Chernobyl Disaster

Quick facts

• On 26 April 1986, reactor Unit 4 at the Chernobyl (Chornobyl) Nuclear Power Plant near Pripyat (then Ukrainian SSR) exploded during a safety test, destroying the reactor core and starting fires that released large amounts of radioactive material. (ChNPP; UNSCEAR).
• The explosion and subsequent fire released radioactive contamination across Europe but most heavily affected large areas of Belarus, the Russian Federation and Ukraine. Protective actions (evacuations, food restrictions) and the creation of the Exclusion Zone followed. (WHO; UNSCEAR).
• A substantial group of plant staff and emergency workers received very high doses: UNSCEAR reports about 134 people on site received high doses of radiation, with 28 dying within the first three months; further fatalities among emergency and recovery workers were recorded thereafter. (UNSCEAR).
• Hundreds of thousands of cleanup and recovery workers (often called 'liquidators') were involved: initial estimates put about 350,000 liquidators in 1986–87, later registries include up to ~600,000 people. The UN Chernobyl Forum estimated that, among the several hundred thousand most highly exposed people, up to about 4,000 eventual excess cancer deaths could occur (estimates vary by method and time horizon). (WHO; Chernobyl Forum / IAEA).
• The clearest documented long-term health consequence is a large increase in thyroid cancer among those exposed as children and adolescents from radioactive iodine (131I) intake; thousands of thyroid cancer cases in that cohort have been diagnosed and are very likely linked to the accident. (UNSCEAR; WHO).