Are you a government official or similar authority who needs a quick, mundane excuse for a large number of mysterious, possibly supernatural deaths? Gas leaks are the way to go. They're accidental (no need to find a scapegoat!) and provide a good reason to keep people away from the site of the disaster (there might be lingering traces of gas there, after all!). You can even say that the gas was hallucinogenic, so that if any survivors or bystanders saw anything weird, well, that's why. And, as a very last resort, it leaves you with a plausible explanation for the whole site conveniently exploding.
The general populace will always swallow this one hook, line, and sinker, no matter how many times you use it or how implausible it is. Maybe people are more comfortable believing in gas leaks than in the supernatural. Watch out for nosy teenage detectives, though. Those are a bit harder to fool.
This excuse doesn't necessarily require there to be a victim; it can also be used to clear a given area so that no ordinary citizens get caught up in the supernatural or otherwise dangerous activity to begin with.
Please note that this trope applies to using gas leaks to cover up for other things, not covering up for gas leaks (unless an actual gas leak is being covered up by a story about another gas leak). If that's what you were looking for, we recommend blaming the dog. For cover-up excuses that don't involve gas leaks but are just as flimsy, see Extra-Strength Masquerade. Compare with Fiery Cover-Up. Conveniently Unverifiable Cover Story is related, though coming at it from a different direction.
- Hollow attacks in the first few episodes of Bleach were designated as such.
- In The Case Files of Yakushiji Ryoko, the destruction of a skyscraper in Ginza is attributed to a large-scale gas leak and explosion. In reality, the building's owner belonged to a cult that had bred a colossal snake and kept it near the top of the building. Inspector Yakushiji gave it a massive dose of growth drugs that caused it to instantly grow large enough to tear the building apart from the inside.
- Darker than Black:
- Early on, a Contractor completely loses control, causing a couple of massive explosions. This being the show that it is, the attempts to evacuate the area around the "gas leak" just made things worse, with the kid accidentally burning a friend to death who tried to get her to go to a shelter.
- In the second season, Genma gives an early hint of his craziness when, once he and his partner start attracting attention with an urban battle, he deliberately creates a gas explosion to give some Plausible Deniability. In a later episode, his boss makes an irritated reference to a supposed gas explosion in Russia rumored to be a massacre by Contractors.
- In Lycoris Recoil, incidents involving Lycoris are explained as some sort of accident. In the first episode, Takina ventilates a room of arms dealers in a high-rise building with a machine gun, but Saori, a civilian Takina later meets, only hears that a "gas explosion" had occurred.
- In Magical Record Lyrical Nanoha Force, the official records give a combination of earthquakes and poisonous fumes as the reason behind the complete destruction of Tohma's Doomed Hometown in the world of Vaizen. Considering how he actually saw the possible culprits, Tohma understandably questions the truth behind that statement.
- In Mobile Suit Zeta Gundam, the Titans' pumping of poison gas into a space colony, killing all the inhabitants, was covered up as a malfunction of the air recycling system.
- In Omamori Himari, the destruction caused by Kuesu and Shizuku's rooftop battle is officially explained as a gas line rupture. When learning about this on the news, Kuesu dryly comments that she didn't know that people installed gas lines on the top of buildings.
- Arkham Asylum: Living Hell: In the aftermath of a demonic invasion of the asylum, Dr. Arkham decides the only rational explanation is that Scarecrow dosed everyone with fear gas. As punishment, Crane gets a month in isolation.
- In Fables, the first time Briar Rose falls asleep in the series, the Fables cover it up as a gas leak.
- Godzilla: Rage Across Time: After the Mongol fleet was destroyed by Godzilla, the Shogun came up with the story of a typhoon to cover up his involvement.
- It's used on occasion in Hack/Slash to cover for Slasher activity.
- Dr. White uses it to cover for the destruction of a group that found out about Slashers in Tub Club.
- In a heroic example, the police use it to cover up for the events of Mind Killer.
- The Halo Graphic Novel: The UNSC initially tries to cover up the damage from the space battle over New Mombasa as being caused by a gas valve venting pressure.
- In PS238, when Suzie Fusion loses her temper and almost blasts a group of mean older girls, this is the excuse used to cover up the incident. In fact, the school turns out to have large quantities of empty pipes running around the entire campus. This is just so they can claim any one of them had burst to cover up things like the odd explosion, or people with radioactive superpowers (like Suzie) irradiating the playground.
- In The Transformers: More than Meets the Eye, the Cybertronian Senate seems to have been fond of the phrase "faulty energon line" when it comes to explaining away various arsons and bombings. It doesn't work in the long run, however; by the comic's present day, the Senate no longer exists.
