The country that gave up the world’s fourth-largest nuclear arsenal

The Semipalatinsk Test Site, known as “the Polygon”, covered a vast area of steppe in north-eastern Kazakhstan. It was the Soviet Union’s main nuclear testing ground.

Forty years of tests

The first Soviet atomic bomb exploded there in 1949. Over the next four decades the site hosted 456 nuclear explosions: 116 in the atmosphere or above ground, and 340 underground.

People lived nearby throughout. An estimated 1.5 million were exposed to radioactive fallout. Studies of affected communities have found higher rates of cancer, birth defects and genetic damage, with one study finding about 80% more mutations in certain regions of DNA among exposed families.

A poet’s movement

In 1989, the Kazakh poet Olzhas Suleimenov used a television appearance to call for a protest against testing. Thousands responded, founding the Nevada-Semipalatinsk movement, named to link victims of nuclear testing in both the Soviet Union and the United States. It became one of the largest grassroots movements in the late USSR.

On 29 August 1991, the Kazakh leadership closed the test site by decree. The UN later declared 29 August the International Day against Nuclear Tests.

Giving it all up

When the Soviet Union collapsed, Kazakhstan suddenly held about 1,400 nuclear warheads, the fourth-largest nuclear arsenal in the world. It chose to give them up, transferring warheads to Russia and dismantling infrastructure with international help, and joined the Non-Proliferation Treaty as a non-nuclear state.

It remains one of the few cases in history of a country voluntarily giving up nuclear weapons, decided in a country that had seen their effects on its own people.