There is no attempt by Fisk to challenge this. He simply reports it, uncritically.
(I have previously posted images of this. This time I shall refrain).
Fisk does not fact check these claims with other doctors outside of Syria.
Can dust inhalation cause these injuries?
But he simply (conveniently) finds more people who deny there was a chemical attack.
His use of the word "troglodyte" is accurate, but subtly suggests the same "gunmen" (not women or children) are primitive.
He uses his failure to find any critics as evidence that the people must surely be being truthful.