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Meet the EPCN Professionals

If you would like to meet one of EPCN’s environmental professionals, or learn more about the Environmental Professional Career Network,please email the EPA’s GMU representative Piyachat Terrell, at Please use the subject line “EPCN” in your email.


Colonel (Ret) Reginald E. Allen

Colonel (Retired) Reginald E. Allen is a member of the United States Government Senior Executive Service (SES) and is the Assistant Deputy Chief of Staff for the US Environmental Protection Agency HQ in Wash, DC. He is currently on a one year detail as an Executive-in-Residence, Affiliate Professor at George Mason University.

Prior to his SES selection in 2015 he served 30 years as an active duty combat arms officer in the United States Army. His last assignments include Chief of Staff/XO to the Under Secretary/Chief Management Officer of the Army in the Pentagon and later as Special Assistant to the Director, Joint Improvised Explosive Device (IED) Defeat Organization.

COL (R) Allen was born in New York City and was commissioned a second lieutenant of Armor and Cavalry in 1985.  He served in numerous command, staff and leadership assignments around the world.  In June 2003, COL (R) Allen assumed command of 1st Squadron, 10th United States Cavalry “Buffalo Soldiers” on the Iran-Iraq Border. The Buffalo Soldiers (4th ID (M) Division Cavalry Squadron) conducted a year of combat operations in Iraq. Task Force Saber consisted of three BN size units and over 2100 soldiers at the height of operations, the largest BN level combat formation in Iraq.  COL (R) Allen led the armor combat force in the operation that captured Saddam Hussein, secured the Iran-Iraq border, eastern Tikrit, and later Balad Joint Air Base then the largest concentration of US Soldiers in Iraq.  COL (R) Allen changed command in the summer 2005 and was assigned to Army Staff in the Pentagon where he served as a future operations planner and later as Military Assistant to the Secretary of the Army.

In 2008 COL (R) Allen was selected to be the Operation Officer for III Corps/Fort Hood. “America’s Armored Corps”.  In 2009, he assumed command of the 3d Armored Cavalry Regiment “Brave Rifles”. He deployed the Regiment in 2010 on its 4th combat deployment for Operation New Dawn in Iraq. The Regiment conducted a year of combat and training operations helping to set the conditions for an honorable US forces exit from Iraq. COL (R) Allen relinquished command in Nov 2011. In 2012, he became the Executive Officer to the Under Secretary of the Army for two years.

COL (R) Allen holds an MS in National Security Strategy from the National War College, National Defense University, a MA in Education from the University of Louisville and a BS in Business from NC A&T SU. COL (R) Allen is a graduate of the United Kingdom Higher Command Course.

COL (R) Allen’s highest military awards include: The Legion of Merit (x4), the Bronze Star (x3); Defense Meritorious Service Medal (2); and the Meritorious Service Medal (x7).

Col (Ret) Reginald E. Allen

Michael Flynn

Michael Flynn serves as the Acting Deputy Administrator of EPA. Previously, he was EPA’s Associate Deputy Administrator, serving as a key advisor to the Deputy Administrator on management and policy issues. He was the Director of the Office of Radiation and Indoor Air in OAR for six years, where he expanded federal action to address health risks from radon exposure indoors, enhanced EPA’s preparedness for radiation emergencies and played a role in the Agency’s response to the 2011 Japanese nuclear incident. Michael Flynn’s 38-year career at the Environmental Protection Agency has been one marked by sustained extraordinary accomplishments culminating as the Acting Deputy Administrator of the agency for the last 15 months. His steady, mature leadership of EPA in his current role came during arguably one of the most challenging Presidential transitions in the agency’s 48-year history. Prior to assuming his current role, he served as the Associate Deputy Administrator for eight months serving as the principal advisor to the Deputy Administrator on key agency regulatory, policy, and management issues. Michael Flynn came to EPA’s Office of the Administrator from the agency’s Office of Air and Radiation where from 2010 to 2016 he served as the Director of the Office of Radiation and Indoor Air.  Directing a staff of 160, he was responsible for overseeing national programs to protect public health and the environment from radiation and indoor air pollution.  For four months in 2011, he served as Acting Deputy Assistant Administrator of the Office of Air and Radiation, overseeing the office’s management issues, budget, and international programs.  From 2009 – 2010, Mike served as Acting Deputy Assistant Administrator of the Office of Environmental Information, where he oversaw a staff of over 400 and directed the Agency’s information management programs.  From 2001 to 2009, Mike led the Office of Information Analysis and Access, first as Deputy Director and then as Director, overseeing Agency programs that provide access to environmental information, including EPA’s website, library network and Toxics Release Inventory.  Mike began his EPA career in 1980 as an environmental scientist in the Office of Solid Waste, where he developed regulations to ensure the safe disposal of solid and hazardous wastes.

