On June 3, the bodies of two college students were found in a giant helium balloon in Florida. The week before, a 10-year-old in New Jersey collapsed at a birthday party after sucking helium from a balloon. Is helium really that dangerous?
It can be. Breathing in pure helium deprives the body of oxygen, as if you were holding your breath. If you couldn't breathe at all, you'd start to die in minutes—as soon as your body exhausted the supply of oxygen stored in the blood. But helium speeds up this process: When the gas fills your lungs, it creates a diffusion gradient that washes out the oxygen. In other words, each breath of helium you take sucks more oxygen out of your system. After inhaling helium, the body's oxygen level can plummet to a hazardous level in a matter of seconds.
You don't have to worry about fatal asphyxiation if you're sucking from a helium balloon at a party. At worst you'll keep going until you get lightheaded and pass out—at which point you'll stop inhaling helium and your body's oxygen levels will return to normal. Of more concern is the possibility that you'll hurt yourself when you fall down. (The boy in New Jersey bumped his head and needed three stitches.) It's far more dangerous to suck helium out of a pressurized tank: If the gas comes in too quickly, your lungs might burst and hemorrhage.
Of course you're putting yourself in grave danger anytime you climb inside a giant helium balloon. The college kids in Florida weren't the first to attempt this stunt. In 2002, a case report from a Japanese medical journal described a similar episode: A drunken adolescent poked his head into an advertising balloon and asphyxiated. Several authors have also reported cases of suicide by helium inhalation.
Death by helium still seems to be quite rare. U.S. Poison Control Centers reported only two fatalities between 2000 and 2004. There's still an outcry from concerned parents whenever helium inhalation makes its way into popular culture. Federal Express had to pull a commercial that depicted the munchkins from The Wizard of Oz sucking balloons to keep their voices at a high pitch. Geoffrey, the Toys "R" Us giraffe, got a slap on the hoof for doing the same.
At the same time, doctors use a mixture of helium and oxygen (called "heliox") to help patients with upper-respiratory blockages. The treatment works because the helium is a very light gas, and it's easier to push it through an obstructed airway. (We get funny voices when we inhale helium because the lighter gas changes the resonant frequencies of our vocal tract. *)
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