Swamp Gas

 is a condition in Fallout 76 and Fallout: The Roleplaying Game.

Fallout 76
can be inflicted by a diseased bloatfly, and results in -2 CHR.

Fallout: The Roleplaying Game
can be inflicted by any of the random causes of disease denoted in the Core Rulebook, and results in +1 difficulty on CHA tests.

Appearances
appears in Fallout 76 and Fallout: The Roleplaying Game.