- In DCU storyline Who is Superwoman?, the eponymous villain murders a witness who spotted her and Reactron by deliberately creating a gas explosion which burns down the victim's apartment so "her death looks accidental".
- Taken almost literally in The Powerpuff Girls story "Monkey Business". Mojo Jojo starts his own restaurant, which the girls find suspicious but they are proven wrong time and again. Townsville is enjoying Mojo's chili, but it causes everyone to fart which Blossom mistakes as a gas leak.
- In the chilean comic Zombies en la Moneda, after Santiago, the capital city, had to be evacuated due to a zombie attack, the government claims that the cause of such evacuation –and of all the deaths at the hands of the zombies- it was for a vague “sanitary emergency”. This trope is partly deconstructed as it is implied that the only reason this zombie apocalypse cover-up works is because ordinary people prefer to think it was all the fault of a disease and forget that the dead came back to life ( something that many people witnessed)
- In Calvin and Hobbes, when Calvin comes home from school after running out of his class, he tries to claim that the school let all of the children go home early because there was a gas leak and everyone was evacuated. His mother isn't fooled and calls the school.
- In The Horsewomen of Las Vegas, in the chapter that flashes back to when Charlotte Flair was a college medical student with plans of being something other than a crime boss, her father and his most trusted associates show her evidence that her best friend, Santana Garrett, and her fiancee, Shane Douglas, were undercover FBI agents. They then leave her alone with them and leave a gun behind for her to shoot them. Once the deed is done, Tully Blanchard says, "Now it's time to arrange that gas leak" as they prepare a Fiery Cover-Up.
- In Fate/Parallel Fantasia, gas leaks are used as the standard explanation for people falling unconscious due to being drained of prana, mostly by True Caster and True Rider.
- Used as a plot point in Fate/Stay Night: Ultimate Master. The Plumbers are Genre Savvy enough to suspect something and send Ben Tennyson to investigate, leading to the whole plot of the fic. A later chapter actually has Ben comment on how flimsy this excuse was.
- Subverted and mocked in Fate/Zero Sense: After the fight between Rider and Lancer was seen by whole areas of civilians in broad daylight, the cover-up used to calm down the population was to tell them that it was special effects used for a movie by James Cameron. Kariya's reaction is to point out that it's still a better excuse than gas leaks.
- The Beauty and the Beast fic “Kissed by a Rose” ends with the castle residents deciding to claim that Alexander/the Beast has been in isolation for the last few years because he was ill, during which he met and married Belle and they have decided to return to public life following the birth of their daughter Gwen. In reality Gwen is the daughter of Gaston after he raped Belle, but Lumiere, Cogsworth and Mrs Potts assure Belle that nobody in the household will reveal the truth after Belle saved them all, and it's noted that Gwen's parentage doesn't matter in terms of her inheriting the throne as the title would always go to the oldest male heir.
- 30 Minutes That Change The World discusses this while averting it, as the Dursleys are killed in a house fire caused by a literal gas leak. Aurors talk about the fact that gas leaks are often used as cover ups of Death Eater attacks, but this is shot down when it's revealed that the gas lines to a large portion of houses in the area are badly corroded, and the Dursleys were just unlucky enough to have been the first house to finally go up due to it.
- In Three Strikes. After the air battle with unknown fighters during a training flight, Perrault makes it clear to Bartlett and mostly to Genette that the loss of 16 airmen was the result of mid-air collisions, bird strikes and pilot error. Needless to say, no one on base is buying that cover story.
- Close Encounters of the Third Kind has the government clear everyone from the area around Devil's Tower, Wyoming (where the aliens are soon to show up) by claiming there was an accident involving a train carrying nerve gas.
- Fantastic Beasts and Where to Find Them demonstrates a Double Subversion of this trope. A cop tries to claim the destruction at Kowalski's apartment is the result of a gas leak, only for all the witnesses to berate him and point out the lack of gas's scent. One man steps up to say that they all saw a magical beast cause the destruction, but before he can, Newt casts a spell over all of the witnesses and they frantically claim in agreement that it was a gas leak that caused everything.
- Ghostbusters II contains three, and none of them work. When Egon and Peter hold down the fort over a hole they dug while Ray abseils down it into the river of pink slime, first Peter tries to convince the police that they're with ConEd; he then tries to convince them that they're with the phone company; finally, he pulls out the gas leak line. And then all of New York City goes into a blackout.
- In Godzilla (2014), the Janjira incident was caused by the male Muto burrowing into the plant's core and feeding off the radiation until it grew to maturity. The surrounding area wasn't evacuated due to radiation but to hide the existence of the Muto's cocoon.
