Past Assistant Secretaries for Environmental Management

William "Ike" White led the Department of Energy’s Office of Environmental Management (EM) from June 2019 until June 2024. He provided leadership for the safe cleanup of the environmental legacy brought about from five decades of nuclear weapons development and government-sponsored nuclear energy research.

Under his leadership, EM made major progress in liquid waste treatment systems, including beginning operations at the Salt Waste Processing Facility at the Savannah River Site, completing construction of the facilities supporting the Direct Feed Low-Activity Waste Treatment approach and beginning the first large-scale treatment of radioactive and chemical tank waste at the Tank-Side Cesium Removal System at Hanford. At Oak Ridge demolition was completed at the East Tennessee Technology Park, making it the first site in the world to remove an entire uranium enrichment complex. At the Portsmouth Site, demolition of X-326 uranium process building, a two-story structure covering 56 acres was a critical achievement in the cleanup and transformation of the Gaseous Diffusion Plant. He issued EM’s 10-year Strategic Vision outlining planned accomplishments over the next decade and the annual Priorities Scorecard summarizing achievements.

Before joining EM, he served as the Chief of Staff and Associate Principal Deputy Administrator for the National Nuclear Security Administration (NNSA) where he served as the primary point of contact within the Office of the Administrator for field office managers, providing leadership and coordination on operational and technical issues. Previously, White was the Deputy Associate Administrator for Safety and Health where he enabled the NNSA mission in the areas of nuclear and occupational safety, directly supporting the Administrator and senior managers throughout the NNSA enterprise. Earlier in his career, White served in a variety of leadership and technical positions in NNSA and at the Defense Nuclear Facilities Safety Board focused on nuclear safety and operations.

White has a Bachelor of Science in Electrical Engineering from the University of Mississippi and a Master of Science in engineering from the University of California, Berkeley.

Anne Marie White served as the ninth Senate confirmed Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management from March 2018 until June 2019.

Prior to joining EM she had more than 25 years of experience across a broad range of activities within the nuclear field with industry-recognized credentials in characterization and disposition of radiologically contaminated sites; dose modeling and assessment; and data analysis and integration leading to technically underpinned and cost effective solutions. She started her own consulting firm to provide creative solutions in solving complex environmental challenges domestically and internationally with both private and public organizations. She has extensive hands-on in the field experience at many DOE sites and has supported a number of emerging nuclear power nations to develop legal and regulatory structures and national policies to deliver safe and effective solutions to develop nuclear expertise for peaceful purposes. Her international work has included producing draft national regulations for foreign governments in areas of nuclear safety, environmental protection and nuclear liability issues and is a recognized leader for innovative stakeholder outreach strategies in diverse and difficult regulatory structures.

White holds a Bachelor of Science in Mathematics from the University of Kansas and a Master of Science in Nuclear Engineering/Health Physics from the University of Missouri-Columbia.

James Owendoff served as the Acting Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management (EM) from January 1998 until July 1999 and again from June 2017 until March 2018.

Owendoff served in various other capacities in EM including: Principal Deputy Assistant Secretary; Chief Operations Officer; Deputy Assistant Secretary for Environmental Restoration; Deputy Assistant Secretary for Science and Technology; Chief Office of Project Recovery; and Senior Advisor. Owendoff also served in DOE’s Office of Civilian Radioactive Waste Management from November 2003 to November 2005 as the Associate Director for Integration.

Prior to joining the Department and his retirement from active duty in the US Air Force, Owendoff served in the Office of the Deputy Under Secretary of Defense for Environmental Security and served as Chief of the Air Force Environmental Restoration Division.

Owendoff was commissioned in the US Air Force as a 2nd Lieutenant in June 1968. He held a series of successively responsible leadership positions during his 25-year career in the US Air Force, which included assignments throughout the United States and overseas.

He graduated from Virginia Polytechnic Institute in 1968 where he earned a Bachelor’s of Science in Mechanical Engineering. He also holds a Master’s of Engineering in Mechanical Engineering from Cornell University.

