Fallout - Vault 53
Ever since its invention at the beginning of the First World War, chemical warfare has become a standard – and horrific – aspect of battle. A gas mask or certain kinds of armor will lessen the effects of gas attacks, but if a character is caught unaware, she will be subject to the gas’ terrible poisons. the effects vary from chemical to chemical, and the radius of the gas cloud is given in the weapon’s description. The lasting effects of the gas continue from the round in which the gas disperses, if the character is still standing in the cloud.
There are two kinds of gas: the kind which must be inhaled to do damage and the kind that can cause damage just by skin contact.
The stats for each kind of armor will explain what kind of resistance each suit gives against the two kinds of gas. Sometimes an item, such as a gas mask, will give the user a degree of resistance against one kind of gas or another