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Gas mask

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MG1 gas mask

Gas mask used by Outer Heaven forces.

A gas mask is a mask put on over the face to protect the wearer from inhaling airborne pollutants and toxic gases.



In 1995, FOXHOUND member Solid Snake located a gas mask in Outer Heaven and used it to pass through some of the gassed areas of the fortress, during the Operation Intrude N313. He did so again during the Zanzibar Land Disturbance in 1999 for similar purposes.

Psycho Mantis of FOXHOUND wore a gas mask to disguise his disfigured face, as well as to focus his psychic abilities, even as a child during the Phantom Pain incident. The gas mask also acted as the reason why he avoided succumbing to FOXDIE despite his being a target.

The NBC troops of the Next-Generation Special Forces utilized gas masks while stationed in the warhead storage building of Shadow Moses Island, during FOXHOUND's revolt in 2005. They did so due to their use of chemical weapons in the presence of nuclear warheads.[1] The black-uniformed Genome Soldiers who ambushed Snake on several occasions, also wore gas masks. During his infiltration of the facility, Solid Snake procured a mask for himself, a double eyepiece model with the eyepieces being specifically treated to prevent fogging, the exterior being made of reinforced plastic, the interior being made of acetate weave, and included a voice emitter, in order to reach the research lab of Dr. Hal Emmerich.

Peace Sentinel

During the Peace Walker Incident in 1974, the armored vehicle escorts of Peace Sentinel and their commanders wore gas masks. These would protect against the inhalation of smoke released by some vehicles during an enemy attack.

Spoiler warning: Plot or ending details for Metal Gear Solid V: The Phantom Pain may follow.


During the 1980s, the Soviets and the various PFs operating in Afghanistan and Africa, respectively, occasionally donned gas masks to prevent chemical weapons such as sleep gas mines or sleep gas grenades from knocking them out.


Certain XOF operatives donned militiary facepiece respirators during the Hospital Escape in anticipation of the Man on Fire. Later, during the end of the Phantom Pain Incident, every member of the squad sent in to retrieve Sahalentropus from the child soldiers again wore these respirators to combat the vocal parasite outbreak Eli unleashed to ward them off. 

Kingdom of the Flies

Eli and his child soldiers wore gas masks that covered their nose and mouth, similar to the ones Diamond Dogs wore, as they had released the parasite on the island they were at.

Diamond Dogs

Gas masks that cover only the nose and mouth were used by the Diamond Dogs during a parasite outbreak at the quarantine facility of Mother Base, in order to prevent the parasites from infecting them via airborne infection. A squad of soldiers sent to investigate wore these, although they were later killed by the infected personnel (and in the case of one, ended up infected via wound transmission). Venom Snake would later wear this gas mask when he ended up personally going over to the quarantine facility and trying to find a cure and, if there was none, mercy killing the various infected personnel.

They would later don the same masks when confronting Eli and his "Kingdom of the Flies" in Africa, due to Eli and the various child soldiers under his command causing a parasite outbreak on the island.

Spoilers end here.

Zanzibar Land


Gas mask used by ZL forces.

In the late 1990s, Zanzibar Land troops utilized the M18-A2 gas mask, which was equipped with a cartridge-type filter that could last for over 70 days, a voice emitter so as not to impair speech, and was water permeable. Masks were issued to personnel operating in the research areas, in case gas was released during an intruder alert.

The mercenary Running Man wore a gas mask in his battle with Solid Snake during the Zanzibar Land Disturbance, having released nerve gas into the surrounding area prior to their battle.

Behind the scenes

"Required for the gas room."
―Gas Mask description in Metal Gear

The Gas Mask is a recurring item in the Metal Gear series. It first appeared in the original Metal Gear, and when equipped, would halt depletion of the player's Life gauge while operating in gassed areas. In later games, the mask instead reduces the depletion rate of the O2 gauge (introduced in Metal Gear 2: Solid Snake), and eventually the Life gauge, and so cannot be used indefinitely.

"Doubles the length, and slows the depletion of the O2 gauge in poison gas areas. Also works against gas grenades."
―Gas Mask description in Metal Gear 2: Solid Snake
"Reduces speed of O2 gauge decrease in poison gas environments."
― Gas Mask description in Metal Gear Solid
"Gas Mask
Reduces speed of O2 Gauge decrease in poison gas environment.
― Gas Mask description in Metal Gear Solid: The Twin Snakes

Gas Masks, based on the one Psycho Mantis originally used, were also available from the rewards shop of Metal Gear Online. They came in a variety of colors. In addition, bonus-colored Gas Masks based on the Kerotan and GAKO were also given out to players who attended the 2 year anniversary of the game on June 8th, 10th, 12th, and June 9th, 11th, and 13th, respectively.


  • Metal Gear 2: Solid Snake - User's Manual


Notes and references

  1. ^ Metal Gear Solid, Konami Computer Entertainment Japan (1998).
    Solid Snake: It looks like they're equipped with gas masks. // Meryl Silverburgh: That's because they are not supposed to use heavy arms. // Snake: Ah. You mean they use chemical weapons, instead.

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