Susan Cange served as Acting Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management from January until June 2017.

Prior to becoming the Acting Assistant Secretary, Cange served 29 years in federal service in various leadership positions within the federal government including at the Department's offices of Environmental Management and Nuclear Energy and Assets Utilization. In addition, she was one of the founding members of the Reindustrialization Program in Oak Ridge, which transfers underutilized assets to the private sector to accelerate cleanup and promote economic development.

She was the manager for the Department’s Oak Ridge Office of Environmental Management where she was responsible for safely executing the environmental cleanup of the Oak Ridge Reservation. This entailed successfully managing the cleanup of the East Tennessee Technology Park, the Oak Ridge National Laboratory, and the Y-12 National Security Complex.

Cange holds a bachelor’s and a master’s degree in environmental engineering from Vanderbilt University.

Monica Regalbuto served as the eighth Senate confirmed Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management from August 2015 until January 2017.

Previously, she served as the Deputy Assistant Secretary of Fuel Cycle Technologies in the Department’s Office of Nuclear Energy, overseeing the development of our nation’s nuclear fuel cycle. From 2008 to 2011, Regalbuto worked as Senior Program Manager with EM’s Office of Waste Processing. In 1988, she joined Argonne National Laboratory where she worked on the development of high level waste treatment technology. She joined the BP-AMOCO team in 1996 to manage many of their projects and budgets. She returned to Argonne in 2001 as the head of the Process Chemistry and Engineering Department in the Laboratory’s Chemical Sciences and Engineering Division.

Regalbuto received her bachelor’s degree in chemical engineering from the Mexican Instituto Tecnológico y de Estudios Superiores de Monterrey and a Masters and Doctorate in Chemical Engineering from the University of Notre Dame.

Between May 2014 and October 2016, Mark Whitney served as the Principal Deputy Assistant Secretary and Acting Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management (EM).

Whitney served as a member of the US Government’s Senior Executive Service from 2005 until July 2012.  From July 2011 until May 2014, he served as the acting Principal Assistant Deputy Administrator for Defense Nuclear Nonproliferation at the National Nuclear Security Administration (NNSA). In this capacity, he was responsible to the Deputy Administrator for overseeing the day-to-day operations of a $2.3 billion nuclear security and nonproliferation program that includes global nuclear security, disarmament, fissile material disposition, and nonproliferation research and development efforts. Prior to that, Whitney served as Assistant Deputy Administrator for Nonproliferation and International Security, where he was responsible for DOE’s international programs on nuclear safeguards, nuclear controls, nuclear verification/transparency, and the NNSA nonproliferation and arms control policy. He also served as the acting ADA for Fissile Material Disposition where he was responsible for the Department’s highly enriched uranium down-blending and plutonium disposition efforts, including the Mixed Oxide Fuel Fabrication Facility construction project at the Savannah River Site.

He has also served as the Executive Director of the DOE Moscow Office, where he led the Department’s in-country activities on nuclear security, nonproliferation, and energy security, including power plant construction projects in Zheleznogorsk and Seversk that provided replacement heat and electricity capacity to enable the shutdown of the final Russian plutonium production reactors. In addition, Whitney also held positions as President, Global Strategies Consulting; Senior International Program Manager, Science Applications International Corporation (SAIC); and Director of Russian Programs, Institute for International Cooperative Environmental Research – Florida State University (FSU).

Whitney holds a Bachelor of Arts and a Master of Business Administration in Finance & Investments from George Washington University and is a graduate of the DOE’s Nuclear Executive Leadership Training Program.

David G. Huizenga served as the Acting Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management (EM) from July 2011 until February 2012 and then as Senior Advisor for EM from February 2012 to May 2018.

Huizenga has over 25 years of leadership, management, and technical experience in a wide variety of programs across the Department of Energy. He began his career researching and solving some of the Environmental Management program’s greatest challenges as a Pacific Northwest National Laboratory research engineer at the Hanford site in 1985. In that capacity, Huizenga worked on long-term solutions to aging single-shell tanks that were leaking radioactive waste in the soil and other activities to protect the Columbia River and developed computer-modeling tools to evaluate the long-term performance of low-level radioactive waste forms.

