Two days prior to the leak Mikhail Mizintsev, the Chief of Russia's National Defense Management Center claimed that Ukrainian nationalists were plotting a false flag chemical attack in Sumy. Mizintsev alleged on 19 March that mines had been placed in chemical storage facilities at the plant to poison residents in case of Russian troops advancement into the city. He also alleged that a secondary school was similarly sabotaged in Kotlyarovo, Mykolaiv Oblast.[4]
Leak
The leak was first reported at about 4:30 am local time on 21 March 2022 at the Sumykhimprom chemical plant, located in the suburbs of Sumy.[4]