- Hellboy II: The Golden Army: FBI Director Tom Manning tries to use a gas leak story to cover up the BPRD's investigation of Prince Nuala's massacre of an antiquities auction. Then Liz uses her pyrokinesis to set off the corresponding explosion — and Hellboy intentionally positions himself where he'll be blown out a window into the midst of Manning's crowd of reporters.
Hellboy: World, here I come.
- John Wick: Chapter 2: Jimmy the policeman takes one look at John's house, which is on fire from several grenades and says "Gas leak?" It's made clear in both movies that Jimmy knows exactly what John does for a living, and is willing to accept any semi-plausible excuse to keep the rest of the police from getting involved.
- Mars Needs Women. On being told that Mars Needs Women, the Secretary of State orders a press release declaring that the transmission was a "freakish malfunction of a highly sophisticated global communication system". Why he didn't just go with his first reaction—that it's a practical joke—is a mystery, as it would have sounded a lot more plausible. It's what the press believes anyway.
- The trope is exaggerated and Played for Laughs in the first Men in Black movie; as evidenced by the page quote, the typical cover story for UFO sightings given by MIB agents takes multiple elements from every standard, individual variant of the trope (swamp gas, weather balloons, Venus) and combines them into a single cover story. They do have the added benefit of a neuralyzer, which apparently makes its victims very impressionable while the agents work their cover story, and they'll even scorch some terrain as necessary with flamethrowers to make it more credible. The brain seems rather desperate to fill in gaps in memory. Agent J, for his part, hates how stupid and standard the cover stories are and makes it a point to come up with things that will make more sense and make the witness feel better about themselves (e.g. telling the bug man's wife that she left him because he was a Domestic Abuser, which was probably pretty close to the mark).
- In Mission: Impossible – Ghost Protocol, half the Kremlin blowing up is put down to gas lines exploding, and an unexploded nuclear warhead plunging down on San Francisco is a meteorite. When half the planet believes in conspiracy theories, why bother coming up with a plausible explanation as long as you can disavow it officially? Indeed, the way the civilian news reports are phrased indicates that pretty much no one believes the "accident with the gas mains" cover-up.
- In No Time to Die, Moneypenny informs M of the attack on Project Heracles, pointing out that the lab isn't on the books and telling him there were casualties. He says it was a gas leak. She asks if she should inform the Prime Minister.
M: It was a gas leak. I'll handle it.
- In Resident Evil: Apocalypse, to cover up the undead overrunning Raccoon City following the accidental release of the T-virus from a laboratory underneath the city streets, the Umbrella Corporation wipes out the undead and any potential witnessesto their corporate wrongdoing with a nuclear missile strike, blaming the destruction on a meltdown at a conveniently nearby nuclear power plant.
- Star Wars:
Darth Vader: The Senate has been informed that Jeddha has been destroyed in a mining disaster.
- Star Wars: A New Hope: Han Solo, answering the operator of a concerned nearby station following the dispatch of the Death Star detention block's guards and security cameras, attempts to buy time for Luke to find Princess Leia by claiming a "reactor leak" is in progress, asking for time to shut it down. It fails miserably.
- Rogue One: Darth Vader informs that this is how the premature Death Star test on Jeddha was covered up.
- Andor: Cassian’s true home of Kenari had a mining disaster to cover up something bad done there. Apparently, the Empire loves this excuse.
- In Tomorrow Never Dies, MI6 covers up the death of media mogul Elliot Carver at the hands of a '00' agent by issuing a press release reporting him lost at sea after falling overboard from his yacht in a suspected suicide, with the implication that this is not the first time they have done something like this.note
- Used in Transformers: Revenge of The Fallen — sort of, as it's the exact same excuse from Close Encounters:
Maj. Lennox: All right. China's cover story this time is "toxic spill"; they had to evac the area for Search and Rescue.
- In the Alex Rider book Eagle Strike, this is the official explanation for the attempt on Edward Pleasure's life.
- The Coldest War had some fun with this trope. British Intelligence knows a Soviet assassin with supernatural powers is planning to murder someone in their custody, so they evacuate the entire street to avoid witnesses and collateral damage using the gas leak excuse. When the assassin does show up, he's disguised as a National Gas repairman. When the entire house and half the street burn up thanks to the assassin Playing with Fire, the government has a ready-made explanation.
- In the Kim Newman Diogenes Club story "Moon Moon Moon", the area around a magical working is cordoned off by the police because of an "anthrax spill". Jeperson comments to his American counterpart that if every anthrax spill in Britain was genuine, the whole country would be awash with the stuff. She replies that her superiors prefer "experimental nerve gas" — unless it actually is experimental nerve gas, in which case they blame it on foot-and-mouth disease.