Mike holds a BS in Entomology/Plant Pathology from the University of Delaware (1978), and a MS in Public Health from the University of North Carolina (1979).  He is the recipient of the Lee M. Thomas Excellence in Management Award, four Bronze Medals for Commendable Service, and numerous special act awards.

Michael Flynn

Nigel Simon

Nigel Simon is the Acting Principal Deputy Assistant Administrator (PDAA) for the Office of Land and Emergency Management (OLEM) at the U.S. Environmental Protection Agency (EPA). In this capacity, Nigel provides direct leadership and oversight over OLEM’s $1.3 billion annual budget and manages several offices responsible for managing the EPA’s emergency, hazardous and solid waste management programs. OLEM represents approximately 16% of the total agency budget and a quarter of the agency’s employees. Prior to being named acting PDAA for OLEM, Nigel served as Senior Information Official and Director of the Office of Program Management in OLEM. Nigel’s career with the U.S. Environmental Protection Agency (EPA) spans more than 15 years where he has served in a variety of leadership roles. Prior to his appointment to the Senior Executive Service in December 2012, he served as the Director of the Information and Management Division in the Office of Congressional and Intergovernmental Relations (OCIR) before going on to Capitol Hill as a fellow. Nigel completed two short‐term mission assignments in Botswana and Cameroon, West Africa as part of the United Nations Environmental Program and the EPA. He was an active member of the EPA Response Support Corps and was deployed to Mississippi as part of the Deepwater Horizon Oil Spill Cleanup. Before coming to EPA, Nigel was a military policeman in Maryland and the U.S. Virgin Islands Army National Guard units. He was deployed to Fort Clayton, Panama. He holds a Master of Public Administration degree from the University of Virgin Islands and a Bachelor of Arts degree from Central College in Iowa. Nigel and his spouse, Dr. Alvin B. Williams, live in Prince Georges County, Maryland and are the proud parents of three adopted children and a cocker spaniel named Rocky.

Nigel Simon

Mark Rupp

Mark Rupp serves as Director, Wildlife Campaign at the Environmental Defense Fund (EDF) where he coordinates activities in defense of the Endangered Species Act and support for expanding and enhancing habitat on America’s working lands.  Mark joined EDF after having served as Deputy Associate Administrator for Intergovernmental Relations at the U.S. Environmental Protection Agency (EPA) where he oversaw State and Local Relations, State Partnerships, and Regional Operations.  Prior to EPA, Mark served as:  Director, Washington, DC Office for former Governor Chris Gregoire (WA); Health and Human Services Policy Advisor to Governor Gregoire in Olympia, Washington; Legislative Counsel to U.S. Senator Maria Cantwell (WA) in Washington, DC; and held staff positions in the Washington State House of Representatives. Mark is an attorney with a Bachelor of Science degree in Environmental Policy and Assessment.

