I agree. From what I've read, the gas used in the attacks in 2013 (March & August) had the same hallmarks, and were said to have likely come from stockpiles of the Syrian military. If Assad was responsible for those earlier attacks, he certainly didn't face any consequences for them. So hell, if I'm Assad, and I've already gotten away with fooling the world twice before, why wouldn't I do it again?
http://www.naturalnews.com/041883_Syria_chemical_weapons_sodium_fluoride.html
Syrian chem attack in 2013 was...
wait for it...
sodium fluoride.