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Gas Chamber

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A purpose-built or improvised enclosed space used to kill through suffocation and/or the introduction of Deadly Gas. In movies about murders on death row, they are shown being strapped into a chair in the chamber. In fiction, villains may convert regular rooms or vehicles into gas chambers to trick their victims.

Infamously used by the Nazis during The Holocaust. Also employed as an execution method in several of The United States, and still on the books as a method of execution in six states, although no American prisoner has been gassed since 1999. States have largely shifted to lethal injection.


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    Anime and Manga 
  • Higurashi: When They Cry: This is what happens to Hinamizawa's population under the "Disaster of Hinamizawa" natural disaster coverup.
  • In an early chapter of the Lupin III manga, a guard said Lupin would be heading to the Gas Chamber. Inspector Zenigata knows that the method of execution at this particular joint is the electric chair and any guard would've known that. He has just enough time to figure out the guard is actually Lupin in disguise before Lupin uses this knowledge against him and he sets off to rescue the guard Lupin sent to be electrocuted in his place. This story was adapted into the Lupin III: Part 1 episode 'One Chance to Breakout'.
  • In Mobile Suit Gundam Wing, the Gundam Engineers have been captured by OZ and locked in a cell for some time. One OZ officer decides to kill them by cutting off the oxygen supply. When Doctor J realizes the air is getting thin, Professor G snarks "If you want to die, hurry up and do it, and save some oxygen for the rest of us!" They end up getting rescued by Lady Une.
  • Saber Rider and the Star Sheriffs had an episode in which Sabre Rider went to the Outworld and confronted the main baddie, who proceeded to suck the oxygen out of the room, as he himself didn't need it.

    Comic Books 
  • Batman: A Golden Age story has Batman pursuing four escaped criminals. Each of the convicts was condemned to die by a different method of execution in a different state. The one sentenced to die by gas chamber stows away on a ship in an attempt to escape. What he does not realise is that the ship is being sealed and fumigated with cyanide gas to kill the rats.
  • Hack/Slash: The first issue involves a kindly mentally disabled man who is accidentally killed in a veterinary euthanasia gas chamber as a result of a Deadly Prank, and comes back as a murderous Revenant Zombie.
  • In The Punisher: Circle of Blood, Punisher is dropped through a Trap Door into Trust's brainwashing chamber, and sedative gas is there to greet him. However, he easily escapes since he was dropped in with his gear, and the room was built with defenseless targets for "reidentification therapy" in mind.
  • In Supergirl's story Brainiac's Blitz, the titular villain sets a trap for Superman which involves locking him into a Kryptonite cage and filling it with Kryptonite gas.
  • Tintin in America had bandits drop Tintin into one through a Trap Door, before dropping his corpse in the Michigan. In the comic, they unintentionally used the wrong gas (a soporific) instead; in the animated version, there is no mention made of the soporific being a mistake (a drowning looks more "accidental"), and Tintin is rescued from the Lake by Snowy instead.

    Fan Works 
  • In the Kim Possible fanfic An Old Foe Returns, Mastermind attempts to test his formula that would diminish humanity's mental capacities on Kim and Ron through this manner. It's only through quick thinking and creativity that they escape.

