Federal Civil Defense Administration

The Federal Civil Defense Administration (FCDA) was organized by President Harry S. Truman on December 1, 1950 through Executive Order 10186, and became an official government agency via the Federal Civil Defense Act of 1950 on 12 January 1951. In 1958 the FCDA was superseded by the Office of Civil and Defense Mobilization when President Dwight D. Eisenhower merged the FCDA with the Office of Defense Mobilization.
In its early years, the agency focused on evacuation as a strategy.
The FCDA was first headed by Millard Caldwell under Truman, then Val Peterson under Eisenhower.
Background.
The predecessor to the FCDA, the Office of Civilian Defense was abolished in June 1945 with the end of World War II. In the period between the end of the World War and 1949, when the Soviet Union detonated their first atomic weapon, little was given to the topic of civil defense. After the Soviets demonstration of their first atomic weapon there was a feeling of the need to "do something" throughout both the American public and government. This led to, among many actions, the creation of the Federal Civil Defense Administration by President Harry S. Truman in 1950.
A purported website address for this government organization (rendered as "The F.C.D.A.") was briefly referenced in the 1998 American science fiction film "Deep Impact" at time marks 0:54:26, and 1:18:50, using a fictional website listed in the movie audio monologue and subtitles as "http://fcda.gov/". This seemingly fictional website (as used in the movie) has "not" been known to ever exist, and the Internet Archive and WHOIS databases carry no record of it being for any organization or government.