Mark Rupp

W. Michael McDavit

W. Michael McDavit is currently the Chief of the Program Development and Jurisdiction Branch in the Office of Water, USEPA. His unit administers technical and financial support for enhancing state and tribal wetland programs, and leads policy, program and science development issues related to “waters of the United States” under the Clean Water Act. He has been with EPA for 26 years. Mike holds a BS in Environmental Science from the University of Wisconsin at Green Bay and a MPA from The George Washington University. He is a Senior Fellow with the Excellence in Government program and an officer in the American Society for Public Administration’s Section on Environmental and Natural Resources Administration. His nearly 40-year career in and out of government has spanned a variety of environmental disciplines, including regulation of pesticides, management of hazardous waste, and air and water pollution control. He has licensed “biopesticides,” including biotech products, and managed programs advancing integrated pest management, environmental stewardship and sustainability. During his time at EPA, Mike has also developed Agency-wide policy in the Office of Policy, and served as a Special Assistant in the Office of the Administrator. In Europe, Mike directed a Department of Defense unit responsible for hazwaste management and disposal in more than 15 countries. During his nine years abroad, he helped close U.S. military bases after the fall of the Berlin Wall and set up the first permanent hazmat operations in the Middle East. Some of his fondest memories of his career, however, involve slogging through Lake Michigan’s Green Bay marshes as an undergrad Sea Grant research assistant in the 1970’s. A native Washingtonian, Mike is married and has one grown son.

W. Michael McDavit

Donna Downing

Donna Downing is a policy analyst and attorney at the U.S. Environmental Protection Agency (EPA), and has served as Jurisdiction Team Leader in EPA’s Office of Water since 2005. Donna works on a variety of issues, with a focus in recent years on which waters are protected by the Clean Water Act (CWA) in light of the U.S. Supreme Court decisions. Donna has been with EPA since 1998. She previously worked for the U.S. Congress Office of Technology Assessment, and in private law practice. She has a BA from Harvard University graduating magna cum laude, a MPP from the University of California at Berkeley, a JD from Georgetown University cum laude, and a LLM in Environmental Law summa cum laude from George Washington University. Donna teaches environmental law as an adjunct professor at George Washington University Law School, and was awarded the Distinguished Adjunct Faculty Award in 2012. In what’s left of her time, Donna moonlights as a professional potter and an unprofessional horse trainer.

Donna Downing

Benita Best-Wong

Benita Best-Wong, Acting Deputy Assistant Administrator for the Office of Water at EPA. Benita Best-Wong has devoted 30 years of her career to fresh and marine water protection and restoration, and has managed the implementation of national efforts on watershed planning, water quality assessment and monitoring, source water and groundwater protection, and numerous other national programs and initiatives at EPA. She has also managed several regional initiatives, including efforts to protect the Great Lakes, Lake Champlain and Onondaga Lake, as well as promulgating Puerto Rico’s guidance for water-quality based permitting.

In December 2013 Benita was selected to head the Office of Wetlands, Oceans, and Watersheds (OWOW), in which role she has advised the Assistant Administrator for Water on a broad area of policy issues related to wetland, marine, watershed, and estuary protection. OWOW is a leader in national efforts to protect and restore freshwater, coastal, and marine ecosystems. OWOW accomplishes this goal by using sound science and implementing core Clean Water Act and other authorized programs in collaboration with other federal agencies, states, tribes, and other partners.

Benita was named Acting Deputy Assistant Administrator for Water in January 2017, in which role she is the lead across the Office of Water on budget and performance issues, as well as other operational matters. Benita will serve an indefinite term as Acting Deputy Assistant Administrator for Water before returning to OWOW as Director.

Specialties: Watershed planning, water quality assessment and monitoring, wastewater discharge permitting, municipal wastewater discharge, human and information technology capital management, budget formulation and execution, organizational development, green infrastructure, low impact development.

Benita Best-Wong

Ruth A. Etzel, M.D.

Dr. Ruth Etzel is the Director of the Office of Children’s Health Protection. Dr. Etzel is a pediatrician and specialist in preventive medicine and public health. She came to EPA in 2015. During her career, which spans over 30 years, she has worked at the tribal, national and international level to protect children from hazards in the environment. Dr. Etzel has a broad background in public health, with specific training and expertise in pediatrics, preventive medicine, and children’s environmental health. From 2009 to 2012 she served as the Senior Officer for Environmental Health Research in the Department of Public Health and Environment at the World Health Organization in Geneva, Switzerland. Previously, as a Commissioned Officer in the US Public Health Service, Dr. Etzel served in numerous public-sector leadership positions including: US CDC (Founding Chief of the Air Pollution and Respiratory Health Branch), US Department of Agriculture (Director of the Division of Epidemiology and Risk Assessment) and US Indian Health Service (Research Director at the Alaska Native Medical Center). Dr. Etzel was a member of the US National Institutes of Health’s First Expert Panel on the Management of Asthma and the US Department of Defense Science Board Task Force on Gulf War Heath Effects.

