It increased the authority of the Secretary of Defense, who was authorized to establish such defense agencies as he thought necessary "to provide for more effective, efficient and economical administration and operation". The first field agency established under the act was the Defense Atomic Support Agency (DASA), which replaced the AFSWP on 1 May 1959. The new agency reported to the Secretary of Defense through the Joint Chiefs of Staff, and was given responsibility for the supervision of all Department of Defense nuclear testing, which had hitherto been handled by the individual services.