If it will really happen (I hope that no), how West would react to it? Last month Biden said that US and NATO would respond to it.
There are unconfirmed reports that some "substance" was released from a drone. Could be false (calling Basurin's bluff), not sure.
Funny (not really) thing about Basurin and other DNR/LNR nutjobs - Russia can claim that these "independent" states haven't signed any international agreements regarding chemical weapons. And when I say "can", I mean Kremlin trolls are already doing it in comments on Russian sites, coming soon to Reddit/Youtube/etc.