Dr. Etzel is the founding editor of Pediatric Environmental Health (a 3rd edition of the book was published by the American Academy of Pediatrics in 2011). This influential book has helped to train hundreds of doctors who care for children about how to recognize, diagnose, treat and prevent illness in children from hazards in the environment. For more than 20 years she has worked with international organizations to educate health professionals about environmental health and to build their capacity to conduct environmental investigations.

Dr. Etzel has received numerous awards, including:

The Distinguished Service Award from the U.S. Public Health Service, the Don C. Mackel Memorial Award from Centers for Disease Control and Prevention, the Arthur S. Flemming Award, and the Clinical Society Award from the U.S. Public Health Service Commissioned Officers Association.

Dr. Etzel received an M.D. from the University of Wisconsin and a Ph.D. in Epidemiology from the University of North Carolina School of Public Health in Chapel Hill, North Carolina.

She is the founding editor of the popular book Pediatric Environmental Health and the co-editor of the Textbook of Children’s Environmental Health.

Dr. Ruth A. Etzel, M.D., Ph.D.

Tom Brennan

Tom Brennan is the Acting Director of EPA’s Science Advisory Board Staff Office. Mr. Brennan has over twenty-five years of professional experience working in the fields of risk policy, risk assessment and environmental science. Mr. Brennan began his career working for consulting firms in the Washington, D.C. area. His consulting work supported risk assessment activities for U.S. Department of Agriculture, the Department of Defense, and EPA.

For the past nineteen plus years, he has been working for EPA, where he has held several positions including Risk Assessor, Communications Officer, Team Leader, and Branch Chief.  He has been the Deputy Director of the Science Advisory Board Staff Office and the Office of Environmental Education, and Chief of Staff for the Office of Public Engagement and Environmental Education. In addition to his work at EPA, Mr. Brennan was also an Adjunct Professor in the Biology Department of Montgomery College, where he taught Environmental Science and General Biology from 2011-2014. Mr. Brennan has also been a guest lecturer for the past 16 years at Duke University where he helps teach a course of Risk Assessment Principals at the Nicholas School for the Environment. Mr. Brennan has a B.S. and M.S. degree from Ohio University in Botany/Plant Biology.

Tom Brennan

Denise Benjamin Sirmons

Denise Benjamin Sirmons serves as the Director of the Office of Small and Disadvantaged Business Utilization, responsible for leading the EPA’s efforts to advance the business, regulatory and environmental compliance concerns of small and disadvantaged businesses.

Denise has served in various leadership positions at the EPA, including in the Office of Diversity, Advisory Committee Management and Outreach, Office of Grants and Debarment, and the Office of Acquisition Management. Before joining the EPA, Denise was the Assistant General Counsel for Contracting at the U.S. Small Business Administration, and worked as a litigator for a major national law firm.

Denise holds a Master of Laws Degree in Government Procurement Law, with Honors, from George Washington University Law School. She also earned a Juris Doctor, cum laude, from Howard University Law School, and a Bachelor of Arts Degree in Political Science from McGill University in Montreal, Canada. She is the recipient of several awards, including the Patricia A. Tobin Government Contracts Award. She has also published articles in the Public Contract Law Journal and the Howard Law Journal.

