The report prepared by the Chernobyl Forum, led by the (IAEA) and (WHO), attributed 56 direct deaths (47 accident workers, and nine children with ), and estimated that as many as 9,000 people among the approximately 6.6 million most highly exposed, may die from some form of cancer. Specifically, the report cited 4000 cases among children diagnosed by 2002.
Although the and certain limited areas will remain off limits, the majority of affected areas are now safe for settlement and economic activity.
Causes
There are two conflicting official theories about the cause of the accident. The first was published in August 1986 and effectively placed the blame solely on the operators. The second theory, proposed by and published in , attributed the accident to flaws in the design, specifically the . Both commissions were heavily by different groups, including the reactor's designers, power plant personnel, and by the Soviet and Ukrainian governments. The IAEA's 1986 analysis attributed the main cause of the accident to the operators' actions. But in January 1993, the IAEA issued a revised analysis, attributing the main cause to the reactor's design.
A conflating version holds that the operators were not informed about problems with the reactor. According to one of them, Anatoliy Dyatlov, the designers knew that the reactor was dangerous in some conditions but intentionally concealed this information. In addition, the plant's management was largely composed of non-RBMK-qualified personnel: the director, V.P. Bryukhanov, had experience and training in a coal-fired power plant. His chief engineer, Nikolai Fomin, also came from a conventional power plant. Dyatlov, deputy chief engineer of reactors 3 and 4, had only "some experience with small nuclear reactors", namely smaller versions of the nuclear reactors that were designed for the Soviet Navy's nuclear .
Effects
The nuclear meltdown provoked a radioactive cloud which floated over , , and , but also the European part of , , , , , , , , , , , the and the , , , , , , , (including ) and the (UK). The initial evidence that a major exhaust of radioactive material was affecting other countries came not from Soviet sources, but from , where on April 27 workers at the (approximately 1100 km from the Chernobyl site) were found to have radioactive particles on their clothes. It was Sweden's search for the source of radioactivity, after they had determined there was no leak at the Swedish plant, which led to the first hint of a serious nuclear problem in the western Soviet Union. The rise of radiation levels had at time already been measured in but it had not been published.
Contamination from the Chernobyl accident was not evenly spread across the surrounding countryside, but scattered irregularly depending on weather conditions. Reports from Soviet and Western scientists indicate that Belarus received about 60% of the contamination that fell on the former Soviet Union. However, the stated that half of the volatile particles had landed outside Ukraine, Belarus and Russia. A large area in Russia south of was also contaminated, as were parts of northwestern Ukraine. In , measures were taken including seemingly arbitrary regulations pertaining to the legality of importation of certain foods but not others. In France some officials stated that the Chernobyl accident had no adverse effects – this was ridiculed as pretending that the radioactive cloud had stopped at the and borders.
In the immediate aftermath of the accident, two hundred and thirty-seven people suffered from acute radiation sickness, of whom thirty-one died within the first three months. Most of these were fire and rescue workers trying to bring the accident under control, who were not fully aware of how dangerous the exposure (from the smoke) was (for a discussion of the more important isotopes in fallout see ). 135,000 people were evacuated from the area, including 50,000 from Pripyat.
