The research, production, use and stockpiling of Chem/Bio are forbidden by international treaty. The Bio convention of 1972 and the Chem convention of 1993. Almost all countries in the world have ratified these agreements except a few "rogue states". The bio convention of 1972 was the first instrument to completely forbid not only the use but also to production and detention of complete class of weapons. The chem weapon convention has a specialized agency with inspectors (OPCW) that visit countries all over the world to make sure the convention is respected. The chem/bio weapons haven't been use massively since the Iraq-Iran war in the 80s. The last know case was Syria a few years ago and this lead to the destruction of the Syrian chem inventory under strong pressure of international community (mainly USA, France and UK). The truth is that Chem/Bio weapons are not very useful for main powers and too risky in term of PR for smaller nations. Actually USA lead the way when Nixon announced that USA would unilaterally stop producing and stockpiling bio weapons. The historic trend has always leaned toward less use of these weapons but the position of Russia is still unknown on this matter. I personally don't believe in any large scale event in the next 20-30 years and I think that no terrorist organization, even ISIS are capable of doing anything more that a symbolic Chem/Bio act of terror. Chem/Bio is a serious business and it took a long time for advanced states to produce and develop effective method of contamination. I don't buy the news hysteria about Chem/Bio but we must be prepared nevertheless. Last I would say that even if these weapons are mainly forbidden and not produced anymore, all countries maintains important funding and response units to face a potential attack. This is strictly defensive measure though.