Board of Directors

Mr. Shelton, a director since July 2006, has also held the position of Chairman of the Board of the Company since December 2014. Mr. Shelton served as the Chief Financial Officer (“CFO”) of S K Hart Management, LLC, a private investment management company (“S K Hart Management”), from 1999 until August 2018. Mr. Shelton served as President of Pony Express Land Development, Inc. (an affiliate of SK Hart Management), a privately held land development company, from January 2013 until August 2017, and has served on its board since December 2005. Mr. Shelton served as Director and CFO of S K Hart Ranches (PTY) Ltd, a private South African Company involved in agriculture, from March 2012 to March 2020. Mr. Shelton has over 20 years of experience as an executive financial officer for several waste management companies, including as CFO of Envirocare of Utah, Inc. (now EnergySolutions, Inc. (1995–1999)), a privately held nuclear waste services company, and as CFO of USPCI, Inc. (1982–1987), then a NYSE- listed public company engaged in the hazardous waste business. Since July 1989, Mr. Shelton has served on the board of Subsurface Technologies, Inc., a privately held company specializing in providing environmentally sound innovative solutions for water well rehabilitation and development. Mr. Shelton has a B.A. in accounting from the University of Oklahoma.

Mr. Bostick, a director since August 2020, is currently the CEO of Bostick Global Strategies, LLC, a position he has held since July 2016. Bostick Global Strategies, LLC provides strategic advisory support in the areas of engineering, environmental sustainability, human resources, biotechnology, education, executive coaching, and Agile Project Management. In February 2021, Mr. Bostick was selected by U. S. Senator Jack Reed, Chairman of the Senate Armed Services Committee, to serve as a member of the Naming Commission consisting of eight appointed individuals, tasked with renaming Confederate-named military bases and property. In 2023, the Secretary of the Army and the Chief of Staff of the Army requested Mr. Bostick’s assistance in transforming U.S. Army Recruiting Command (USAREC). Mr. Bostick worked with the U.S. Army to develop a plan which USAREC is now executing. Mr. Bostick previously served (from November 2017 to February 2020) as the COO and President of Intrexon Bioengineering, a division of Intrexon Corporation (formerly Nasdaq: XON; now Nasdaq: PGEN). Intrexon Bioengineering addresses global challenges across food, agriculture, environmental, energy, and industrial fields by advancing biologically engineered solutions to improve sustainability and efficiency. Since October 2020, Mr. Bostick has served as a board member of CSX Corporation (Nasdaq: CSX), a publicly-held rail transportation company, and since December 2020, as a member of both the Finance Committee and the Governance Committee of CSX Corporation. Since June 2021, Mr. Bostick has served on the Board of Trustees of Fidelity Equity and High Income Funds overseeing equity funds and high yield funds sponsored by Fidelity Investments, Inc., a privately-owned investment management company. Mr. Bostick continues to serve as a board member for several other privately-held and nonprofit organizations. Mr. Bostick was named as one of 2021’s Most Influential Black Corporate Directors by Savoy Magazine, a national publication that showcases and drives positive dialogue about Black culture. In 2024, the Association of Graduates selected Mr. Bostick as a Distinguished Graduate of the U.S. Military Academy at West Point.

LTG (ret.) Bostick has had a distinguished career in the U.S. military, retiring from the U.S. Army in July 2016 with the rank of Lieutenant General. Prior to his retirement, LTG (ret.) Bostick held a variety of positions within the U.S. Army, including the 53^rd Chief of Engineers and Commanding General, U.S. Army Corps of Engineers (2012-2016) and Deputy Chief of Staff and Director of Human Resources, U.S. Army (2009-2012). LTG (ret.) Bostick has been awarded many military honors and decorations during his military career, including the Distinguished Service Medal, the Defense Superior Service Medal, and the Bronze Star Medal.

As a White House Fellow, one of America’s most prestigious programs for leadership and public service, Mr. Bostick was a special assistant to the Secretary of Veterans Affairs.

