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April 27, 1986

Untitled notice on levels of radiation in Chernobyl NPP and steps taken in response

This document was made possible with support from Carnegie Corporation of New York (CCNY)


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As of 8 o’clock on the April 27th, 1986, changes were detected in the radiation environment in the 3rd and 4th energy blocks of the Chernobyl atomic energy station.


The level of gamma radiation particles is up to 1000 microroentgens per second. On the rest of the territory of the station it is up to 15-200 microroentgens per second, and at the city limit it is up to 6-18 microroentgens per second.


There are 100 persons in the medical institutions of Pripyat, of whom two are in a critical condition. According to a decision by the Commission of the USSR Ministry of Health, 26 injured persons have been sent by airplane to Moscow for additional examination and treatment.


According to a decision by the Government Commission headed by the USSR Council of Ministers Deputy Chair Comrade B.E. Shcherbinoi, [operation at] energy blocks # 1 and 2 has been halted with a shut-down cooling of the reactors.


On the 26th of April, 1986 a criminal case was opened by the Prosecutor of Kiev Oblast on the accident at the Chernobyl atomic energy station. An intelligence investigation team is continuing its work with members of the 6th Administration [handwritten above: “and Investigation Department”] of the KGB in cooperation with the Special Departments, offices of the Ministry of Internal Affairs and the prosecutor’s office with the use of covert agents and trusted individuals.


No information about possible sabotage or responsibility for the accident was received from the units’ records management or persons verified by signals.


Necessary measures have been taken by Party and Soviet agencies for the possible evacuation of the city. In particular, 1,100 buses and 2 Diesel trains have been prepared and concentrated in the area of Chernobyl. A reserve of 1,500 police officers has been established as an escort to ensure safety and order.


Covert teams from the KGB Administration and UVD [Administration of Internal Affairs] were sent into the Polesskoe and Chernobyl districts, and outlying areas of evacuation.


According to an agreement with Party agencies, measures were taken to prevent distribution of information about the occurrence and panicky rumors.


Measures are being taken to determine the center of the accident with the use of helicopters. Radiation and chemical defense troops have been activated for this same purpose.


We are controlling the situation in Pripyat and the surrounding area.


Information has been given to the KGB of the USSR.



The document refers to the level of radiation in the area affected and the measures undertaken for planned evacuations.


Document Information


HDA SBU, f. 11, spr. 992, t. 29. Originally published by the Center for Research into the Liberation Movement (TsDVR) together with the Ivan Franko National University of Lviv at


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Carnegie Corporation of New York (CCNY)