1976

March 31
Threshold Test Ban Treaty enters into force.

April 16
A nuclear warhead on the cruiser USS Albany is damaged (this type of incident is code-named Dull Sword).

May 28
President Gerald Ford and General Secretary Leonid Brezhnev sign the Underground Nuclear Explosions for Peaceful Purposes (PNE) Treaty, which limits individual explosions to 150 kilotons and multiple explosions to 1,500 kilotons. The Treaty closes the gap left by the Threshold Test Ban Treaty regarding the distinction between nuclear weapons testing and explosions for peaceful purposes. Although the Treaty has never been ratified, both states have agreed to honor its terms.