Gas Leak Coverup

""The flash of light you saw in the sky was not a UFO. Swamp gas from a weather balloon was trapped in a thermal pocket and reflected the light from Venus. ""

- Agent K, Men in Black

""You know, just once, in ANYTHING, I'd like to see a gas leak actually just be a gas leak. It'd be so refreshing.""

- professor_prof, Fate/Stay Night Let's Play

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.

Worried that anyone with half a brain will see that this explanation doesn't quite add up? Don't be. 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 it's just that they're more comfortable believing in gas leaks than in demon attacks or the like). Watch out for nosy teenage detectives, though. Those are a bit harder to fool.

This excuse 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. 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 Coverup.

Anime and Manga

 * Fate/stay night has a series of such "accidents" to cover up a Servant stealing life energy from assorted Muggles.
 * Higurashi no Naku Koro ni's "Hinamizawa Disaster" is said to be a gas leak --
 * Hollow attacks in the first few episodes of Bleach were designated as such.
 * Early in Darker than Black, a Contractor completely lost control, causing a couple of massive explosions. This being the show 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, Gemna gives an early hint of his craziness by the fact that once he and his partner start attracting attention with an urban battle, he deliberately creates a gas explosion to give some Plausible Deniability, and 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 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.
 * The destruction caused by Kuesu and Shizuku's rooftop battle in Omamori Himari is officially explained as a gas line rupture. When learning about this on the news, Kuesu drily commented that she didn't know that people installed gas lines on the top of buildings.

Comic Books

 * 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 Fables, the first time Brair Rose falls asleep in the series, the Fables cover it up as a gas leak.

Film
"Maj. Lennox: All right. China's cover story this time is "Toxic Spill", they had to evac the area for Search and Rescue."
 * The trope is exaggerated and played for laughs in the first Men in Black movie; the typical cover story for UFO sightings given by MIB agents (quoted at the top of the page) mentions multiple elements from every standard, individual variant of the trope (swamp gas, weather balloons, Venus) and combines them into a single cover story. Though the MIB do put more effort into making it seem legitimate (such as having a crew of cleanup agents use flamethrowers to both burn away evidence of aliens and scorch some of the nearby terrain) and they have the added benefit of a memory-erasing device. The neuralizer goes a long way for justifying the whole ordeal: the brain will invent new memories to fill the gap, during which time it becomes very impressionable.
 * Close Encounters of the Third Kind has the government claiming a rail accident occurred with a train carrying nerve gas as a way to evacuate everyone from the area around Devil's Tower, Wyoming, where the Aliens are soon due to show up.
 * Used in Transformers 2: Rise of the Fallen. Sort of. Here, it's used in the same ways as in Close Encounters, right down to the excuse:


 * This was the excuse used in Hellboy II at the museum to keep people out while the team investigated.
 * Ghostbusters II contains three, and neither of them work. It's the scene where 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 Con Ed; 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 NYC goes into a blackout!
 * In The Living Daylights, assassin Necros uses this to cover up his attack on the Blayden safehouse, before throwing tear gas grenades hidden in milk bottles.

Literature

 * 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.
 * And 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 leave marks. But gas leaks do not leave Dark Marks....
 * In the second Montmorency novel, an explosive terrorist attack at a train station is covered up in this manner.
 * 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.
 * Honor Harrington: An “air car explosion” destroys the North Hollow files.
 * In the Kim Newman Diogenes Club story "Moon Moon Moon", the area around a magical working is cordened off by 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 is experimental nerve gas, in which case they blame it on foot-and-mouth disease.
 * In the Alex Rider book Eagle Strike, this is the explanation put out for the murder attempt on Edward Pleasure's life.

Live Action TV
"Sam: Maybe we could tell them there's a gas leak, that might get them out of the house for a few hours. Dean: Yeah, and how many times has that actually worked for us?"
 * 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.
 * Subverted in the Heroes episode "Tabula Rasa," Noah uses a carbon monoxide leak as a cover-up for Jeremy Greer who.
 * The government is fond of using explanations similar to this one in Buffy the Vampire Slayer, but the only time the "gas leak" excuse is used, it's done by the heroes.
 * In an early season one episode of Supernatural, Dean attempts to use this to get a family out of their house, but the father doesn't buy it. Lampshaded in the next-to-last episode of the same season, when the boys are trying to figure out how to get another family out of their house:

""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 first episode of the second series of Being Human (UK),.
 * The first episode of Wiseguy had The Mafia doing this because they wanted everyone out of a motel so they could use it for an arms deal. Which is just as well, because everyone started shooting at each other.
 * In the first season of 24, 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.
 * Subverted in Fringe where a gas explosion was the event, however it was what caused said explosion that needed to be investigated.
 * In the third episode of Sherlock, the "gas leak" excuse is used to cover up a series of bombings.
 * Mundane variation: In an episode of Criminal Minds, 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.
 * The X Files episode "Jose Chung's From Outer Space" features Jesse Ventura playing a Man in Black who tries to persuade someone who saw a UFO into questioning his vision and perception and believing he only saw "the planet Venus".
 * In the Monk episode "Mr. Monk Goes Back to School," a science professor kills his school's groundkeeper by puncturing a gas line, filling the house with fumes, and rigs the door to the living room with a matchbook, glued with the match heads pointing down, towards a scratch pad glued to the floor. When the groundskeeper comes home, he opens the door, the match heads strike the scratch pad, igniting the gas fumes and causing the house to explode.


 * On Nickelodeon's The Troop, the gym is destroyed by enormous worm monsters during a big dance. But 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 cherily tells them that there had been a simple plumbing leak.

Newspaper Comics

 * 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.

Tabletop Games

 * In White Wolf's Mage: The Ascension, coincidental magic involved coming up with a plausible explanation for magic effects to avoid Paradox. One example given was justifying a fireball/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.

Video Games

 * Splinter Cell uses this to cover up the removal of a dirty bomb.
 * Used again in Conviction by Black Arrow to evacuate the Washington Monument fairgrounds so that their men can move in to get Sam.
 * Shin Megami Tensei games seem to love this trope a lot:
 * 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 gases 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.
 * 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 and says 'The flash of light you did not see has erased the memories you did not have'.

Web Comics
"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."
 * El Goonish Shive uses this trope a lot. Take this one, for example:


 * 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... a gas leak, of course.
 * In Ow, My Sanity, David knew the dorm incident would be covered up with either arson or a gas leak. It was the latter.

Web Original

 * Three hours after her birth, the hospital SCP-239 (AKA "The Witch Child") was born in was destroyed by an explosion. The press was informed that the explosion was due to a gas leak.

Western Animation

 * On the pilot of X-Men: Evolution Scott Summers accidentally provokes a fire in a soccer game, Professor Xavier then rewrites the memory of a nearby cop into thinking it was a leaking in a propane can.

Real Life

 * The British Government explanation for V-2 impacts was the explosions were accidental ones caused by leaking Gas Mains. Gas explosions and the like were used in a misinformation campaign to lead the Germans to believe the V-2 rockets were landing short of their intended targets.