The Threshold Test Ban Treaty enters into force.
A nuclear warhead on the cruiser USS Albany is damaged (this type of incident is codenamed Dull Sword).
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.
A.Q. Khan is given full control over Pakistan's uranium enrichment program. Khan develops the Engineering Research Laboratory.