Poisonous Gas

Nuisance Hazard (Levels 1–4)

Poisonous gas is usually encountered in an enclosed space, such as a sewer or sealed tomb. The gas fills as much space as it can, up to a maximum of ten 10-foot Cubes. The transparent gas carries a foul odor. The gas is continuously or periodically replenished by some natural or magical source, though a strong wind disperses the gas for 1 minute.

Any creature that enters poisonous gas for the first time on a turn or starts its turn there makes a DC 12 Constitution saving throw, taking 5 (1d10) Poison damage on a failed save or half as much damage on a successful one. Creatures in the gas also have Disadvantage on Death Saving Throws.

At Higher Levels. You can scale the hazard for higher levels by increasing the Poison damage and the save DC, as shown in the following table.