at Emory and one student at Carnegie-Mellon University.

Dr. Hertzberg is the primary author of both the EPA’s 1986 Mixtures Guidelines, the first such guidelines by any federal agency, and the EPA's 2000 Supplementary Guidance for the Health Risk Assessment of Chemical Mixtures, and chaired both workgroups that developed those reports. He led the creation of MixTox, the EPA's database on binary toxicologic interactions, and co-developed with Patrick Durkin the EPA's interaction-based Hazard Index, which allows quantitative incorporation of toxic interaction information into a mixture risk assessment. He has co-developed and presented a mechanistically based model for a combination of two herbicides, showing significant interaction only at near lethal exposure levels, and has evaluated the numerical properties of the interaction-based Hazard Index using data on trihalomethanes. For the past ten years, he has co-taught a workshop on risk assessment of chemical mixtures at both the Society for Risk Analysis and the Cincinnati Toxicology and Risk Assessment annual meetings. Dr. Hertzberg initiated the use of ordinal regression to describe toxic severity, an approach that spawned the EPA's CatReg software and its use for acute exposures to air toxics. He has worked on EPA’s Office of Pesticide Programs' Cumulative Risk Work Group, EPA's Risk Assessment Forum cumulative risk technical panel, and external advisory groups on mixture risk for ATSDR, NIOSH and the Dutch Health Council. While at EPA he received two silver and two bronze medals and several awards for his advances and leadership in chemical mixtures risk assessment. He is a member of the Society for Risk Analysis, and the American Statistical Association, and is a recipient of the distinguished achievement medal from the ASA section on Statistics and the Environment.

read moreSteven Lewis, Ph.D., D.A.B.T., TERA Fellow


14 Merlin Drive
Washington, NJ 07882
908-689-8644 (voice & voice-mail)
stevencraiglewis@comcast.net (primary email)


President & Principal Scientist, Integrative Policy & Science, Inc.
Adjunct Professor, Robert Wood Johnson Medical School
Fellow, Toxicology Excellence for Risk Assessment (TERA)
Distinguished Scientific Associate, ExxonMobil Biomedical Sciences, Inc. (retired)
Senior Fellow, University of Texas at Dallas

Dr. Lewis holds a B.A. in Chemistry from Indiana University at Indianapolis (1970) and a Ph.D. in Toxicology (minor in Biomedical Sciences) from Indiana University School of Medicine (1975).

During the period of his graduate-school training and research, Dr. Lewis served as Analyst and Manager of the Indiana State Tumor Registry (the state-wide statistical cancer research unit).  After joining Exxon (now, ExxonMobil), he held various technical, consulting and management positions, including Head of the Petroleum & Synthetic Fuels Group.  For more than 28 years, Dr. Lewis served as a corporate advisor on scientific and science-policy issues in occupational and environmental health.  Dr. Lewis’ research and safety assessment activities have focused on assessing potential health risks from exposure to petroleum and chemical carcinogens, toxicants to the nervous system, and chemical hazards to reproductive health. On special assignment, Dr. Lewis served as the senior on-site health scientist (in Alaska) following the oil spill event of 1989.  His assignments included managing the human scientific program to assess potential human health impacts of the oil spill and clean-up.  Dr. Lewis is a four-time winner of ExxonMobil’s most prestigious awards for excellence in the health and environmental sciences: Exceptional Achievement Award in 1993 and consecutive ExxonMobil Ambassador Awards in 2001, 2002 and 2003.


Following retirement from ExxonMobil Biomedical Sciences, Inc. (December, 2003), Dr. Lewis founded an independent consulting service, Integrative Policy & Science, Inc. (IPSi).  The mission of IPSi is to provide public and private sector clients with advice in the specific areas of Dr. Lewis’ expertise, including general toxicology, qualitative and quantitative assessment of risk from occupational and/or environmental hazards, science policy (i.e., the interplay of the biomedical and environmental sciences with environmental health policy-making), and legislative/regulatory affairs.  Dr. Lewis has extensive experience in facilitating public engagement in environmental issues and decision-making, as well as in the area of risk communication.

