What is a stifle

I've read in a dictionary that a stifle is the joint next above the hock in the hind leg of a quadruped (such as a horse or dog) corresponding to the human knee. Also to stifle means to prevent something from happening and to feel unable to breathe. There is a sentence where I can't get the meaning of this word:

Company after company dashed into the blazing "fireproof" building, urged by the hoarse profanity of the chief. Twenty or thirty men must have disappeared into the stifle from which the police retreated. There was no haste, no hesitation. Everything moved as smoothly as if by clockwork.

The speaker's discribing the action of a fire. How it happened. Maybe those men died from the lack of air?

Solution 1:

The extract appears to be taken from an article or story titled "The Firebug" in "The Cosmopolitan", Volume 52, at p572 (Schlicht & Field, 1912) Google Books has a "snippet view".

From the definition below, I assume that "stifle" here is an extended meaning of

OED 3. (n.) 1886 J. Barrowman Glossary of Scottish Mining Terms 64 Stifle, noxious gas resulting from an underground fire.

i.e. the noxious atmosphere (smoke and fumes) inside the burning building.