    Film — Live-Action 
  • In Crime Doctor's Man Hunt, Natalie murders the two hoods who are attempting to blackmail by opening the valves on her gas fire and then leaving the room while they asphyxiate.
  • Deadly Detention: When the students end up in a small room together, white gas starts getting pumped into the room through the door.
  • Escape from Sobibór: The film's Awful Truth, a means by which most of the murdered prisoners die.
  • In Escape Room (2017), Conrad and Tabby are killed when the room they are in is filled with an acidic gas that causes their flesh to dissolve.
  • Escape Room (2019): The fourth room is a combination of different hospital rooms from the player's pasts; if they fail to figure out the puzzle within a few minutes, the room will fill with carbon monoxide.
  • Escape Room: Tournament of Champions: In the extended cut, Claire's Luxury Prison Suite doubles as another escape room, requiring her to solve a puzzle that only be completed with outside help. After three wrong tries, the room fills with poison gas.
  • Flash Gordon (1980): Our hero is executed in a gas chamber. He gets better.
  • Goldfinger: Auric Goldfinger arranges to kill all his criminal conspirators after they balk at his Evil Plan to irradiate the U.S. gold supplies at Fort Knox by excusing himself, at which point it's revealed that the entire planning room has been outfitted as a gas chamber with air-sealed doors.
  • I Want to Live!! Barbara is executed inside a gas chamber.
  • King Cobra (1999): The final plan to kill Seth involves luring him into a snake cage and gassing him.
  • The Man Who Changed His Mind: After switching Dick's mind into his body, Dr. Laurience starts filling the chamber his body is in in to kill Dick.
  • The unseen Big Bad of Police Academy 6: City Under Siege pulls this on Lassard when he reaches the meeting room, and Lassard is a little surprised he'd use such an old one:
    Lassard: Oh, come on! Poison gas??
    Villain: Yes, melodramatic I know, but effective.
  • Saw II had a gas house.
  • Son of Saul centers around a Birkenau Sonderkommando and shows the use of the gas chambers at Auschwitz.
  • Star Wars Episode I: The Phantom Menace features at the beginning the Nemoidan Trade Federation trying to gas the ambassador Jedi.
  • XXX has the villain Yorgi use a makeshift gas chamber to eliminate the scientists who developed his gas-based bioweapon. While the scientists are celebrating, he has the device activated and the room sealed off so he can watch them suffocate to death from the other side of the glass doors.

  • The Dream Park novel The Barsoom Project has a sealed room with a window air conditioner which runs backwards to suck the air out.
  • The poisoned candle trick shows up again in the Discworld novel Feet of Clay.
  • Another murderer used the poisoned candle M.O. in Edgar Allan Poe's The Imp of the Perverse.
  • The vacuum version is used in In Hero Years, I'm Dead involving a memorabilia room that the heroes are trapped in.
  • In Look to the West, gas chambers called "phlogisticateurs" are employed by the alternate French Revolutionaries to execute the more prominent enemies of the Republic, including King Louis himself. They are invented due to the work of Antoine Lavoisier, who takes his own life upon realising this. They use carbon dioxide and are not very efficient, only being used for particularly cinematic cases - most of the time the Revolutionaries use the Chirugeon, the in-timeline name for our guillotine. In a twist, the phlogisticateur technology later becomes used to create test greenhouses that allow the widespread cultivation of cinchona trees, meaning a ready supply of quinine to combat malaria in Africa. This is intended to be a similar case to the fact that in our own history, chemotherapy drugs came about as a result of research into poison gas in WW1.
  • The Raymond Chandler short story "Nevada Gas" uses the well-sealed backseat of a limousine.
  • In the Resistance trilogy by Clive Egleton, set in a Soviet-occupied Britain, La Résistance have promised someone passage on the Underground Railroad, but actually plan to kill him. So he and his girlfriend get in the back of a container truck and hide in the smuggling compartment, not knowing it's actually a gas chamber. The driver then turns on the cyanide gas, realising too late he hadn't instructions to kill the girl as well.
  • In Robert E. Howard's Conan the Barbarian story "Rogues in the House", a glass wall falls down in a room, and the dust of the gray lotus is used, which drives them murderously insane.
  • The original Sherlock Holmes short stories:
    • The "Devil's Foot" had a character place the title root—an obscure poison from Africa—into an oil lamp. The lamp was then lit, releasing the poison into the air and causing death and brain damage to the killer's victims. The murderer is later killed in the same way himself. This one nearly killed Holmes and Watson when Holmes (in a rare moment of holding the Idiot Ball) experimented with the root to see if it's the culprit.
    • In "The Adventure of the Greek Interpreter", the baddies attempt to kill their victim with charcoal gas.

