In August 2026, Kazakhstan marks the 35th Anniversary of the closure of the Semipalatinsk Nuclear Test Site – one of the most momentous events in the country’s modern history, which profoundly shaped its national policy on nuclear disarmament and non-proliferation.
The history of the Semipalatinsk Test Site began on August 29, 1949, when the Soviet Union conducted its first nuclear test there. Over the following four decades, the site served as a primary proving ground for the USSR’s nuclear programme.
A total of 456 nuclear explosions were carried out on the territory of Kazakhstan, including atmospheric, ground-level and underground tests. This prolonged testing activity resulted in extensive radioactive contamination of the environment and caused severe long-term consequences for the populations of adjacent regions. According to estimates by Kazakh state authorities, more than 1.3 million people were exposed to radiation.
On August 29, 1991, the Semipalatinsk Nuclear Test Site was officially closed by a Decree of the President of the Republic of Kazakhstan. Subsequently, at Kazakhstan’s initiative, the United Nations General Assembly proclaimed August 29 as the International Day against Nuclear Tests.
Kazakhstan cemented its status as a non-nuclear-weapon State by voluntarily renouncing the world’s fourth largest nuclear missile arsenal, inherited from the Soviet Union. This arsenal included more than 100 intercontinental ballistic missiles, 1,040 nuclear warheads, 40 strategic bombers, and over 300 warheads for cruise missiles.
The environmental and humanitarian legacy of the Semipalatinsk Test Site continues to hold relevance for Kazakhstan’s current state policy. Thirty-five years on, rehabilitation efforts in the region have transitioned from an active closure phase to a stage of in‑depth scientific research and long‑term environmental monitoring.
The closure of the Semipalatinsk Test Site is a historic milestone for Kazakhstan and a compelling reminder of the imperative to prevent nuclear testing and the spread of nuclear weapons. The decision taken in 1991 proved to be a pivotal step in shaping the foreign policy course of an independent Kazakhstan.
Today, Kazakhstan continues to steadily expand its engagement with all United Nations Member States on issues related to nuclear disarmament, non‑proliferation, and the peaceful use of nuclear energy. Kazakhstan also advocates for the strengthening of the nuclear non‑proliferation regime, the development of international cooperation in this field, and the swift entry into force of the Comprehensive Nuclear‑Test‑Ban Treaty (CTBT).
The experience of the Semipalatinsk Test Site retains lasting international significance, serving as a stark reminder of the long‑term humanitarian and environmental consequences of nuclear testing, and underscoring the need for collective efforts to ensure international security and protect future generations.
The Republic of Kazakhstan – as one of the few countries in the world to have directly endured the consequences of nuclear testing – remains a steadfast proponent of nuclear disarmament and calls upon all States to strictly observe the regime of non‑proliferation of weapons of mass destruction.