JF Ptak Science Books Quick Post
The masks devised to deal with the gas attack of WWI were sometimes effective, sometimes not--and sometimes they were occasionally lethal enhancers. The earliest masks were creepy, unworldly, Coraline-like burlap-and-button-faced affairs--I'd hardly want to imagine seeing thousands of these guys come running up to me with rifles and grenades in their hands attacking my position (as we can see in the image below of an attacking British force at Loos in 1915).
And yes, of course, they started out as "anti-gas masks" because that is what they are--the "anti-" prefix is dropped not long afterwards.
And the attack on German lines at Loos, from the Illustrated London News, October 30, 1915: