In the US, the best news reports about this I've seen are on
CBS News,
The Washington Post, and the The New York Times. (The Post & The Times both require logging in, I do subscribe to the Post, but not the Times.) However they all follow
what I see on the BBC.
When I was in the Navy, we got some brief training on chemical & biological warfare agents. Nerve gas (as it was called then) was truly frightening. If you were exposed, you had seconds to jab your thigh with a syringe-pen containing epinephrine. We practiced that motion, without really sticking ourselves. Some guy, a bit slow-on-the-uptake, asked why we should stab our thighs without first removing our pants. The answer was "Sure, go ahead and pull down your pants. You'll have just enough time to kiss your ass goodbye."
That was both the bad news & good news about nerve agents back then. They acted dangerously fast, and in a short time, became inactive. It seems like the Russians have developed nerve agents that become activated only after delivery. And apparently, are slowly inactivated. That's their idea of "better living through chemistry".