After the 1963 Limited Test Ban Treaty, the United States conducted all such tests underground.

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But in 1963 the Limited Test Ban Treaty prohibited any nuclear explosion that sent radioactivity over a nation's borders.

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These include the ABM Treaty, the Limited Test Ban Treaty and chemical weapons conventions as well as other international agreements such as the Helsinki Final Act.

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He also negotiated a limited nuclear test ban treaty that inhibited the proliferation of weapons of mass destruction.

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