- This trope is used both literally and in the more general sense repeatedly in The Dresden Files novels as a theme illustrating the hapless nature of non-magical humans:
- One book lampshades and discusses it; Harry predicts that the latest bit of magical shenanigans will be explained by a gas leak, to which Billy retorts that subsequent inspection of the building will show that the gas pipes are intact, the gas company's monitoring instruments will detect no loss of pressure at the site, none of the victims will show symptoms of gas inhalation, and so on and so forth. Harry cuts him short by simply pointing out that nobody will want to admit that they have no idea what happened, so, to pacify the public and preserve their own jobs, they'll explain it away as a gas leak.
- This argument is reinforced by the fact that the experienced medical examiner Butters reported the discovery of "human-like, but definitely non-human" remains (actually Red Court vampires, which resemble human-sized bats) in a fire and immediately got suspended from work, given a forced psychiatric evaluation, and permanently landed with the worst assignments for having let the stresses of his job get to him and prevent him from recognizing what were obviously human remains that had been badly warped and distorted by the heat.
- In Fate/strange fake, the Snowfield authorities begin sweating bullets when they realize just how horrifically hard covering a Holy Grail War in their city is going to be, fully aware that the muggles aren't stupid and will begin digging. They manage to blame False Assassin's attack on terrorists, True Archer's attack on Gilgamesh a tornado, Gilgamesh and Enkidu's battle a gas leak... Even so, it's obvious The Masquerade is badly cracking by the time a lunatic in full golden armor takes responsibility for a massive magical blast that punches a hole in Snowfield's Opera House... on live television.
- Harry Potter:
- In Harry Potter and the Prisoner of Azkaban, the attack Sirius Black is accused of is described by Muggle authorities as a gas explosion. Of course, the latter may be a legit consequence of the former, because ordinary spells don't blow up the whole street.
- In Harry Potter and the Deathly Hallows, Voldemort's murder of a family of Muggles is attributed to a gas leak. Makes sense, as neither gas leaks nor Avada Kedavra leaves marks. But gas leaks also don't leave Dark Marks floating in the sky.
- Hive Mind (2016): The Liaison team specializes in these. To cover up the cracks in the False Utopia, incidents are blamed on accidents such as broken pipes or chemical spills; mysterious agents of other Hives are blamed if it clearly wasn't an accident. Only if there is no other alternative is an incident ever blamed on malicious actions by Hive citizens, because that would imply that the nosies missed somebody.
- In Honor Harrington, an "air car explosion" destroys the building containing the North Hollow Files, which were loaded with blackmail material to extort cooperation from others. In this case, nobody was really expected to buy it; the destruction of the site they were held at just had to be explained pro forma to match the Open Secret nature of the files themselves.
- In The Serpent's Shadow, the third book of The Kane Chronicles, it's mentioned that the accidental destruction often caused by the protagonists of the series is often blamed on gas explosions.
Carter Kane: The locals would just have to assume there was a gas explosion. We tended to cause a lot of those.
- Played with in The Long Dark Tea-Time of the Soul, in the aftermath of a mysterious explosion at Heathrow Airport:
"The usual people tried to claim responsibility. First the IRA, then the PLO and the Gas Board."
- In the second Montmorency novel, an explosive terrorist attack at a train station is covered up in this manner. The truth is never made public, and the repairman blamed for the faulty line hangs himself a year later.
- In The Rest Of Us Just Live Here the authorities claim that a teenage girl smoking near a gas leak caused the explosion at the amphitheater, rather than the Immortals invading.
- In Rivers of London, DI Nightingale has an arrangement with the Metropolitan Fire Brigade for when he has to Kill It with Fire. The fire brigade will have appliances on hand to make sure the blaze doesn't get out of hand, and the fire inspector will write the fire off as the result of "faulty wiring" or something similar.
- In Broken Homes, the near-total demolition of a small farm during a magical battle between two veteran combat wizards is written up as the result of some propane canisters exploding. As it happens, one such canister did blow up during the fight, but only accidentally and after the majority of the damage had already been done.
- In Wereling (2009), the final book has the villains teleport their magical tower into the middle of London, surrounded by a force field, and then start a Zombie Apocalypse. Afterwards, the story is that it was a gas attack by terrorists, which made people hallucinate a zombie apocalypse, while the force field was top secret technology that the British government used to contain the crisis. Aside from that ridiculousness, we never learn if the number of decapitated corpses made people question this story.