    Live-Action TV 
  • In an episode of Angel, an angry client tries to kill Gwen and Angel with a modified elevator and poison gas. Luckily, vampires don't need to breathe.
  • Arrow. In "Dark Waters", Damien Darhk tests his gas chamber with the help of a brainwashed HIVE minion, then puts several captured members of Team Arrow inside, making the minion's death entirely unnecessary. Fortunately the Black Canary turns up Just in Time to shatter the glass with her Canary Cry.
  • Batman (1966) had a cliffhanger where Batman and Robin were tied up in a room while the Penguin's mooks sucked all the air out using a "Giant Reversing Bellows".
  • In the Breaking Bad episode "Cornered", a bunch of Cartel hitmen kill two of Gus's guys by redirecting the exhaust fumes of the truck they were protecting into the storage compartment where they were camped out. Which, incidentally, is a method actually used by the Nazis before they switched to Zyklon-B.
  • Buffy the Vampire Slayer had Angel rescuing Giles, Willow, and Buffy from the high school basement, where they were locked in with the gas turned on by an angry invisible girl.
  • CSI: NY: The taxicab killer of season 4 turned his cab into a mobile one of these.
  • In Farscape the Scarrans use a chamber flooding with paralytic gas. On learning he's trapped in one John yells, "Staleek, this is very unoriginal!"
  • One stunt on Fear Factor involved enduring a sealed chamber that filled with CS gas longer than anyone else.
  • On The Ghost and Mrs. Muir, Captain Gregg (the eponymous ghost) died by accidentally doing this to himself. He accidentally kicked open the valve on the gas fire in the small room where he was sleeping and asphyxiated.
  • The Man in the High Castle: Laura and her children are killed in a gas chamber inside the Kenpeitai headquarters that's made to look like a suburban waiting room with Zyklon-B. The claim that the agent is 'odorless' is something of a simplification - the nerves are simply rendered incapable of conveying the information to the brain. Kido even mentions to Frank that they have made "improvements" to the Zyklon-B the Nazis used. Ironically, Kido himself ends up locked up in the same chamber by the resistance after the Japanese evacuation and resigns himself to his death, but since the gas canisters are empty he survives.
  • One episode of Midnight Caller had Jack Killian interviewing a condemned man before his execution via gas chamber.
  • One of the urban legends busted by Mythbusters involves a man who, after a particularly starchy dinner, falls asleep in a small unventilated room and asphyxiates on his own flatulence.
  • An episode of The Pretender had Jarod as a prison guard, trying to clear a man before he can be executed via gas chamber. He gets the real killer to talk by locking him in the gas chamber during a practice run, then releasing gas (it wasn't really poisonous, but the baddie didn't know that) until the guy confessed.
  • The Prisoner (1967) episode "The Girl Who Was Death" had a room filled with poison-releasing candles that would explode if extinguished. The Prisoner escaped - this trap, at least - by placing all of the candles against the outer door and blowing them out with bellows.
  • A Sherlock Holmes mystery ("The Case of the Exhumed Client", with Ronald Howard as Holmes; one of the many mysteries specially created for one of the many TV series) involved a person who died from a candle he didn't know was poisoned. Holmes flushed out the murderer by closing everyone in a small room and lighting the candle. The murderer, preferring a blown cover to death, broke the window.
  • In the Stargate SG-1 episode "Dominion," Daniel gets caught in a room that is accidentally being flooded with toxic gas. Despite trying to breathe through his clothing, he inhales the gas for several minutes before the leak is shut off, but he seems to suffer no side effects whatsoever.
  • In The X-Files, one Serial Killer is motivated to help Agent Scully by a harrowing Near-Death Experience he had while strapped into the gas chamber, awaiting execution: he saw the ghosts of his victims, silently waiting to usher him to Hell. When his stay of execution expires and he's sent to the gas chamber for real, he sees them again...

  • In the Vocaloid song "Prisoner", Len dies getting gassed after hitting his captors. His death was later confirmed in the related song Paper Plane.

  • In Dino Attack RPG, the entire XERRD Fortress became a facility-wide version of this trope once the Deadly Gas defense system was activated.

