Are farts flammable
Executive summary
Farts can be flammable because some of the gases produced in the gut—most notably hydrogen, methane and hydrogen sulfide—burn in air when mixed with sufficient oxygen and exposed to a flame [1][2]. Whether any individual emission will ignite depends entirely on its chemical makeup and concentration; many farts contain too little flammable gas to sustain combustion, and attempting to light them carries real burn and fire risks [3][4].
1. Chemistry: What’s in a fart and what makes it combustible
Flatulence is a variable mixture of gases produced by digestion and swallowed air—primarily nitrogen, carbon dioxide, hydrogen, methane and small amounts of oxygen, plus foul-smelling compounds such as hydrogen sulfide; hydrogen, methane and hydrogen sulfide are combustible under the right conditions, which is why combustion of flatus is chemically plausible [2][1][5].
2. Variation matters: why some people’s farts ignite and others don’t
Gut microbial communities and diet determine proportions of flammable gases: bacterial fermentation can produce hydrogen in widely varying amounts (reports cite hydrogen from roughly 8% up to claims of 63% under some conditions), while methanogenic archaea convert hydrogen to methane in some people but not others, so only a subset of people produce enough flammable gas for ignition to be possible [6][2][7].
3. What ignition looks like and why flame color changes
Accounts and demonstrations describe blue or bluish flames when flatus ignites—consistent with hydrogen combustion—and yellows or oranges when soot or particulates are involved; hydrogen sulfide also burns, producing sulfur dioxide and water, which affects flame chemistry and byproducts [1][6].
4. Practical limits: why a fart isn’t a flamethrower
Even when combustible gases are present, the absolute volume of gas released in a single emission is tiny compared with engineered fuel sources; writers note one would need many emissions to equal even a small fuel tank, and most normal flatulence simply won’t sustain a long flame or generate a “flamethrower” effect [8][3].
5. Safety and documented harm: don’t try this at home
Multiple sources caution against experimenting: there are documented injuries and clear hazards—burns, ignition of nearby flammable materials, unpredictable fire behavior—and authorities and firefighter-oriented outlets explicitly advise against lighting farts because fires can spread and cause serious harm [4][3]. Popular science pieces and explainer journalism likewise warn it’s dangerous despite being technically possible [6][2].
6. Popular culture, demonstrations and the urge to sensationalize
The phenomenon shows up in cartoons and viral stunts and has spawned how‑to and curiosity pieces; some commercial or entertainment outlets amplify the spectacle without equal weight on safety, while scientific reporting (e.g., Chemistry World) places the chemistry front and center and notes public-health and diagnostic implications of gut-gas production—readers should note that sensational articles may overstate typical flammability or downplay risk [5][2].
7. Limits of the reporting and open questions
Available sources document the chemistry and many demonstrations but do not provide standardized measurements of how often a typical person’s flatulence reaches flammable thresholds nor detailed epidemiology of injuries; therefore, while the chemical basis and occasional ignition are well supported, precise frequencies and population-level risks remain underreported in the cited material [1][2][9].
8. Bottom line
Yes—flatulence can be flammable under the right chemical mix and oxygen exposure, but most emissions lack sufficient concentrations or volume of hydrogen or methane to ignite reliably; moreover, lighting farts is unsafe and has caused injuries, so the scientifically interesting fact should not be treated as a harmless party trick [1][6][4].