Despite their agreement to the '93 and '97 Chemical Weapons Conventions, they're known liars. Perhaps the 3rd party Syrian access is their excuse for not actually having them, but maintaining the option for their use.
See, if I was Israel, I wouldn’t go after their weapons. I would go after their parliment and every radical cleric that is spouting this stuff.
Take away their entire C&C capability and assassinate every radical. In the second hour I would take out Hizbollah and Hamas leadership in Lebanon, Gaza and elsewhere. In the third hour, push everyone from Gaza into Egypt and consolidate there.
Now go to the UN and announce I want peace.