    Tabletop Games 
  • In the 1E AD&D module The Hidden Shrine of Tamoanchan, the entire dungeon is this trope, at least until the PCs manage to open up some blocked ventilation passages.

    Video Games 
  • In Apex Legends, Caustic can create improvised gas chambers by using his gas traps in enclosed rooms and corridors. Caustic mains have been known to use gas traps to block entrances to rooms full of enemies before following up with another gas trap or the Nox Gas Grenade.
  • Parodied in Barkley, Shut Up and Jam: Gaiden, where at one point your party is trapped inside a cabin which is slowly filled with sugar substancenote . The trap fails.
  • There are three rooms in Batman: Arkham Asylum that end up getting filled with Smilex, forcing Batman to find a way to activate the ventilation system to purge the gas.
  • In Batman: Arkham Origins, corrupt Police Commissioner Loeb is put into the gas chamber of Blackgate Penitentiary by Black Mask or rather, the Joker and executed, with Batman arriving just too late to save him.
  • At one point in BioShock, Andrew Ryan kills Julie Langford by sealing the door to her lab and flooding the room with poison.
  • In Child of Light's Final Dungeon, Nox locks Aurora in a hall flooded with green gas, which requires solving a switch puzzle to escape.
  • Call of Duty: Black Ops reveals during the mission "Project Nova" that Dragovich first tested out the chemical weapon Nova 6 by locking several of his own men inside a pair of sealed chambers and pumping the chemical inside them (one of them, anyway, before the British Commandos intervened).
  • Some hidden ladders in the NES Commando lead to "Gasrooms" where you have a short time limit to grenade the right wall and find the way back out, or get killed.
  • There's a whole level dedicated to this in Dead Space. Standing too close to one of the Wheezers for too long will cause Isaac to die. Also, Isaac sometimes has to go out into the vacuum of space.
  • In Dino Crisis there is a scientist trapped in a room filled with gas. You need to resolve a puzzle to neutralize the gas and open the door. If you're successful, the dying scientist gives you a key you need to advance. After that, if you search at his corpse, you find an extra key that you can use to get some goods. You can kill the scientist by accident, or on purpose, flooding the room with lethal gas, but doing that, you only get the first key. After getting the key, you get ambushed by a velociraptor. You must survive a button-mashing event to escape from the room, leaving the dinosaur trapped. After that, you can kill the raptor using the computer to fill the room again with gas, poisoning him.
  • Doom³: An entire level is made into one of these, and you have to find the ventilation switch.
    Dr. Betruger: There's nothing left for you but a slow death as your lungs fill with toxic gases.
  • In The Elder Scrolls IV: Oblivion, several Ayleid ruins contain an interesting variation on this: step into an empty portion of a large room, and walls will slam down, temporarily trapping you while the room is pumped with gas. There are also rooms that simply have vents that always emit toxic gas.
  • In the third Exmortis game, a lock puzzle on a door ends in a room that quickly fills with knockout gas, complete with someone maniacally laughing, rendering you unconscious for several days in a surreal dream sequence, conrolled by the Reader. Notes found when you recover state that said chamber was used as a "decoy entrance" for the resistance base you were trying to get into.
  • Fallout:
    • Fallout 2:
      • The game features a uranium mine in the town of Broken Hills that's temporarily shut down because it's filled with radon as a result of the air purifier breaking down. You can repair it, but you will take periodic damage when in the mine unless you wear Powered Armor (originally the game was supposed to feature a gas mask, but it was Dummied Out, some Game Mods restore it though).
      • The cut EPA facility was also going to feature rooms with Deadly Gas and the gas mask mentioned above would have been used to cross the room without taking damage.
    • One sidequest in Fallout 3's Point Lookout expansion pack leads you into a radioactive gas trap.
    • Fallout 4 has the Halluci Gen Inc. building, where VIPs were invited to demonstrations of the company's "products", only to be lethally gassed instead. The Sole Survivor can use the poison gas against the Gunners occupying the facility, but it will also quickly drain his/her HP unless equipped with a hazmat suit.
    • Fallout: New Vegas: Dead Money takes place in a ghost town covered in a toxic red gas cloud. On both normal and Hardcore modes, there are concentrated clouds that drain health rapidly, while on Hardcore, you slowly lose health throughout the general outdoor area.
  • Tifa of Final Fantasy VII gets tossed into a gas chamber for a public execution midway through the game, and has to pick up the conveniently dropped key to her shackles with her feet to escape. Unlike other segments in the game, there is no time limit on this sequence - no matter how long you struggle, Tifa cannot be killed.
  • In Gradius V, the first half of stage 6 has lots of this. You may shoot the Deadly Gas produced by them, before you getting into them and getting destroyed.
  • In The Journeyman Project, the NORAD VI installation is flooded with sleeping gas, requiring you to obtain an oxygen mask before you go there.
