My guess is that a lot of the gas that is probably still in the same barrels that are 10,15,20 years old is starting to leak and may be unstable as well as useless. It has to cost quite a bit to maintain such an arsenal that has low pr value when used and is probably a nightmare to move.
Getting rid of the gas is probably a big plus for Assad. It may take the other terror types a while to figure that one out.
That's most likely true. As for the others - ooops!