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Teenage boys messing around with homemade blowguns are showing up in some emergency rooms after accidentally sucking the needle-tipped darts down their windpipes, doctors say.

No one knows how many mishaps may have occurred, but researchers at Nationwide Children’s Hospital in Columbus, Ohio, say they got worried after seeing three 14- and 15-year-olds in three months with the devices stuck in their throats.

“I find it concerning that this is becoming an emerging hazard,” said Dr. Kris Jatana, an expert in removing foreign bodies from airways. “Typically we see these aspiration events in children younger than 4.”

The problem seems to spring from a proliferation of more than 20 Internet sites that describe how to make the guns from household objects like sewing needles and shoelaces, said Jatana, writing in the latest issue of the journal Pediatrics.

He and his colleagues treated the teen boys who came to the ER in 2011 complaining of coughing and wheezing for hours. At first, they didn’t want to admit they’d been messing around with blowguns, or that they’d accidentally inhaled the homemade darts.

“One of the children was very reluctant and didn’t disclose until later in the evaluation when we showed the X-ray,” Jatana said.

When they did talk, the boys said the same thing: Using online instructions, they made blowguns out of household items like window shade wands, ink pen cases, shoelaces and straight pins.

When they took a deep breath to shoot the blowguns, they inadvertently sucked the darts into their throats. The trouble is, the act of inhaling opens the vocal cords, raising the risk that the objects will be sucked down more deeply, Jatana said.

“These three teenagers were very fortunate to have good outcomes,” said Jatana, noting the darts were removed with bronchoscopes. “But it is potentially a very serious problem.”

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The darts could have impaled the trachea or punctured the veins of the airways, he notes. They could have required open throat or chest surgery to remove.

A call to the American College of Emergency Physicians didn’t turn up concerns about the blowdarts, although a review of blowgun-related injuries in the Consumer Product Safety Commission’s database revealed at least two cases in the past five years.

There was a 9-year-old boy in December 2010 who swallowed a pin after inhaling a blow dart and a 14-year-old boy in June 2012 who did the same.

“I am certain there are more out there,” Jatara said.

It’s actually not that uncommon to swallow pins, needles or thumbtacks, Jatana said, because people often hold the objects in their mouths when their hands are busy and then accidentally inhale.

“I’ve taken those objects out of teenagers,” he said.

But he wants parents, doctors and teens themselves to be of the danger posed by blowguns, particularly when so many websites promote them.

“We’re obligated to educate the community on this type of hazard,” he said.

JoNel Aleccia is a senior health writer with NBC News. You can reach her on Twitter at @JoNel_Aleccia or send her an email.