The gas mask prevents infection by diseases from airborne sources. It can be worn together with any headwear that does not possess a mask feature.
- One can be found inside the Charleston landfill in the northern Ash Heap, located inside of the southernmost destroyed trailer home.
- One can be found inside the Charleston Fire Department in the Overseer's cache in the lobby, which is the first room when entering the building from the south parking lot.
- Four can be found at Knife Edge - Two on the lookout tower and two on a wooden shelf underneath a tent.
- Located next to Pleasant Valley Ski Resort's vendor bot.
- Three can be found at the Poseidon Energy Plant WV-06:
- One be found inside the armored personnel carrier in front of the plant on the western side, being worn by a skeleton.
- Two can be found in an open APC near the main entrance, on some crates.
- One can be found at Sunrise Field, in the flooded house, on the top floor, inside the bedroom, next to the bed.
- One can be found in a shack outside of Berkeley Springs.
- One can be found on a skeleton in a porta potty near the north side of Prickett's Fort.
Unequipping the gas mask may not remove the penalty to Perception. [verified]