Magnets in novelty desktop toys are posing a growing and lethal threat to children, Toronto researchers are warning.

The newer, high-powered generation of magnets is 10 to 20 times strong than older magnets. Swallowing just one magnet is “generally innocuous.” But when more than one is ingested, they can link and anchor to one another across loops of bowel, twisting the intestine and potentially causing perforation of the gastrointestinal tract, researchers from Toronto’s Hospital for Sick Children write in this week’s issue of the Canadian Medical Association Journal.

According to data from the Public Health Agency of Canada, 328 children under 14 were seen in an emergency department between 1993 and 2007 because of an injury associated with magnets, the authors write. More than half — 178 — had swallowed the magnets.

In the United States, at least 480 cases of high-powered magnet ingestions have been reported over the past decade, according to the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition; 204 of those cases occurred in the past 12 months alone.

The majority occurred in children six and under. But teens are also inadvertently swallowing or inhaling magnets that are worn to mimic tongue, lip and nose piercings, the U.S. group reported last October.

The Toronto team says that, in the last year alone, Sick Kids surgeons were asked to see 13 children who swallowed magnets; four required surgery and long hospital stays. Most of the cases involve magnets sold in sets of 50 or 100 balls used to create different shapes. The kits aren’t marketed to children and are labelled to keep out of the hands of children.

“The issue is of course that desks are right at a small toddler’s reach and if they grab one or more and ingest more than one, that’s when issues come up,” says Dr. Daniel Rosenfield, a pediatric resident at the University of Toronto and Hospital for Sick Children. “The main idea is that once they’re out of the packaging and the label is off, kids are getting them. That’s the bottom line.”

“Modern magnet technology has transformed what was once an esoteric type of foreign-body ingestion into a common and lethal threat,” the authors write in the CMAJ.

“Small warning labels on magnet-based products are insufficient. Media exposure on the topic and information in primary care offices are needed.”

According to the researchers, older, ferrite magnets were “large and magnetically weak.” Newer, neodymium magnets have become “smaller, stronger and more prevalent.”

Signs that a child has swallowed a magnet include vomiting, abdominal pain and fever — symptoms so common in children that they can lead to serious delays in diagnosis, the doctors warn.

The Toronto team describes one case where a child who had “surreptitiously” swallowed a magnet underwent an MRI of his neck for an unrelated health problem. The child ended up with a perforated bowel.

Another three-year-old needed laparoscopic surgery to remove three neodymium magnets that had stuck together and eroded through two loops of the small intestine.

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