Mr. Bostick graduated with a Bachelor of Science degree from the U.S. Military Academy at West Point and later returned to the Academy to serve as an Associate Professor of Mechanical Engineering. He holds Master’s degree in both Civil Engineering and Mechanical Engineering from Stanford University, an MBA from Oxford University, and a Doctorate in Systems Engineering from George Washington University.He is a Member of the National Academy of Engineering and the National Academy of Construction.

Dr. Centofanti, the founder of the Company and a director of the Company since its inception in 1991, has held the position of EVP of Strategic Initiatives since September 2017. From March 1996 to September 8, 2017 and from February 1991 to September 1995, Dr. Centofanti held the position of President and CEO of the Company. Dr. Centofanti served as Chairman of the Board from the Company’s inception in February 1991 until December 16, 2014. In January 2015, Dr. Centofanti was appointed by the U.S Secretary of Commerce Penny Prizker to serve on the U.S. Department of Commerce’s Civil Nuclear Trade Advisory Committee (“CINTAC”). The CINTAC is composed of industry representatives from the civil nuclear industry and meets periodically throughout the year to discuss the critical trade issues facing the U.S. civil nuclear sector. From 1985 until joining the Company, Dr. Centofanti served as Senior Vice President (“SVP”) of USPCI, Inc., a large publicly-held hazardous waste management company, where he was responsible for managing the treatment, reclamation and technical groups within USPCI. In 1981, he and Mark Zwecker, a current Board member of the Company, founded PPM, Inc. (later sold to USPCI), a hazardous waste management company specializing in treating PCB-contaminated oil. From 1978 to 1981, Dr. Centofanti served as Regional Administrator of the U.S. Department of Energy (“DOE”) for the southeastern region of the United States. Dr. Centofanti has a Ph.D. and a M.S. in Chemistry from the University of Michigan, and a B.S. in Chemistry from Youngstown State University.

Mr. Duff has held the position of President and CEO of the Company since September 2017 and a Board member since April 2023. Since joining the Company in 2016, Mr. Duff has developed and implemented strategies to meet growth objectives in both the Treatment and Services Segments. In the Treatment Segment, he continues to upgrade each facility to increase efficiency, and modernize and broaden treatment capabilities to meet the changing markets associated with the waste management industry. This growth includes expansion into international markets and additional market sectors, including development of new clients in the commercial power and oil and gas industries. In the Services Segment, which encompasses all field operations, he has completed the revitalization of business development programs, which has resulted in increased competitive procurement effectiveness, and broadened the market penetration within both the commercial and government sectors. Within the Services Segment, Mr. Duff has established a team of professionals with experience in conducting safe and efficient field operations while addressing complex technical challenges associated with removal of radioactive and hazardous waste contamination. Mr. Duff has over 40 years of management and technical experience in the DOE and the DOD environmental and construction markets as, variously, a corporate officer, senior project manager, co-founder of a consulting firm, and federal employee. Mr. Duff has an MBA from the University of Phoenix and received his B.S. from the University of Alabama.

Ms. Duggan, a director of the Company since May 2021, is the founder of Energy Security Partners, a global strategic advisory firm that helps clients navigate complex challenges in energy, security, and economic development.

An alumna of the Obama-Biden Administration, Ms. Duggan played a key role in shaping national policy as energy and environmental advisor to then-Vice President Joe Biden and Deputy Director of President Obama’s Detroit Task Force. She later served on the Biden-Harris Transition Team and was appointed to the Secretary of Energy Advisory Board (“SEAB”) under Secretary Jennifer Granholm. Previously, at the U.S. Department of Energy (DOE), she held senior leadership roles, including Liaison to the City of Detroit under Secretary Ernie Moniz, Director of Legislative, Regulatory, and Urban Affairs, and Stakeholder Engagement Director for the Office of Energy Efficiency & Renewable Energy (“EERE”).

