Hot cells, used to reprocess reactor fuel to make plutonium for nuclear weapons, begin operation in Argentina. They will remain in operation, without safeguards, through 1972.

A bomb is accidentally dropped on the deck of the nuclear-powered aircraft carrier USS Enterprise, killing 25 and wounding 85 crewmen.

President Richard Nixon announces the deployment a missile defense system called "Safeguard" to protect U.S. ICBM fields from attack.

First Strategic Arms Limitation Talks (SALT I) between the United States and the Soviet Union, begin in Helsinki, Finland. During these talks, each side gains a better understanding of the other side's views, and of the range of questions to be considered for how to achieve arms reductions. These discussions set the stage for the main round of talks, which open in Vienna in April 1970.