In fact, the initial evidence in other countries that a major release of radioactive material had occurred came not from Soviet sources, but from Sweden, where on 28 April, workers at the Forsmark Nuclear Power Plant (approximately 1100 km from the Chernobyl site) were found to have radioactive particles on their clothing.
It was Sweden's search for the source of radioactivity (after they had determined there was no leak at the Swedish plant) that led to the first hint of a serious nuclear problem in the Western Soviet Union. In France, the government then claimed that the radioactive cloud had stopped at the Italian border. Therefore, while some kinds of food (mushrooms in particular) were prohibited in Italy because of radioactivity, the French authorities took no such measures, in an attempt to appease the population's fears (see below).
Contamination from the Chernobyl disaster 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. A large area in Russia south of Bryansk was also contaminated, as were parts of northwestern Ukraine.
203 people were hospitalized immediately, of whom 31 died (28 of them died from acute radiation exposure). Most of these were fire and rescue workers trying to bring the disaster under control, who were not fully aware of how dangerous the radiation exposure (from the smoke) was (for a discussion of the more important isotopes in fallout see fission products). 135,000 people were evacuated from the area, including 50,000 from the nearby town of Pripyat, Ukraine. Health officials have predicted that over the next 70 years there will be a 28% increase in cancer rates in much of the population which was exposed to the 5–12 EBq (depending on source) of radioactive contamination released from the reactor.
Soviet scientists reported that the Chernobyl Unit 4 reactor contained about 180–190 metric tons of uranium dioxide fuel and fission products. Estimates of the amount of this material that escaped range from 5 to 30%. Because of the intense heat of the fire, and with no containment building to stop it, part of the ejected fuel was vaporized or particulized and lofted high into the atmosphere, where it spread.
Workers and "liquidators" Evacuation. Civilians. Plant and animal health. Suggested long-range effects.