Beyond government, Ms. Duggan was a Partner with the Honorable Thomas J. Ridge’s firm, RIDGE-LANE Limited Partners, and served on the external advisory board of the University of Michigan’s Erb Institute for Global Sustainable Enterprise and was a Board Member at the Global Council for Science and the Environment. In 2018, Ms. Duggan was named to the prestigious “40 Under 40” list by Crain’s Detroit Business and their inaugural “Notable Leaders in Sustainability” lists. She was named as the Founding Director of the University of Michigan’s School for Environmental and Sustainability (“SEAS”) Clinic in Detroit.

Currently, she sits on the corporate board of directors at Envergia, a privately-held industry leading global solution company for recycling Lithium-ion battery materials and BlueGreen Water Technologies, a privately-held company leading the charge in helping preserve and promote health and safety of water bodies worldwide. She also serves as corporate advisory boards for a number of privately-held companies that addresses environmental, energy and climate challenges which includes Our Next Energy, Inc. (ONE), Aclima, Inc., BlueConduit, Commonweal Ventures and Arctaris Impact Investors, among others.

Ms. Duggan attended the University of Vermont, where she completed her Bachelor of Science degree in environmental studies. Ms. Duggan also has a Master of Science degree in natural resource policy & behavior from the University of Michigan.

Ms. Duggan’s career in both the government and private sectors brings valuable experience and insight into solving complex issues. Her extensive knowledge and problem-solving experiences led the Board to conclude that she should serve as a director.

Mr. Grumski, a director of the Company since February 2020, has served since April 2020 as the President and CEO of TAS Energy Inc. (“TAS”), a wholly-owned subsidiary of Comfort Systems USA, Inc. (NYSE: FIX), a publicly-held company that provides mechanical and electrical contracting services in locations throughout the United States. Prior to the acquisition of TAS by Comfort Systems USA, Inc., Mr. Grumski served as President and CEO and a board member of TAS from May 2013 to March 2020. From 1997 to February 2013, Mr. Grumski was employed with Science Applications International Corporation (“SAIC”) (NYSE: SAIC), a publicly-held company that provides government services and information technology support. During his employment with SAIC, Mr. Grumski held various senior management positions, including the positions of President of SAIC’s Energy, Environment & Infrastructure (“E2I”) commercial subsidiary and General Manager of the E2I Business Unit. Mr. Grumski’s many accomplishments with SAIC included growing SAIC’s $300 million federal environmental business to a top ranked, $1.1 billion business; receiving the National Safety Council “Industry Leader” award in 2009; and receiving highest senior executive performance rating three years in a row. Mr. Grumski began his career with Gulf Oil Company and has progressed through senior level engineering, operations management, and program management positions with various companies, including Westinghouse Electric Corporation and Lockheed Martin, Inc. Mr. Grumski received a B.S. in Mechanical Engineering from The University of Pittsburgh and a M.S in Mechanical Engineering from West Virginia University.

Mr. Reeder, a director since 2003, is a principal shareholder of the law firm of Greenberg Traurig LLP, one of the nation's largest law firms, with 45 offices and 2,600 attorneys worldwide. Mr. Reeder served as Shareholder-in-Charge of the law firm’s Mid-Atlantic Region offices for ten years. His clientele includes celebrities, heads of state, sovereign nations, international corporations, and law firms. As the U.S. Army’s 14th Undersecretary (1993-97), he also served three years as Chairman of the Panama Canal Commission's Board, overseeing a multibillion-dollar infrastructure program. For the past 20 years, he has served on the Canal’s International Advisory Board.  He has written extensively in leading journals on corporate cybersecurity, served on the boards of the USO, the National Defense Industry Association (“NDIA”), chairing NDIA’s Ethics Committee, the Armed Services YMCA, the Marshall Legacy Institute, and many other private companies and charitable organizations. Mr. Reeder served as a director of ELBIT Systems of America, LLC, (2005-2020), a subsidiary of Elbit Systems Ltd. (NASDAQ: ESLT), a multi-billion-dollar provider of defense, homeland security, and commercial aviation system solutions. Mr. Reeder has served as director of WashingtonFirst Bank, the bank subsidiary of WashingtonFirst Bankshares, Inc. (NASDAQ: WSBI), from 2004 to 2017; Sandy Spring Bancorp, Inc. (NASDAQ: SASR), from 2018 to 2020; and Trustar Bank, a Virginia state-chartered bank (2022 - present). 

