Gas mask

Gas masks are a mask designed to prevent the wearer from succumbing from airborne pollutants or toxic gases.

History
Solid Snake, during Operation Intrude N313, procured a gas mask to go through some of the gassed areas of Outer Heaven's fortress.

During the Zanzibar Land Disturbance, Solid Snake had to utilize a gas mask again to get through some areas that were either gassed or contained biological agents. The mercenary Running Man also utilized a gas mask during his encounter with Solid Snake. The Zanzibar Land personnel working in the Biologics Laboratory in the Highlands of the Zanzibar Fortress also utilized gas masks in case an alert was raised so they don't inhale the gas release.

The FOXHOUND member Psycho Mantis wore a gas mask in an attempt to both disguise his disfigured face as well as to focus his psychokinetic abilities. The NBC Unit of the Next-Generation Special Forces utilized gas masks.

In-game descriptions
"Gas Mask Required for the gas room."

- Gas mask description from Metal Gear