It's a bit hard to say for sure since it is all classified info for the most part. This article cites one of the creators for claiming it could last for years h

It's a bit hard to say for sure since it is all classified info for the most part. This article cites one of the creators for claiming it could last for years https://www.independent.co.uk/news/science/novichok-nerve-agent-how-salisbury-amesbury-incident-happen-explained-latest-a8433166.html https://www.independent.co.uk/news/science/novichok-nerve-ag...