- In the first season, when Dr. Ferragamo's office is torched to cover up the evidence against Keith Palmer, the police initially report the possible cause of the fire as a suspected broken gas line.
- In 24: Live Another Day, a drone attack on a house that the CIA is investigating is covered up as being a gas main explosion.
- In the first episode of the second series of Being Human (UK), the villains use a gas leak excuse to clear out a whole neighborhood so they can use a psychic to find out which house the heroes (one of whom is a ghost) live in.
- In Season 3 of Black Lightning (2018), Freeland is the site of a war between the ASA and Markovia, with the entire area having been cordoned off and put under martial law, and a total blackout on information coming in or out. When the characters do manage to pick up an external news program, they're shocked to hear them talking about Freeland being under quarantine due to a SARS outbreak.
- In Buffy the Vampire Slayer, the government is fond of using explanations like this, usually involving gangs on PCP, but the only time the actual "gas leak" excuse is used, it's by the heroes. Sunnydale's Weirdness Censor being what it is, it's a completely implausible and unanimously accepted explanation for what happened.
- In an episode of Cold Case, a bomb was wired to a stove to make it look like the explosion was caused by a leaky gas pipe in the kitchen. The case is reopened years later when the new owners of the house find a piece of the detonator trapped behind a wall in the basement.
- Lampshaded in Community when, in the Season 5 "Repilot", the (ex-)study group explains their strange behavior in season 4 by saying there was a gas leak. In reality, showrunner Dan Harmon had been fired at the end of Season 3, and many fans of the show felt that Season 4 was subpar and out of character. Dan Harmon rejoined the show for the final two season (5 and 6). Jeff, however, tells the group, "Don't blame everything on the gas leak year," perhaps acknowledging that characterizations and plots were slipping towards caricature even before Season 4.
- Criminal Minds:
- One episode has a mundane variation: the heroes tell a civilian that her neighbor's house, which contains samples of anthrax he was planning on releasing as a gas, has asbestos.
- Another episode has a more conventional variety, as a trailer rigged to explode is labeled as a gas main explosion on the local news.
- In the CSI: NY episode "Snow Day", a criminal gang uses a fake gas leak to clear out the Crime Lab's building so they can recover the drugs that the police had confiscated (worth about a hundred million dollars).
- Subverted in Fringe. A gas explosion is the event; however, it's what caused said explosion that needs to be investigated.
- Haven: The Herald's editors Vince and Dave Teague use this excuse whenever the Troubles strike. They do it so often that Haven, Maine has got to be the leakiest town in America. It's a wonder anyone still lives there. This is lampshaded in one episode in which Haven becomes the target of two wannabe ghost hunters for a their web show.
Seth Byrne: How many gas leaks does a small fishing village need to have before they get new pipes?!
- Subverted in the Heroes episode "Tabula Rasa": Noah uses a carbon monoxide leak as a cover-up for Jeremy Greer, who accidentally killed his parents with his power. Nobody is fooled, and, in the end, a group of vengeful cops murders the kid.
- In the Monk episode "Mr. Monk Goes Back to School", Derek Philby gets rid of the school's groundskeeper by staging a gas explosion in his house: he makes a pinhole in the gas line so that fumes will come into the house, glues a matchbook to the bottom of a door with the ends facing down, and puts a piece of flint on the floor. The matches strike the flint when the door opens, blowing up the house. Monk determines that said explosion was staged because the weather was unusually warm on the night it happened (meaning the victim should not have had any reason to be trying to manually light the pilot light for the fireplace), and the air conditioning unit was on.
- Played completely straight in Oz. The fourth season ended with an explosion, caused by a home-made bomb created by one of the prisoners, destroying Emerald City. The opening of the fifth season showed the warden reopening the rebuilt prison, explaining the destruction as a gas leak. And everyone buys it. This in a prison that by then has had a major riot, a sexual harassment suit against one the head wardens, and quite a massive number of in-prison maiming and murders — all heavily covered by the media. The irony being that it really was a gas leak — the bomb never went off.
- The Professionals: In "Old Dog with New Tricks," the gas leak excuse is lampshaded by Crowley as to why the street outside a hostage situation is deserted. However, the goal is not to cover up what happened, but to remove witnesses to the ruthless (and illegal) tactics that CI5 will use to end the situation.
- Played with in Sherlock: an explosion is assumed to have been caused by a gas leak, but is then discovered to have in fact been a bombing.
- The Silent Sea: The Balhae Station moon base was supposedly abandoned and most of its crew killed by a radiation leak, but in reality the government had everyone killed to cover-up the experiments being done there.
