The Russian chemist who invented the Novichok poison and then fled to the United States, Vil Mirzayanov, shared his findings on his blog on how they could have poisoned Alexey Navalny:
“I gave interviews to various channels all day. Regarding the poisoning of the city of Navalny. My version: a substance from the novice class, codenamed A-242, was used. It is already solid, which can be turned into powder. This substance is almost 10 times stronger than the substance A-230, which is liquid and which was adopted as a chemical weapon by the Soviet Army. Substance A-242 is needed up to 10 mg to kill a person. They could have put it in a tea bag.
The vapor pressure of A-242 is very low and therefore does not pose a hazard when it is in a tea bag with tea. In any case, the OM got into the victim's digestive tract. For this reason, Mr. Navalny could not pose a danger to those around him. He showed several channels from his book the chemical formula of substance A-242. And then, you know, Maria Zakharova complained that she did not know the formulas. I am still ashamed that I had to work on chemical weapons.
As for the arguments that these substances were synthesized so long ago that they are unlikely to survive. However, the International Convention on the Prohibition of Chemical Weapons permits scientific work in the field of organic matter and even accumulates almost 200 kg of organic matter. I was against this trick. Most likely, GosNIIOKhT is still quite legitimately investigating these newcomers and, naturally, synthesizes them for various experiments. For this reason, GosNIIOKhT came under sanctions. And rightly so. We ought to cover it up once and for all..."