  • Knights of the Old Republic II features the Jekk'Jekk Tarr, a bar for aliens on Nar Shaddaa where the atmosphere is toxic to humans. It also had the HK-50 unit turn the entire dormitory section of the Peragus mining facility into one of these by sabotage. Both games let you use computer terminals to release poison gas on enemies as opposed to fighting them directly.
  • In KZ Manager you must send there your inmates so thet the "lesser races" be exterminated.
  • Metal Gear Solid does this for a few spots if you get caught and one room where it will happen as a part of a storyline. In each case, gas fills the room and you quickly lose oxygen, but having an O2 mask equipped will slow it down. In two of these cases, there is no way to escape, and in the first, you don't even have the O2 mask. There is one room where gas is already there and you're forced to go through. Said area also has electrified floors, just in case, apparently.
  • Metal Wolf Chaos turns the entire city of Chicago into one big Gas Chamber for our hero. He needs to destroy the antitoxin canisters and seal the generators before the toxin level reaches lethal levels.
  • Metroid:
    • In Metroid Prime's Phazon Mines, Samus is attacked by a group of Puffers in a ventilation shaft, and they fill the tunnel with lethal meta-viprium gas that can only be ventilated by a switch reached with the Power Bombs found later in the level.
    • In Metroid Prime 2: Echoes, the Federation Marines that Samus is supposed to check on set one up with a dispenser for industrial-grade pesticides against the local fauna. Unfortunately, a gate malfunctioned and three Marines ended up dying in the room. However, the toxic gas used is unable to harm Samus in her sealed suit.
  • Onimusha 3: Demon Siege had a gas chamber trap where you had to unlock the door by completing a "Simon says" minigame before you succumb to the fumes.
  • In the original Perfect Dark, you must flee a room flooded with nerve gas during your escape from Area 51.
  • Portal ends with GLaDOS attempting to flood the final battle area with a deadly neurotoxin after Chell destroys her morality core. She's quite nasty about it too, taunting Chell about her impending death from the deadly neurotoxin (along with jabs of a more personal nature.) Portal 2 reprises this in its ending, except this time it's Wheatley who's the final boss flooding the arena with neurotoxin.
  • [PROTOTYPE] has it in the form of Bloodtox, a gas harmless to anyone not infected by the virus. Alex, a man made up entirely of infected material, discovered this fact when it was announced to a room full of soldiers he had infiltrated, that they had been exposed to the gas for the last ten minutes. His disguise didn't last long.
  • Act 3 of Rainbow Six: Vegas 2 involves a group of hostages locked in a sports arena with a gas bomb; unfortunately, you arrive too late to save them.
  • Ratchet & Clank: Up Your Arsenal invokes this with an entire arena, requiring you to beat all the enemies before Ratchet succumbs. It's just sleeping gas, but it works by depleting your health bar.
  • The original Resident Evil had a couple of poison gas death traps that activated if you did a puzzle wrong. In Resident Evil – Code: Veronica, a gas leak blocks your progress, and you have to find a way to activate the ventilation system to clear it.
  • Rise of the Triad has a few levels with touchplates which when triggered flood the area with poisonous green gas. Hope you either found a gas mask before you triggered it or at least manage to find one before all your health is gone. One of the quit messages reads "Press Y to release the cyanide gas." and is accompanied by an appropriate sound effect.
  • Star Fox Adventures: At one point in Cape Claw, you enter a chamber where noxious gas is freed, and you have to push blocks around to cover the gas sources while an Oxygen Meter starts emptying. Doing this will not only free Fox, but also the imprisoned CloudRunner Queen.
  • The Suffering takes place in a haunted Maryland prison. One of the characters is the former executioner, Hermes T. Haight. Hermes enjoyed his work, and his favorite method of execution was the gas chamber. He altered the gas to retain its color and odor so that he could watch the prisoner's reactions as the chamber was flooded. Eventually, he became so obsessed with the gas, that he decided he needed to experience it for himself. In the game, Hermes returns as a gaseous ghost who's always breathing in his own fumes. Late in the game, he becomes a boss who tries to kill you with his gas, and you need to find ways to block the sources of it before taking care of him.
  • Tales of Zestiria has a part where you're trapped in a room in some ruins, and have to depend on Rose to open the way out, but she activates different traps instead. One of the traps causes smoke to fill the room, which gradually obscures your vision and eventually gives you a Non Standard Game Over unless you activate the right switches.
  • The video game adaptation of The Thing (2002) has a scene where the protagonist is lured into a room quickly being filled with poison gas. The message left on a computer screen in the room is a nice touch:
    Breathe deep, Blake. Breathe deep and die.
  • In Vampire: The Masquerade - Bloodlines, the Mandarin holds the player character in a sealed room and floods it with carbon monoxide, to absolutely no ill effect. It's not intended to kill the victim, but to demonstrate that they're not alive in the first place.