- Stargate SG-1 played with this trope (as with so many others) over the seasons, coming up with mostly-plausible explanations for strange events on Earth. However, when an office building vanishes from downtown Seattle in a flash of light in one of the last seasons, the U.S. government desperately goes for the "gas explosion" explanation — an explosion that somehow resulted in no blast or debris of any kind. The media comments on this, but can't figure out what happened (after all, there's no reason to jump to "a human spaceship beamed it into space").
- Stranger Things:
- In season one, Hawkins Lab hide their involvement in the disappearance of Will Buyers and their own earlier attempt at covering up his death with a fake corpse, by making a deal with Hopper to pass the body off as that of some other boy who disappeared years prior, in exchange for him and Joyce going into the Upside Down to rescue Will.
- In season two, Nancy and Jonathan turn this against Hawkins Lab, as they attempt to use a recorded confession of the lab's part in the death of Barb Holland a year earlier. With the help of Murray Bauman, the two teens make up a story about a chemical leak from the Hawkins Lab being the culprit of Barb's death as to make the situation more believable, and thus expose the crimes of the lab without revealing the supernatural side of Hawkins.
- Season three ends with the deaths of thirty or so victims of the Mind Flayer being given a cover story that could only work in The '80s. According to the sensationalist news broadcast we see during the epilogue, they were all victims of a Satanic cult that was probably caused by Dungeons & Dragons, and was also probably behind Barb and Bob's deaths in prior seasons.
- Season four ends with a massive gate to the Upside Down opening underneath Hawkins, which causes massive damage to the town. The official story is that this was the result of a naturally-occurring 7.4 earthquake.
- In "Bugs", Dean attempts to use this to get a family out of their house so they'll be out of the way of a curse, but the father doesn't buy it — Dean's on the phone impersonating a gas company employee that they met earlier in the episode, and the father knows that employee's voice.
- Lampshaded in "Salvation" when the boys are trying to figure out how to get another family out of their house:
Sam: Maybe we could tell 'em there's a gas leak. Might get 'em out of the house for a few hours.
Dean: Yeah, and how many times has that actually worked for us?
Sam: Yeah. [thinks some more] We could always tell 'em the truth.
Dean and Sam: Nah.
- They pull the asbestos variation a few seasons later in "Family Remains" when they need to keep a family out of the house that they're moving into. A gas leak is mentioned, but the people they're talking to only really pay attention to the "asbestos" part. Unfortunately, the people moving into the house have someone who knows how to identify asbestos with them. He informs them that there's no asbestos in the walls and no gas leak, so they disregard what Sam and Dean said — including the truthful part that there's a health hazard to begin with — and all nearly die as a result.
- In "Back and to the Future", they manage to convince an entire town that there's a gas leak in order to evacuate it while they contain and deal with a whole mess of ghosts.
- In The Troop, the gym is destroyed by enormous worm monsters during a big dance. The Troop destroys the monsters and uses their miniature memory zapper monster (the snark) on everyone. As everyone surveys the wreckage, the Troop's adult advisor cheerily tells them that there had been a simple plumbing leak. In a later episode, they open a portal to a monster dimension and cover it with a tent and a gas leak sign. Unfortunately, the sign looks like one used by a band named "Gas Leak" and the heroes find themselves surrounded by fans who won't let anyone explain they're talking about an actual leak instead of the band.
- Played with on The Vampire Diaries: The Council are all killed in a gas explosion. The official explanation is that a gas pipe was busted and the house's owner failed to notice; however, the audience knows that the man actually disconnected the pipe himself and triggered the explosion in a strange murder-suicide.
- The first episode of Wiseguy has The Mafia doing this to get everyone out of a motel so that they could use it for an arms deal. Which is just as well, because everyone starts shooting at each other.
- The X-Files: In "Jose Chung's 'From Outer Space'", a Man in Black tries to persuade someone who saw a UFO into questioning his vision and perception and believing he only saw "the planet Venus".
"No other object has been misidentified as a flying saucer more often than the planet Venus."
"Even the former leader of your United States of America, James Earl Carter, Jr., thought he saw a UFO once, but it's been proven he only saw the planet Venus."
"If you tell anyone that you saw anything other than the planet Venus, you're a dead man!"
- In The Firesign Theater's Everything You Know Is Wrong!, Cox presents the audio from "the official stolen government training film of the secret plan to deal with an alien uprising." General Curtis Goatheart instructs troops to identify alleged sightings as:
"One! Pie plates, or as reflections in the atmosphere;
Two! Dry cleaning bags filled with marsh gas; or
Three! Mass insanity."
- In the Dark•Matter (1999) adventure "The Killing Jar", the bad guys use this modus operandi when killing more than two people. They call it "a tragic fire".