In the role of Adjunct Professor, Department of Environmental and Occupational Medicine, Robert Wood Johnson Medical School (University of Medicine and Dentistry of New Jersey), Dr Lewis collaborates in undergraduate and post-graduate teaching.  Dr. Lewis is also a regular lecturer in the Science and Engineering Departments of Raritan Valley Community College (of New Jersey).

Dr. Lewis is a Diplomate of the American Board of Toxicology (certified in 1980, recertified in 1985, 1990, 1995, 2000, 2005).  He has served on the editorial boards of 4 scientific journals and is currently Associate Editor of Dose-Response (formerly, Nonlinearity in Biology, Toxicology and Medicine).  Dr. Lewis is very active in a variety of professional societies, including the Society for Risk Analysis (past-member of the governing Council and nominee for the office of President), the International Society for Regulatory Toxicology and Pharmacology (elected to governing Council in 2002; re-elected in 2006), and the Society of Toxicology.


Dr. Lewis has served as a Consultant to the U.S. EPA Science Advisory Board, and as a Member of the Risk Communication Subcommittee of the EPA Board of Scientific Counselors (of the Office of Research and Development).  He frequently provides comments on scientific and regulatory issues before U.S., state and international agencies and has repeatedly served as a selected peer reviewer for toxicological profiles, summaries and risk assessments.  He is a Past-Chair of the American Petroleum Institute’s Toxicology Committee, and a former member of the Board of Directors of the Toxicology Forum, past Chair of the American Industrial Health Council’s Science Policy Committee, and a former member of the Science Program Committee of the Chemical Industry Institute of Toxicology.  Dr. Lewis served as a member and Chairman of the Board of Trustees of TERA/ITER (a not-for-profit organization specializing in the assessment of health and environmental risks).  He is continuing his association with TERA in the role of collaborative Fellow. Dr. Lewis recently completed his term as a member of the U.S. National Research Council’s panel on "Public Participation in Environmental Decision-Making."


Dr. Lewis retains the title of Senior Fellow (Cecil and Ida Green Center for the Study of Science & Society, University of Texas at Dallas), where he was a Visiting Scholar in 1995.  Dr. Lewis has published and presented the results of his work widely, and has delivered numerous invited seminars and other presentations.


Charles Anthony Pittinger, Ph.D., TERA Fellow


6547 Edwood Avenue
Cincinnati, OH  USA  45224

Work: 513-218-9897
Alt: 513-729-4280



Dr. Pittinger is an environmental scientist with broad experience in ecotoxicology, environmental fate, and ecological risk assessments of organic chemicals, metals and mining products.  He provides leadership and success to multi-national corporations in meeting global product stewardship needs of their chemical products.  He has worked broadly in public (e.g., SETAC, the EPA’s Science Advisory Board) and private venues to provide technical insight and advancement in health and environmental fate and effects, regulatory compliance (e.g., GHS, REACH, HPV), technical external relations, and product sustainability (e.g., life-cycle analysis).


Dr. Pittinger has 27 years of experience in chemical safety and regulatory compliance, including 17 years with The Procter & Gamble Company and 10 years in environmental consulting with multiple industry sectors such as industrial and specialty chemicals, metals and mining, consumer goods, and pharmaceuticals.  Recently, he has also led projects for trade associations including the American Cleaning Institute, the International Council on Mining and Metals, and the Water Environment Research Foundation (WERF).  He brings technical, regulatory, and external relations experience to enable the freedom to market safe and sustainable products in highly dynamic global markets. 


As a Fellow, Dr. Pittinger and TERA have successfully leveraged their respective strengths in human health toxicology and industrial hygiene, and in ecotoxicology and environmental fate, to offer our project sponsors the full range of product stewardship services described below.  They assemble and manage multi-disciplinary staff at senior and junior levels to support project teams efficiently and cost-effectively, with excellent communications with clients.  Some examples include:


        For WERF, a TERA team compiled and analyzed complex chemical fate, health and environmental effects data for trace organic substances in biosolids and sludge-amended soils.


        For mining firms and local, provincial and national regulatory agencies, Dr. Pittinger chaired a peer review coordinated by TERA, of long-term soil amendment programs to restore lands near Sudbury Ontario impacted by historical mine smelting operations.


