In World War One, what were the negative effects on the enemy for gas masks?

Lachrymator - tear gas. This caused temporary blindness and serious irritation to the nose and throat of the victims.

Sternutator gasses - poisonous gas, chlorine, phosgene and diphosgene. Chlorine gas mixes with moisture so it will attack the eyes and lungs.

Suffocating gasse s - Caused severe edema of the lungs and death from asphyxiation could come within hours.