COL Hoffman grew up in York, Pennsylvania and was commissioned into the Chemical Corps from the Pennsylvania State University with a B.S. in Chemical Engineering.

His first assignment was to the 82d Airborne Division, Fort Bragg, NC; holding staff positions at Brigade and Battalion level and leading a platoon in the 21st Chemical Company (Airborne). Following the Chemical Advanced Course, he served as the Brigade Chemical Officer and as a Company Commander in the 17th Aviation Brigade in the Republic of Korea. Upon completion of command, he was assigned to Aberdeen Proving Ground, MD and served as the Aide-de-Camp to the Commanding General of the Soldier, Biological, and Chemical Command and as a Team Leader in the US Army Technical Escort Unit; leading a team in support of Operations Enduring Freedom and Iraqi Freedom. Upon redeployment, COL Hoffman served as the Chemical Branch Representative and as an Instructor at the United States Military Academy.

After completing his duties at West Point and graduating from the Command and General Staff College, he moved to Fort Hood, Texas and served as the Operations and Executive Officer of the 2d Chemical Battalion as well as the Operations Officer for the 48th Chemical Brigade. Upon leaving the 48th Chemical Brigade, COL Hoffman again supported Operation Enduring Freedom as an Afghan Security Forces Advisor with the 4th Brigade Combat Team from the 10th Mountain Division. After redeploying and serving a short period on the III Corps staff, he took command of the 2d Chemical Battalion.

Following command of the Red Dragons, he served on the Army Staff in the Pentagon working for the Deputy Chief of Staff for Programming, G-8, as the CBRN Branch Chief. Subsequent to his time on the Army Staff, COL Hoffman completed the Army War College and served as the Director for Operational Protection for the Eighth Army in Korea. Following his tour in Korea, COL Hoffman returned to Fort Hood and commanded the 48th Chemical Brigade. COL Hoffman is currently performing the duties of the Deputy Assistant Secretary of Defense for Chemical and Biological Defense.

COL Hoffman’s awards and decorations include the Legion of Merit, Bronze Star with oak leaf, Meritorious Service Medal with six oak leaf clusters, the Army Commendation Medal with three oak leaf clusters, and the Master Parachutist Badge. Additionally, he also holds a Masters of Public Administration degree from John Jay College of Criminal Justice and a Masters in Strategic Studies from the U.S. Army War College.

Ms. Cassandra (Cassie) Simmons-Brown is Performing the Duties of the Principal Director to the Deputy Assistant Secretary of Defense for Chemical and Biological Defense (DASD(CBD)). In this role, Ms. Simmons-Brown is responsible for efforts to integrate all phases of the planning, programming, budgeting, and execution processes that ensure alignment of investments against defined strategic goals, standardize business processes, utilize available business analytic tools, and adopt industry best practices, as appropriate, in the performance of budget oversight and resource management.

Ms. Simmons-Brown also continues her role as the Director, Resources and Business Operations. She leads enterprise-wide change for improving budget formulation and execution, provides insightful program analysis, and leverages information technology capabilities to support decision-making.

Ms. Simmons-Brown began her acquisition career as a defense contractor in 1991 before joining the federal workforce in 2004 at the Defense Threat Reduction Agency’s Joint Science and Technology Office for Chemical and Biological Defense. In 2010, she joined the material developer acquisition team at the Joint Program Executive Office for Chemical, Biological, Radiological, and Nuclear Defense. She led enterprise-wide financial management changes, audit readiness, budget formulation and execution, and implemented the enterprise resource planning (ERP) capabilities before attending Senior Service College in 2019.

Additionally, Ms. Simmons-Brown has Defense Acquisition Workforce Improvement Act (DAWIA) Level III Certifications in Business and Financial Management, Program Management, and DoD Financial Management. She is also a SAP Certified Associate - Business Process Integration and an American Society of Military Comptrollers (ASMC) Certified Defense Financial Manager – Acquisition (CDFM-A).

Ms. Simmons-Brown has a Bachelor of Arts degree in Political Science from Marymount University, a Master of Arts degree in Public Administration from Bowie State University, and a Master of Science in National Security and Resource Strategy/Minor in Senior Acquisition Course from National Defense University Eisenhower School.

Mr. Drew Walter is a career member of the Senior Executive Service and serves as the Deputy Assistant Secretary of Defense for Nuclear Matters. In this role, Mr. Walter is responsible for carrying out the Office of Nuclear Matters mission “to ensure the continued credibility, effectiveness, safety, and security of the U.S. deterrent in order to deter nuclear and non-nuclear attack; assure U.S. allies and partners; achieve U.S. objectives if deterrence fails; and hedge against an uncertain future.” Nuclear Matters is the Department of Defense (DoD) focal point for a wide range of issues related to the U.S. nuclear weapons stockpile, nuclear counterterrorism, and nuclear counterproliferation.

