It was rebels who stored chemical weapons in the Khan Sheikhoun warehouse. Syrian and Russian forces attacked it and therefore people were hit by the two chemical weapons: sarin and chlorine.
Former CIA officers say chemical attack in Syria wasn´t conducted by Assad nor by Russia. Sarin attack in Syria in 2013 was a false flag.
No evidence for these claims given. Zerohedge notoriously spreads unverifiable conspiracy theories. See the timeline of Syrian chemical weapons activity since 2012: bit.ly/2oNf0FO, // See the cover note for detailed debunk.