- In Mage: The Ascension, coincidental magic involved coming up with a plausible explanation for magic effects to avoid Paradox. One example given was justifying an explosion by saying it was a "natural gas explosion". This was a common tactic most of the supernatural conspiracies in the Old World of Darkness relied upon to uphold The Masquerade.
- 13 Sentinels: Aegis Rim uses this when Juro accidentally summons his Sentinel in the prologue. Similar cover-ups are used throughout the game for other Sentinel-related incidents, such as the fight between "Tomi" and "Erika" in the girl's bathroom being covered up as a fire inadvertently started by a smoking student.
- Assassin's Creed Origins states that Alan Rikkin's death in Assassin's Creed (2016) was purported to be a gas leak — a highly specific gas leak which killed one man in a packed room. Meanwhile, other Templar Isabel Ardant's death is blamed on some bad wiring at Buckingham Palace.
- In Nightbound, this is the explanation given for the Mardi Gras Incident at the end of the story when Thomas, turned into the Bloodwraith, goes on an unholy killing spree intent on killing not just the party, but the magical world. It's only if Alex has romanced Vera and goes with her to confront her mother, Lady Smoke, do they find she's the one who whipped up the story.
- In Five Nights at Freddy's: Sister Location, the grand opening of Circus Baby's Pizza World got canceled due to some "gas leaks" in the building. Actually, the actual cause was that William's daughter got killed by Baby.
- Resident Evil Village: After the events of Resident Evil 7, Chris and his team had the incident in Louisiana covered up by labeling it being caused by a toxic gas leak.
- Shin Megami Tensei games seem to love this trope a lot:
- In Shin Megami Tensei if..., a gas leak explosion is said to have been the cause of the huge crater were the school used to be in the endings of Shinji's and Akira's routes.
- In the "Golden UFO" case in Raidou Kuzunoha vs. King Abaddon, the dragon Kohryu tells Raidou to make up an excuse to cover up sightings of him, suggesting swamp gas as a possibility.
- In Persona 2 Eternal Punishment, the fire at the sanitarium is explained as a "gas explosion".
- In Devil Survivor, this is the excuse given for the Yamanote lockdown. Almost nobody buys it, at least for very long.
- Splinter Cell:
- The first game uses this to cover up the removal of a dirty bomb.
- Used in Conviction by Black Arrow to evacuate the Washington Monument fairgrounds so that their men can move in to get Sam.
- Used in Blacklist to cover up the vehicles Grim destroyed with a UAV in Tehran. Of course, a gas leak could destroy a dozen SUVs while leaving everything else around them okay, but the Iranian government goes along with it since they are no more eager than Fourth Echelon to engage in a shooting war with the U.S.
- World of Warcraft subverts this trope as a joke. Upon entering "Area 52", the player sees a flash of light and is given a tooltip that persists for 30 seconds which says, "The flash of light you did not see has erased the memories you did not have."
- The climax of Modern Warfare involves Zakhaev launching nuclear missiles at America/Western Europe, though you ultimately send abort codes. The game ends with a news reporter talking about "a series of nuclear missile tests in central Russia".
- Fate/stay night has a series "accidents" covering up mages stealing life energy from assorted Muggles and property destruction from Servant battles. The mass disappearances in the "Heaven's Feel" route are something the Church couldn't even try to cover up.
- Higurashi: When They Cry's "Hinamizawa Disaster" is said to be the result of a gas cloud erupting from the swamp, which has a grain of truth to it: gas was responsible, but it wasn't a natural occurrence or an accident. Gas-masked soldiers showed up in the town telling people to stay inside their houses due to poison gas, then murdered them by turning the houses into improvised Gas Chambers, killing nearly the entire town.
- El Goonish Shive uses this trope a lot.
- Take this one, for example:
Mr. Verres: Ah, some of my best work! Though I have been using that weather balloon excuse a lot. I think I'll blame swamp gas next time.
- This was apparently the official explanation for the events of Sister 2. While Mr Verres's cover-ups supposedly work regardless of how blatant they are, either he wasn't involved in this one, or Diane's deductive abilities are just that good, because she is very far from convinced.
- Take this one, for example:
- In Ow, my sanity, David knew that the dorm incident would be covered up by either arson or a gas leak. It was the latter.
- Skin Horse:
- One story arc of The Wotch involved a conspiracy of militant mind-controlling feminists with an Elaborate Underground Base below the school. After everything has been resolved, most of the mind-control victims have no memory of what transpired, and them waking up groggy in the school basement is explained with (what else?) a gas leak.
- SCP Foundation:
- Three hours after SCP-239 (a.k.a. "the Witch Child") was born, the hospital was destroyed by an explosion. The press was informed that the explosion was due to a gas leak.
