Public concerns about fallout made atmostpheric testing increasingly controversial through the 1950s. The US was already considering a moratorium when the USSR unilaterally suspended tests in March 1958, and the three nuclear powers agreed to a moratorium in October (France was not a party, and tested its first device in 1960). Testing was resumed in September 1961, but negotiations continued, resulting in the 1963 treaty banning signatories from conducting atmospheric tests.