Before being assigned as DASD(NM), Mr. Walter served as Senior Advisor to the Deputy Under Secretary of Defense for Acquisition and Sustainment, The Honorable Alan Shaffer. In this role, Mr. Walter supported the Deputy Under Secretary’s efforts to integrate efforts across the Department related to nuclear deterrent modernization and sustainment

In 2018, Mr. Walter joined the Department as Principal Director and Senior Advisor in the Office of Nuclear Matters.

Prior to joining DoD, Mr. Walter served as a professional staff member with the Committee on Armed Services in the U.S. House of Representatives. In this role, he was responsible for executing committee activities and oversight regarding all policies, programs, and budgets related to nuclear deterrence, nuclear nonproliferation, naval nuclear propulsion, and nuclear environmental cleanup. This included oversight and authorization of over $30 billion in annual funding within the Department of Defense and the National Nuclear Security Administration.

Mr. Walter began his career at Sandia National Laboratories, where he was a Senior Member of the Technical Staff. His responsibilities at Sandia included conducting physical security assessments for U.S. nuclear weapons, developing and analyzing new security technologies and novel security assessment methodologies, and conducting special studies for laboratory executives.

Mr. Walter holds Bachelor's and Master's of Science degrees in Mechanical Engineering, both from the Rochester Institute of Technology.

Currently, Mr. Craig P. Campbell is performing the duties of the Deputy Assistant Secretary of Defense for Threat Reduction and Arms Control (DASD/TRAC), but maintains the portfolio of the Principal Deputy to the DASD/TRAC. He reports direct to the Assistant Secretary of Defense for the Nuclear, Chemical and Biological Defense Programs (ASD (NCB)) within the Office of the Secretary of Defense. In this capacity, he provides oversight of the Defense Threat Reduction Agency’s execution of the Cooperative Threat Reduction Program. He advises the DASD (TRAC) on formulation of policy, plans and is the DoD treaty manager for all chemical, biological, nuclear and conventional treaties and agreements, except for New START. He has oversight of Chemical and Biological Weapon elimination research and development and Countering Weapons of Mass Destruction System development. He also is responsible for the U.S. chemical demilitarization program and the Assembled Chemical Weapons Alternative program (ACWA) which is destroying the last remaining stockpile of U.S. chemical weapons. In his previous assignment, he was the Principal Deputy in the office of Nuclear Matters and was responsible for the oversight of programs to provide a safe, secure, and effective nuclear deterrent and the means to counter nuclear threats.

Mr. Campbell is retired from the United States Air Force. Prior to his retirement, he served as the Military Assistant to the ASD (NCB). He has over 3,000 hours as a Command Pilot with time in the T-37, T-38, F-16, KC-135A/D/G/L/R, and the B-1B. n

Mr. Campbell entered the Air Force in 1986 as a graduate of the U. S. Air Force Academy. He is married and has two sons.

Dr. Rhys M. Williams, a Tier 3 member of the career Senior Executive Service, is the Acting Director, Defense Threat Reduction Agency (DTRA). Dr. Williams leads the 2100 military and civilian members of the Agency, operating in over 50 countries, and executes over $2.4B to support US Nuclear Operations, Counter Proliferation, Nonproliferation, Arms Control, and Counter Network activities across the WMD and improvised device threat space. As a Combat Support and Defense Agency, DTRA provides the Combatant Commands and Services leading edge capabilities to execute their mission across the full continuum of gray zone and warfighting activities..

Prior to assuming his current position, Dr. Williams served as the Director for research, development, test, and evaluation activities for the Agency. He directed a geographically-dispersed military and civilian workforce of more than 450 Ph.D. level engineers and scientists and executed an annual budget of more than $1B. He led the Department of Defense’s primary science and technology (S&T) program to develop capabilities to detect, deter, and defeat foreign chemical, biological, radiological, and nuclear Weapons of Mass Destruction (WMD), as well as improvised threat devices. As one of the S&T Executives for DoD, Dr. Williams was the senior Agency S&T interface with the Military Services and the DoD, Office of the Undersecretary of Defense for Research and Engineering (USD(R&E)).

Dr. Williams previously served as the Assistant Deputy Administrator (Deputy Assistant Secretary – DAS position) for Defense Nuclear Nonproliferation R&D at the U.S. Department of Energy’s National Nuclear Security Administration (NNSA). In addition, he also served as Acting Principle Deputy Administrator (PDAS level) for Defense Nuclear NonProlfieration within NNSA.

Dr. Williams specializes in issues at the intersection of technology development and national security policy. He led policy, R&D, analytical, and operational organizations in both the public and private sectors with a specific focus on nonproliferation and counterproliferation activities.

Dr. Williams holds a Bachelor of Science in Engineering Physics from Miami University; a Master of Arts in International Science and Technology Policy from the Elliott School of International Affairs at George Washington University; and a Ph.D. in Public Policy, with an emphasis in science and technology policy in a national security context from the School of Public Policy, George Mason University. A former submarine officer, Dr. Williams was qualified as a nuclear power plant manager through the Naval Nuclear Propulsion Program and also served as a nuclear weapons officer. He is the author of a number of publications, including a National Intelligence Estimate. Dr. Williams is a level 3 acquisition professional and the recipient of a Presidential Rank Award.