Huizenga served in EM for over a decade, beginning as a technical advisor on waste management policy and ultimately served as a Deputy Assistant Secretary. He was instrumental in establishing complex-wide waste management and nuclear materials disposition strategies that were used to accelerate closure of the Rocky Flats Plant and the removal of special nuclear materials from Hanford and other sites. He worked closely with the Carlsbad Field Office to open the Waste Isolation Pilot Plant, the world’s first deep geologic repository.

In 2002, Huizenga transferred to the National Nuclear Security Administration, where he has managed several key national security programs aimed at reducing the worldwide threat of nuclear terrorism by working cooperatively with over 100 countries to secure nuclear weapons and weapons-usable nuclear materials and enhance the detection of illicit trafficking of nuclear and other radioactive materials. From February to November 2002, he served as the Deputy Director of the Office of International Nuclear Safety and Cooperation. He then went on to serve as the Assistant Deputy Administrator for the Office of International Material Protection and Cooperation. Huizenga became the Principal Assistant Deputy Administrator for the $2.5 billion Office of Defense Nuclear Nonproliferation in January 2011.

He has a Bachelor of Science in Chemistry and a master’s degree in chemical engineering from Montana State University. He graduated as Outstanding Senior Chemist, Sigma Xi, 1980, and Outstanding Analytical Chemist, American Chemical Society, 1980. He has received Meritorious Presidential Rank Awards in 2000 and 2008 and the Secretary of Energy Gold Award in 1998.

Inés Triay served as the Acting Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management (EM) from November 2008 until May 2009 when she was Senate confirmed as the seventh EM Assistant Secretary, serving until July 2011. Prior to her appointment, she served as EM’s Principal Deputy Assistant Secretary, Chief Operations Officer and Deputy Chief Operations Officer. During her tenure in these positions, the program completed the cleanup of the Department’s Rocky Flats site in Colorado and the Fernald site in Ohio. She also played an instrumental role in the commencement of remote-handled transuranic waste disposal operations at the Department’s Waste Isolation Pilot Plant in New Mexico.

Prior to her executive positions in Washington, DC, she served as Manager of the Department’s Carlsbad Field Office. During her tenure, the number of transuranic waste shipments to the Waste Isolation Pilot Plant increased from one or two per week to 25 per week. She also spearheaded a national effort to significantly accelerate cleanup of transuranic waste sites, culminating in a plan that completes the disposal of all legacy transuranic waste 20 years early. Before managing the Carlsbad Field Office, she held several key positions at Los Alamos National Laboratory.

Triay received her bachelor’s degree in chemistry, magna cum laude, and her doctorate degree in physical chemistry from the University of Miami in Florida. 

James Rispoli served as the sixth Senate confirmed Assistant Secretary for the Department of Energy (DOE) Office of Environmental Management from August 2005 until November 2008. In 1999, he joined the Department of Energy from the private sector, where he had been Managing Principal for an ENR top-ranked engineering firm’s Hawaii-Pacific Region, and with a different ENR top-ranked firm, as president of a wholly-owned subsidiary known as M&E Pacific. He served as the Director, Office of Engineering and Construction Management from late 2001 until his appointment as Assistant Secretary in 2005.

Rispoli served in the uniform of our nation for 31 years, retiring as a Captain, Civil Engineer Corps, in the US Navy. During his career, he led major organizations in the fields of facilities engineering and construction management, including serving as the Public Works and Environmental Director for the Pearl Harbor Naval Complex, which included a nuclear shipyard. Prior to that, he was the top environmental official in the Naval Facilities Engineering Command and their global environmental programs.

He earned a Bachelor of Engineering in Civil Engineering from Manhattan College, a Master of Science in Civil Engineering from the University of New Hampshire, and a master’s degree in business from Central Michigan University.