After successive 4-year appointments by Virginia Governors Mark Warner and Tim Kaine, Mr. Reeder served seven years as Chairman of two Commonwealth of Virginia military boards, and 10 years on the USO Board of Governors. Appointed by former Governor Terry McAuliffe to the Virginia Military Institute’s Board of Visitors (2014), he was reappointed in 2018 by former Virginia Governor Ralph Northam. Mr. Reeder, who has been a television commentator on legal and national security issues, is consistently named a Super Lawyer for Washington, D.C. In May 2018 he was appointed to the Advisory Council Bid Protest Committee to the United States Court of Federal Claims. 

A West Point graduate who served in the 82nd Airborne Division after Ranger School, Mr. Reeder earned his J.D. from the University of Texas, and L.L.M. from Georgetown University.  

Mr. Wamp, a director since January 2018, is currently the President of Zach Wamp Consulting, a position he has held since 2011. As the President and owner of Zach Wamp Consulting, he has served some of the most prominent companies from Silicon Valley to Wall Street as a business development consultant and advisor. From September 2013 to November 2017, Mr. Wamp chaired the Board of Directors for Chicago Bridge and Iron Federal Services, LLC (a subsidiary of Chicago Bridge & Iron Company, NYSE: CBI, which provides critical services primarily to the U.S. government). From January 1995 to January 2011, Mr. Wamp served as a member of the U.S. House of Representatives from Tennessee’s 3rd Congressional District. Among his many accomplishments, which included various leadership roles in the advancement of education and science, Mr. Wamp was instrumental in the formation and success of the Tennessee Valley Technology Corridor, which created thousands of jobs for Tennesseans in the areas of high-tech research, development, and manufacturing. During his career in the political arena, Mr. Wamp served on several prominent subcommittees during his 14 years on the House Appropriations Committee, including serving as a “ranking member” of the Subcommittee on Military Construction and Veterans Affairs and Related Agencies. Mr. Wamp has been a regular panelist on numerous media outlets and has been featured in a number of national publications effectively articulating sound social and economic policy. Mr. Wamp’s business career has also included work in the real estate sector for a number of years as a licensed industrial-commercial real estate broker, for which he was named Chattanooga’s Small Business Person of the Year.

Mr. Zwecker, a director since the Company's inception in January 1991, previously served as the CFO and a board member for JCI US Inc. from 2013 to 2019. JCI US Inc. is a telecommunications company and wholly-owned subsidiary of Japan Communications, Inc. (Tokyo Stock Exchange (Securities Code: 9424)), which provides cellular service for M2M (machine to machine) applications. From 2006 to 2013, Mr. Zwecker served as Director of Finance for Communications Security and Compliance Technologies, Inc., a wholly-owned subsidiary of JCI US Inc. that develops security software products for the mobile workforce. Mr. Zwecker has held various other senior management positions, including President of ACI Technology, LLC, a privately-held IT services provider, and Vice President of Finance and Administration for American Combustion, Inc., a privately-held combustion technology solutions provider. In 1981, with Dr. Centofanti, Mr. Zwecker co-founded a start-up, PPM, Inc., a hazardous waste management company. He remained with PPM, Inc. until its acquisition in 1985 by USPCI. Mr. Zwecker has a B.S. in Industrial and Systems Engineering from the Georgia Institute of Technology and an M.B.A. from Harvard University.