Stumm Gas caused nausea and unconsciousness. In one case in every 250 it was fatal.
Its use was banned in open areas.
Block Mania Game
If drawn, the phasing player must choose one interior square containing a blocker. The stumm gas immediately spreads to any adjacent internal square. Rolling 1d6, any blocker is removed from play on a 1-4.
Dredd: The Card Game
Stumm Cannon could be issued to a vehicle resource.