        For a private paint manufacturer, TERA developed and applied hazard prioritization scoring to product ingredients to evaluate substances of special concern and opportunities for product improvement in green chemistry.


        Dr. Pittinger and TERA have actively developed regulatory submissions including REACH dossiers and Chemical Safety Reports, CLP notifications, and High Production Volume Chemical Summaries and Test Plans.


        For a number of private firms preparing GHS-compliant Material Safety Data Sheets (GHS = Globally Harmonized System for Classification and Labeling of Chemicals), Dr. Pittinger has developed environmental hazard classifications and sound, weight-of-evidence justifications for organic and inorganic substances and mixtures.


        Dr. Pittinger has conducted chemical and product life-cycle sustainability evaluations, including verification of green certification criteria and product use consumption of water and energy.




Pamela R. D. Williams, Sc.D., TERA Fellow


4647 Carter Trail Boulder, Colorado 80301

phone: 303-284-1935



Dr. Williams' areas of expertise include retrospective exposure assessment, exposure modeling, health risk assessment, decision analysis, and risk communication.  Dr. Williams recently served as a Senior Science and Policy Advisor in the Office of Research and Development at the U.S. Environmental Protection Agency (EPA).  Her past projects include conducting scientific literature reviews and analyses of various chemicals (e.g., benzene, MTBE, asbestos), characterizing human exposures and health risks in occupational and community settings, designing and implementing indoor air exchange rate and exposure simulation studies, and designing environmental health education materials.  Most of this work has been published in the peer-reviewed literature and presented at technical and scientific conferences nationally and internationally.  


Dr. Williams is the 2007 recipient of the Joan M. Daisey Outstanding Young Scientist Award, granted in recognition of outstanding contribution to the science of human exposure analysis by a young scientist.  Dr. Williams received her MS in Health and Social Behavior and her ScD in Environmental Science and Risk Management from the Harvard School of Public Health.


Raymond York, Ph.D., DABT, ATS, ERT., TERA Fellow


(315) 692-4854



Dr. York is a board-certified toxicologist with almost 30 years of experience in the field of toxicology, specializing in reproductive and developmental toxicology.  He has served as a study director on over 700 GLP safety evaluation studies, and published over a 100 manuscripts, review articles, book chapters and abstracts, and has been an invited speaker at international conferences.  Dr. York earned his Ph.D. in Toxicology at the University of Cincinnati Medical Center, Kettering Laboratory and completed a two-year postdoctoral fellowship at the Children's Hospital Research Foundation in Cincinnati, in the area of developmental toxicology.


Dr. York has directed or participated in studies to evaluate safety exposure to chemicals from consumer products and pharmaceuticals to pesticides and water contaminates to assess compliance with USEPA (TSCA, FIFRA), FDA, ICH, and OECD requirements.  He has designed numerous acute, subchronic and chronic toxicology, teratology, and carcinogenicity studies in mice, rats, rabbits, dogs and primates.  Dr. York has planned, analyzed, interpreted and summarized toxicity data for the endocrine disruptor screening program (EDSP), multi-generational, development neurotox- and immunotoxicity studies, and is familiar with sperm morphology, vaginal cytology, fetal visceral and skeletal evaluation techniques.   


Dr. York has been a member of the Teratology Society since 1984, and has been a member and served as the President for both Midwest Teratology Association (MTA; 1989) and the Middle Atlantic Reproduction and Teratology Association (MARTA; 2004).  He has also been a member of the Society of Toxicology since 1985, and the American College of Toxicology since 1998.  As a member of the Reproductive and Developmental Toxicology Specialty Section of SOT, he served on its Nominating Committee in 2006 and currently the President for SOT's Mid-Atlantic Regional section (MASOT).  Dr. York has served as a reviewer for Toxicology and Applied Pharmacology and International Journal of Toxicology and as a member of the Editorial Board of Fundamental and Applied Toxicology.  He was the reproductive toxicologist reviewer for the USEPA Biodiesel Program and on the peer consultation panel for assessment of the potential risk of health effects from exposure to tertiary-butyl acetate (TBAC).