Dr. Brandi C. Vann currently serves as the Acting Assistant Secretary of Defense for Nuclear, Chemical, and Biological Defense Programs (Acting ASD(NCB)). In this capacity, she is the principle advisor to the Secretary, Deputy Secretary and Under Secretary of Defense for Acquisition and Sustainment (A&S) on nuclear energy, nuclear weapons and chemical biological defense.

Prior to her acting role she was the Deputy Assistant Secretary of Defense for Chemical and Biological Defense Programs (DASD(CBD)) where she conducted Department-level research, development, and acquisition (RDA) activities from concept and requirements development, through early science and technology, to advanced development, testing and evaluation, and procurement. These efforts focus on reducing risk from emerging threats and fielding sustainable capabilities to all Services in accordance with Department, Service, and Combatant Command priorities for chemical, biological, and radiological (CBR) defense (CBRD) and ensure our warfighters can fight and win in chemical, biological, radiological, and nuclear (CBRN) contested environments.

Previously, Dr. Vann worked for the Defense Threat Reduction Agency (DTRA) where she served as the Chief of Advanced and Emerging Threats. At DTRA, she led the assessment of future chemical and biological (CB) combat threats to aid in the prioritization of capability investments to provide protection, situational awareness and recovery to the future force, as well as inform the creation of CB Doctrine and Concepts of Operations. During her tenure she also led the development of medical countermeasures, environmental detection and medical diagnostic systems. She has received numerous commendations for her work including the Office of the Director of National Intelligence Meritorious Achievement Award for her management of an innovative program to detect contaminated battlefields.

Prior to her joining the Department of Defense, Dr. Vann served as the Director of Laboratories for Nephron Pharmaceuticals Corporation (NPC). While there, she was responsible for the start-up of new state-of-the-art facility for the manufacturing of generic respiratory therapies and sterile pre-filled medications for hospitals and medical facilities. In this role, she was responsible for the build of laboratory infrastructure and the regulatory clearance to commence full operational capability.

Dr. Vann was a visiting scientist at the Counterterrorism and Forensic Science Research Unit at the Federal Bureau of Investigation (FBI). While at the FBI, Dr. Vann provided research expertise in forensic toxicology and trace analysis in support of the FBI Laboratory Division mission to include development of novel methodologies for chemical and biological agent analysis in environmental and clinical samples.

Dr. Vann also worked at the South Carolina Department of Agriculture Livestock Poultry Health as a Veterinary Forensic Toxicologist where she provided clinical and research expertise for the protection of the food supply system and health of state public and agricultural industry.

Dr. Vann received her PhD in Chemistry from the University of South Carolina where she studied analytical chemistry and applied statistics. She also held a Senior Executive Fellowship from the Kennedy School at Harvard University.

U.S. Army Major General Antonio M. Fletcher serves as the Deputy Director of the Defense Threat Reduction Agency (DTRA). Prior to coming to DTRA, he was Commander, Special Operations Command South, U.S. Special Operations Command.

General Fletcher graduated from the U.S. Military Academy (West Point) in 1989 and was commissioned in the U.S. Army as an Infantry Second Lieutenant. He began his Army career in the 197th Infantry Brigade at Fort Benning, Georgia, where he served as both a Rifle and Scout Platoon Leader, HHC XO, and Battalion Maintenance Officer. After graduating the Special Forces Qualification Course in 1996, General Fletcher was assigned to the 7th Special Forces Group (Airborne) where he served as a Company XO and Detachment Commander. From 1999-2002, he served as the Special Forces Assessment and Selection Company Commander, and graduated from the Command and General Staff College in 2002. General Fletcher returned to the 7th SFG(A) where he served as a Company Commander, Battalion Operations Officer, Group Operations Officer, and Deputy J3 for Combined Joint Special Operations Task Force-Afghanistan (CJSOTF-A).

In 2005, General Fletcher was assigned to the U.S. Army Special Forces Command (Airborne) and served as the G3. During this assignment he deployed as the J3 for CJSOTF-A. He then returned to the 7th Group to command 3rd Battalion, during which he deployed forces throughout USSOUTHCOM area of responsibility and Afghanistan. While in command, he served as Commander of Special Operations Task Force 73, comprised of Army, Air Force, Marines, and Afghan Special Operations Forces. Following command, General Fletcher served as the G3 of the U.S. Army Special Forces Command (Airborne). In 2011, he assumed command of 7th SFG(A). His command included a rotation as the CJSOTF-A commander. Following command, General Fletcher served as the Chief of Staff for the 82nd Airborne Division and the 1st Special Forces Command (Airborne) (Provisional), which included a tour as the Deputy Commander for the Special Operations Joint Task Force – Iraq (SOJTF-I). From 2016-2017, General Fletcher served as the Deputy Commander for Special Operations Joint Task Force - Afghanistan. From 2017-2018, he served as Director of Strategy, Policy, and Plans (J5) at USSOUTHCOM.

General Fletcher holds a Master’s Degree in Strategic Studies from the Marine Corps War College.