it makes no sense for assad to piss off the world by doing something he didn't need to. he's western educated, he understands that dead babies always gets the west involved (unless they're black babies).
my first thought was the rebels got a hold of a canister and lit it up in that area. it's in their best interests not his.
then i read something that could have been complete bullshit, that said that someone from a chem missile base did launch it without informing the boss.