According to this report, we should celebrate the 20th anniversary of the Chemical Weapons Convention:
Since the CWC went into effect, over 95% of all declared chemical weapons have been verifiably eliminated.
What the report fails to discuss is the fact the CWC did nothing to eliminate undeclared chemical weapons, such as novichok. You can read about this undeclared weapon here:
In reality the current hub-bub over chemical weapons in Syria is BULLSHIT. The real threat is from offshoots of the Soviet Foliant Program, and the potential target of that threat is you and me. If novichok ever falls into the wrong hands, we are screwed.
If and when that happens, keep in mind the US could have demanded that novichok get added to the list of proscribed chemical weapons, but did not.