- SCP-2602, which used to be a library, appears to be the subject of a particularly forceful and memetic one. It's clear that some serious stuff is going on there — torture devices, radiation, suspicious shrines, a toxic waste pit — but whatever anomalous effect its under forces people thinking about it to believe those things are either normal for a former library, or to creatively reinterpret them as library standards (e.g., the torture devices become "book binding machines" and the Cherenkov radiation becomes "Dewey radiation"). As noted in the report, this means that no one can ever refer to what was going on in the building between the time it ceased to be a library and when the Foundation found it — rendering the entire time Unpersoned.
- If I Am Ever Head of an Alien-Monitoring Agency on This Very Wiki recommends avoiding covering alien or paranormal activity this way, as it's a bright neon "something unusual happened here" sign to anyone even remotely Genre Savvy. Blame the damage on terrorism instead.
- Gravity Falls:
- In "Into the Bunker", Grunkle Stan claims that the damage caused to the Mystery Shack by an infestation of zombies was caused by "a big woodpecker". When the contractor doesn't seem to fall for that, Stan just straight-up bribes him.
- At the end of "A Tale of Two Stans", Grunkle Stan's long-lost brother manages to get The Men in Black out of town by claiming the energy caused by the Interdimensional Portal was actually from an unreported meteorite shower. It works because the agents just had their recent memories wiped.
- Played with in Justice League Unlimited: Lex Luthor secretly hacks into the Watchtower and fires its binary fusion generator at a Cadmus hideout, which is hidden beneath an abandoned warehouse in the middle of a town. The civilians don't know what happened and the League doesn't make a statement on it, but some assumed it was an industrial accident, while others saw a bright light in the sky and figured out it was from the Watchtower since the League had previously used their BFG on a previous mission, leading to the League getting hit hard with Hero with Bad Publicity.
- Metalocalypse: The Duncan Hills Coffee Company, eager to capitalize on a cross-promotion program with Dethklok, covers up a series of terrorist attacks on their stores by the Revengencers by repeatedly referring to them as "natural gas coincidence explosions".
- Inverted in an episode of The Simpsons, where a series of religious experiences turned out to all be caused by a dangerous gas leak that could've blown up and killed a lot of people had it not been detected.
- Superman: The Animated Series: In the episode "New Kids in Town", three members of the Legion of Super-Heroes travel back in time chasing after Brainiac who is trying to kill Superman when he was still a teenager in Smallville. At the end of the episode, Saturn Girl uses her Telepathy to erase the memories of all the locals who got involved or who witnessed anything, including Clark, and makes them believe that all the damage caused by the fighting was the result of a tornado.
- In the first episode of season one of X-Men: Evolution, after Scott Summers accidentally provokes a fire at a football game, Professor Xavier rewrites the memory of a nearby cop into thinking it was a leak in a propane tank.
- The official British government explanation for V-2 impacts was that the explosions were accidental and caused by leaking gas mains. Contrary to popular belief, they weren't trying to fool the British public, but rather the Germans, whom they were already feeding inaccurate impact reports. Incidentally, legend has it that one landed near a bar where the British Interplanetary Society were having a meeting, and they figured out what had really happened rather quickly.
- Paris Gun at the start of WWI led to an odd inversion. When the first shell impacted, Parisians thought that it was a gas main that had exploded, then, as more landed, that they were bombs from a zeppelin (as there was no engine noise). Eventually, it was realized that they were shells from a siege gun.
- The 1906 San Francisco Earthquake was another odd aversion. After the quake and ensuing fire, city officials blamed everything on a gas fire and ignored the part about the earthquake. Many cities had had great fires by this point, so it wasn't anything unusual, but earthquakes were incredibly freaky, and they didn't want to alarm the public.
- After the Trinity test of the first atomic bomb, officials released a cover story that a "remotely located ammunition magazine" had exploded. The cover story also mentioned "gas shells exploded by the blast" in case civilians needed to be evacuated away from the fallout.
- The whole "it was a weather balloon" excuse almost certainly comes from Project Mogul, which was testing the use of very large balloons for research and reconnaissance. Since it was a secret program, local authorities were often not in the know, and the lack of direct control over the balloons meant that there was a good chance they would fly over or crash near populated areas.
- This explanation was also attempted when the Japanese used the gulf stream to fly timed balloon-bombs over the continental USA. While these random and unaimed bombs very rarely came to earth in places where they could do any damage or indeed even be noticed, the US authorities tried to explain the explosions as accidents involving their own tech, rather than let it be known Japan was bombing the USA.