There was "chemical warfare" propaganda just before the attack, like this hilariously fake (with sound effects from a 2012 Finnish military training on YT) video of "Polish speaking saboteurs killed while trying to blow up a chlorine tank" in like Donbas, and another very half-assed provocation in Crimea involving a chemical plant or whatever. It just quickly become forgotten as they try throwing ever other shit on the wall non stop.