    Web Animation 
  • An improvised version is done in the Mastermind series. The Mastermind locks his minions in the same room as him and orders a burrito.

    Western Animation 

    Real Life 
  • Some programmes of The Holocaust implemented by government agencies of Nazi Germany:
    • Shower rooms in some German Asylums, sealed to make them airtight and piping in carbon monoxide produced as industrial byproducts, during the 1939-41 T-4 Involuntary Euthanasia programme for German citizens with congenital disabilities and mental illnesses. Organised through the Chancellory office.
    • Converted vans utilising carbon-monoxide exhaust at Riga and the Kulmhof (Polish: Chelmno nad Nerem, Chelmno-upon-Ner - to distinguish from another Chelmno less than 100 miles away) extermination facility and typical gas chambers using carbon monoxide-rich exhaust fumes from a large engine at Belzec, Treblinka and Sobibor death camps during the 1942-3 Operation Reinhard to dispose of the non-skilled Jews of Greater Germany and the Generalgouvernement (Poland). These were retired upon the successful completion of the programme. Organised by SSPFs (regional SS and Police Chiefs) on a district-by-district basis. Incidentally, Those Wacky Nazis got the gas van idea from the Soviet Union, where the NKVD used a similar method to execute dissidents during The Purge under Josef Stalin.
    • Two, and later four, faux 'shower rooms' were built at the Auschwitz-II/Birkenau extermination facility to dispose of "undesirables" rendered "unfit" by disease, overwork, and underfeeding while being rented out as slaves to various German companies responsible for their welfare. The gas the Nazis used was Zyklon-B, a cyanide-based pesticide that was made in the 20s, and was responsible for killing more than one million people there this way. The facilities were partially demolished during the second week of the Soviet Vistula-Oder Offensive of January 1945 and were discovered by Soviet forces on the 27th of January. In their haste to leave with the Fit-for-work inmates, the Security Police abandoned 1.2 million sets of clothing and 8 tons of human hair. Extermination facilities were built by the SS Main Construction Office and operated by the SS Concentration Camp Office.
  • In the United States, this was once a common method for executions, mostly in the West. It has since fallen out of favor and is currently allowed as an alternate method of execution in only six states. The last person to be executed by asphyxiation was German national Walter LeGrand in Arizona in 1999. The federal courts declared this method as unconstitutional "cruel and unusual punishment" unless chosen specifically by the inmate. Today, the executions are made with lethal injection. (In 2014, when prisons were faced with a shortage of sodium thiopental due to the EU export ban, several states attempted to revive the gas chamber. As of this writing, they've not succeeded.)
    • The latter as well as the former have shown up in fiction.
    • Most gas chamber executions in the US (194) have happened in California, the last being Robert Alton Harris in 1992. The gas chamber in San Quentin Prison, which is today used for lethal injections, had nicknames 'The Big Sleep,' 'The Time Machine.' 'The Little Green Room' and, nastiest of all, 'The Coughing Box.'
    • After many states have had trouble obtaining lethal injection drugs and European nations refusing to furnish said drugs, a handful of states have introduced the use of nitrogen asphyxiation as an execution method, with Oklahoma being the first to adopt it as their primary method in 2018. The argument for using this method includes the fact that it's already in use in a veterinary context to euthanize terminally ill pets, and that unlike the cyanide gas chamber or even lethal injection, it is far less likely to go horribly awry and is believed to be essentially painless.