Denise Benjamin Simmons

Joel Scheraga

As the Senior Advisor for Climate Adaptation at the U.S. Environmental Protection Agency, I have led EPA’s efforts to help the federal government, states, tribes, and local communities prepare for and increase their resilience to the impacts of climate change. Working across agencies and disciplines, I have drawn on expertise in climate change science and policy, geophysics, environmental economics, and the integration of science and policy to help stakeholders build and strengthen their adaptive capacities. A central focus of my work has been to ensure that investments made with taxpayer dollars to protect public health and the environment will be effective even as the climate changes. Dr. Joel D. Sheraga has worked extensively on interdisciplinary environmental problems and has expertise in the areas of climate change science and policy, environmental economics, the integration of science and policy, and applied microeconomics.

He earned his Ph.D., Economics in 1981, M.A., Economics in 1979, and A.B, Geology – Mathematics/Physics in 1976 all from Brown University.

Joel Scheraga

Reggie Cheatham

Reggie Cheatham is the Director of the Office of Emergency Management (OEM) within the Office of Land & Emergency Management (OLEM), serving the U.S. Environmental Protection Agency (EPA).  Reggie has 30 years of federal service, 27 of which are with the EPA.

Prior to joining OEM, Reggie served as the Director of the Federal Facilities Restoration and Reuse Office (FFRRO) within the Office of Solid Waste and Emergency Response (OSWER), currently known as OLEM. Reggie has also served as the Director for both the Quality Staff and the Environmental Analysis Division in the Office of Information Analysis and Access in the Office of Environmental Information (OEI). He has also served in the Office of Enforcement and Compliance Assurance (OECA) as the Deputy Director for the Regional Support Division (Superfund Enforcement) Office of Site Remediation Enforcement and the Chief of the Chemical Industry Branch. His first positions with the EPA were as an Environmental Engineer for both the Federal Facilities Enforcement Office in OECA and the Resource Conservation and Recovery Act (RCRA) Enforcement Division in OSWER.

Prior to joining EPA, Reggie worked as a Civil Engineer and Project Manager in the construction industry and served in the United States Army.  He holds a Bachelor’s of Science in Civil Engineering and a Master’s of Science in Environmental Engineering, both from George Washington University.

Reggie Cheatham

I Mei Chan

I Mei Chan
Senior Workforce Development Advisor, Office of Air and Radiation, U.S. Environmental Protection Agency

For over 30 years, I Mei’s professional life spans the Federal Government, the nonprofit, and the private sectors. Early in her career, she spent 11 years as an Information Technology professional for companies including IBM, NCR and Unisys Corporation. Since joining the Environmental Protection Agency (EPA) in 1993, I Mei has been expanding her career horizons in different roles of increasing responsibilities and impact across five major offices in EPA:

  • Senior Workforce Development Advisor, Office of Air and Radiation
  • Acting Supervisor, Office of Research and Development
  • Human Capital Lead and Regulatory Development Coordinator, Office of Environmental Information
  • EPA’s Central Directives Officer, Office of Administration and Resources Management
  • Director of Special Projects, National Trust for Historic Preservation (on IPA from EPA)
  • Local Area Network Administrator, Office of Land and Emergency Management

In addition, I Mei is also an experienced and expert facilitator and internal coach for over 15 years. She currently holds the credentials of an Associate Certified Coach by the International Coach Federation (ICF), a Certified Strengths Coach by Gallup, and a Certified Leadership Coach by Georgetown University. Her coaching is also informed by many of her certification training, to include: Emotional Intelligence, Positive Psychology, Appreciative Inquiry and Conflict Coaching.


  • Master of Science Coursework in Traditional Chinese Medicine, American College of Traditional Chinese Medicine, San Francisco, CA; and Meridian Institute of Integrated Chinese Medicine, Monterey, CA — 1999-2001
  • Bachelor of Arts in Business Administration, Sacred Heart College, Belmont, NC —1984
I Mei Chan

Kevin Baily

Kevin Baily supervises an interdisciplinary staff providing technical and administrative direction in a number of operational areas. The portfolio of RMOD includes personnel, budget, congressional and gubernatorial correspondence, Freedom of Information Act responsibilities, and other functional areas supporting OCIR. Areas of Expertise include Strategic Planning, Budget, Personnel, and Process Improvement. Academic Background: Bachelor of Arts, History, North Carolina Central University; Master of Arts, European History, North Carolina Central University.

Kevin Baily