Assistant Secretary of Defense for Nuclear , Chemical & Biological Defense Programs The Assistant Secretary of Defense for Nuclear , Chemical & Biological Defense Programs , or ASD ( NCB ) , is the principal adviser to the Secretary of Defense , Deputy Secretary of Defense and the Under Secretary of Defense for Acquisition , Technology and Logistics for all matters concerning the formulation of policy and plans for nuclear , chemical , and biological defense programs . The ASD ( NCB ) develops policies , provides advice , and makes recommendations on nuclear weapons ; chemical , biological , radiological , and nuclear ( CBRN ) medical and non - medical defense ; safety , surety , security , and safe destruction of the current chemical weapons stockpile ; NCB arms control activities ; and related plans and programs . The ASD ( NCB ) also exercises oversight of the Cooperative Threat Reduction Program ( CTR ) executed by the Defense Threat Reduction Agency ( DTRA ) . In addition , the Director of DTRA reports directly to the ASD ( NCB ) . Prior to the signing of the National Defense Authorization Act for Fiscal Year 2011 on January 7 , 2011 , the ASD ( NCB ) was known as the Assistant to the Secretary of Defense for Nuclear & Chemical & Biological Defense Programs . History . The ASD ( NCB ) can trace its roots back to the beginning of the Cold War , when the Atomic Energy Act of 1946 ( P . L . 79 - 585 ) established an Atomic Energy Commission ( AEC ) to replace the Manhattan Project . The Act also created the DoD " Military Liaison Committee " ( MLC ) to coordinate military requirements with the AEC . According to an official history , " The MLC functioned as the authorized channel of communication between the DoD and the DOE on all atomic energy matters relating to the military applications of atomic weapons or atomic energy . It addressed matters of policy , programming , and commitment of funds to the military application of atomic energy . " Amendments to the Atomic Energy Act of 1949 ( P . L . 81 - 347 ) provided that the president appoint the chairman of the committee , with the advice and consent of the Senate , and that the Secretary of Defense choose the committee members . In 1951 , the Secretary of Defense moved the MLC to the Pentagon and designated its chairman as the " Deputy to the Secretary of Defense for Atomic Energy Matters " . In 1953 , this position was re - designated under DoD Directive 5130 . 2 as the " Assistant to the Secretary of Defense for Atomic Energy " . The National Defense Authorization Act for Fiscal Year 1987 ( P . L . 99 - 661 , passed in November 1986 ) abolished the " Military Liaison Committee " and replaced it with the " Nuclear Weapons Council " . A little over a year later , in December 1987 , the National Defense Authorization Act for Fiscal Years 1988 - 1989 ( P . L . 100 - 180 ) , established the statutory position of " Assistant to the Secretary of Defense ( Atomic Energy ) " . In 1994 , the ATSD ( AE ) was given control over the Defense Nuclear Agency ( DNA ) , now known as DTRA . In February 1996 , the National Defense Authorization Act for Fiscal Year 1996 ( P . L . 104 - 106 ) officially redesignated ATSD ( AE ) the " Assistant to the Secretary of Defense for Nuclear & Chemical & Biological Defense Programs " , or ASTD ( NCB ) . Between 1997 and 2001 , the Clinton administration declined to nominate anyone to serve as the ATSD ( NCB ) , having determined , as part of the Defense Reform Initiative , that the position should be eliminated . Congress , however , insisted that the Pentagon maintain the office , arguing it was necessary to ensure appropriate senior - level policy oversight and implementation guidance within the DoD . In January 2011 , President Obama signed the National Defense Authorization Act for FY 2011 , renaming the ATSD ( NCB ) the Assistant Secretary of Defense for Nuclear , Chemical & Biological Defense Programs . Office Holders . The table below includes both the various titles of this post over time , as well as all the holders of those offices .