A gas mask is a device that was made and created by an American named Garrett Morgan, in 1914. The gas mask is designed to simply protect someone from poisonous, toxic, and quite deadly gases. How it works is that it simply covers and seals itself around someones face. Covering the mouth, nose, and sometimes the eyes. Depending on the type of gas mask you have, it would provide fresh and pure oxygen through a tube that is connected from the mask to a respirator which holds and contains the purified oxygen.