  • Schrodinger's Cat is a thought experiment in quantum physics, that imagines a cat is locked in a box with a flask of poison gas, and a radiation detector that will break the flask if a radioactive atom emits a particle.
  • Finnish Army uses gas chambers to train the recruits to use gas masks. The recruits are taken to a sealed airtight building, the sergeant sets off a tear gas charge, and the recruits are to put on their gas masks. Nobody is allowed to enter out until the gas has dissipated.
  • Similar training had been performed in Eastern Bloc armies throughout the Cold War: a large field tent had been used for the chamber, the recruits inside were to put on their masks at the instructor's signal and at the same time the instructor would set off the tear gas charge. Things would go nasty if the filters on some masks had been previously damaged, which often happened. That's why a tent was used, to roll up the fabric sides and release quickly those unfortunate recruits to open air.
  • At US military basic training recruits must go through the "Confidence Chamber", where the recruit's division goes into a room, the instructor sets off a tear gas capsule and the recruit must take off their mask and recite whatever the instructor tells them to.
  • The US Air Force and US Army do this same thing as part of NBC training. They will only let you out of the chamber if you manage not to panic. The idea, of course, is to show you that A) Your chemical warfare gear will protect you if you are wearing it, and B) Show you why you want to make sure you wear it when needed.
  • There is also the need to be sure a future sailor or airman confronted with a messy, smoky, and incendiary malfunction of the ship or plane will stay calm and proceed to do the needed repairs instead of panicking.
  • Mandatory prep for a trip on NASA's Vomit Comet, the KC-135 weightlessness simulator, involves being put in a room that the oxygen is lowered in, then being required to remove your oxygen mask and answer math questions to see how your brain holds up. It's to help prepare people for what could happen if the thing loses pressure at 30k feet. It was even required for the cast of the movie Apollo 13 before their trips.
  • Herman Mudgett, better known as H. H. Holmes, was accused of having one of these built into his hotel in Chicago in the 1890s and killing numerous people there, giving him the dubious honor of being the first famous Serial Killer on American soil. The hysterical yellow press of the time claimed that dozens to hundreds were killed in his "Murder Castle", although later research showed that he "only" killed nine, mostly as part of an insurance fraud and due to several botched abortions. and his Murder Castle was simply a disused rooming house with nothing dangerous about it at all.
  • A common method of euthanizing animals in overcrowded animal shelters that lack the resources to give every animal a comfortable, humane standard of living. It's highly controversial, and there's pressure from animal rights activists to change the method to something else or remove the practice altogether. No-kill shelters have grown more common, though the regular kind remains.
  • Some people have also committed suicide this way, often using carbon monoxide. For example, Sylvia Plath infamously killed herself by putting her head in her oven with the gas turned on, and people have also poisoned themselves with carbon monoxide from a car engine in an enclosed garage. The good news is that this has been harder to do after household stoves switched from coal gas to natural gas and cars started installing catalytic converters to reduce emissions of carbon monoxide by converting it to carbon dioxide.