Early deaths at Chernobyl
The personnel present near the reactor when the Chernobyl accident occurred and the emergency crews who intervened at the peril of their lives in the first moments were the most exposed. In total, 163 people received very strong irradiations, similar or superior to one sievert. Of these 163 people, 28 died as a result of this exposure in the days and weeks that followed. Among survivors, 11 additional deaths have been observed for the period 1988-1998, including 8 for diseases that have no connection with ionizing radiation.
Source IRSN