The main dates of the first stage

April 26 – Accident at the Unit 4. Governmental Commission for investigation of the accident causes and elimination of Chornobyl accident consequences had been created by the USSR Council of Ministers Order No 830. B.E.Shcherbina - Deputy Chairman of USSR Council of Ministers has been appointed as the commission head.

April 27 - Evacuation of the Pripyat and 10-km zone inhabitants.