Thirty-one people, all of whom were onsite emergency response personnel, died as a result of the accident. Two workers were killed by an explosion. Twenty-nine were killed by acute effects of radiation exposure, and 203 were hospitalized with radiation sickness. More than 36 hours elapsed after the accident before the 135,000 people living within a 20-mile (32 km) radius of the plant were told to evacuate.

Although very large amounts of fission products were released, no one outside the Chernobyl site boundary was reported to have suffered any symptoms of direct radiation sickness. The relatively low radiation doses offsite were the result of the fission products being carried high up into the atmosphere by the explosion and resulting fire.