Notable case, Kurčatov, Abai Region, Kazakhstan
Semipalatinsk Test Site
Семей ядролық сынақ полигоны
The Soviet Union's main nuclear test site, on the steppe of north-eastern Kazakhstan: between 1949 and 1989 more than 450 nuclear devices were detonated there, over a hundred of them in the atmosphere, with fallout on the surrounding villages.
At a glance
- Status
- Contained
- Area
- 1,800,000 ha on land1
- Activity
- 1949–1989
- People affected
- 1,500,0002
- Media
- soil, groundwater, surface water, living organisms
- Kind of site
- nuclear, military
- Area. About 18,000 km², the area of the whole test site (Wikipedia, read in 2026); contamination is concentrated at the testing grounds, not spread over the whole area.
- People affected. People exposed to fallout over the years according to estimates by Kazakh experts, as reported by Wikipedia.
Contaminants
Radionuclides
Status
Contained
The site is managed by the National Nuclear Center of Kazakhstan. Between 1996 and 2012 the tunnels and boreholes holding plutonium residues were sealed with concrete. According to Wikipedia (read in 2026), mining and farming have resumed on part of the area since 2014.
Story
On 29 August 1949 the Soviet Union detonated its first atomic bomb at Semipalatinsk. Hundreds of tests followed until 1989: Wikipedia reports both the count of 456 explosions (116 atmospheric and 340 underground, in tunnels and boreholes) and that of 468. The atmospheric tests took place on the "Experimental Field"; the underground ones in the tunnels of the Degelen massif and the boreholes at Balapan, where an explosion for civil purposes created Lake Chagan.
People living nearby were neither evacuated nor informed. Kazakh experts estimate that 1.5 million people were exposed to fallout over the years. In the late 1980s the Nevada-Semipalatinsk movement arose in Kazakhstan, demanding an end to testing; the site was closed on 29 August 1991.
After closure, accessible plutonium residues remained in the tunnels. Between 1996 and 2012 a joint operation by Kazakh, Russian and American engineers, kept confidential until it was finished and costing 150 million dollars, secured them by pouring special concrete into the boreholes and sealing the tunnels.
Timeline
- 194929 August: first Soviet atomic explosion.
- 1989Last nuclear test at the site.
- 199129 August: the test site is closed.
- 1996The Kazakh-Russian-American operation to secure plutonium in the tunnels begins.
- 2012October: the plutonium is secured, after 17 years and 150 million dollars.
Health
Wikipedia reports studies that found an 80% increase in DNA minisatellite mutations in people exposed between 1949 and 1956 and 50% in their children, and an excess of solid tumours (oesophagus, stomach, lung, breast, liver) and thyroid abnormalities. The original studies were not consulted for this record.
Remediation
- 2012sealing and containmentBetween 1996 and 2012 the Degelen tunnels were sealed and boreholes filled with special concrete to isolate plutonium residues.
From the literature
Species that acted on one of this site's contaminants in at least one study. The list is automatic and takes no account of this site's soil, concentrations or climate.
Fungi
- Cladosporium sphaerospermumRadionuclides (mixed)Evidence: laboratory
- Rhodotorula taiwanensisRadionuclides (mixed)Evidence: laboratory
Nearby
Sources
- Semipalatinsk Test Site, Wikipedia, 2026
- International Day against Nuclear Tests, 29 August, United Nations
- International Day against Nuclear Tests: history, United Nations
Draft compiled from public sources, not yet reviewed.