... acid, cyanogens chloride, arsine, phosgene, chloropicrin, bromomethane, lewisite gas, mustard gas, sarin, vx gas, toxic smoke, and fume, benzene, hydrogen phosphide, chlorine, acetone, ... 21kg 4.Usage maintenance and maintain4.1.The selection of gas mask 4.1.1. checking the position between glasses and ... a right selection. 4.2.The procedure of wearing gas mask 4.2.1. adjusting the position of fillets ...