Small Parts
Many magnetic toys contain small magnetic parts that can come lose from the toy and which, therefore, the child potentially can swallow. While small, unsecured parts such as this are a hazard with any type of toy, in the case of magnetic toys reports suggest that children are more likely to swallow the magnetic components themselves than small parts of other toys.
Magnetic Rods
Another danger with magnetic toys is that some toys contain larger magnetic rods which would normally be outside the size range that one would expect a child to swallow. However, children do sometimes swallow the larger magnetic rods, with at least one parent reporting a child having swallowed as many as 20 magnetic rods in a single incident.
Shiny and Attractive to Children
While it is not entirely known why children more readily swallow the magnetic parts of these toys, and why they swallow larger parts than one would expect, some parents say the bright, shiny appearance of these parts and the way the balls are weighted makes them attractive to children. Post-incident statements made by children have identified that they perceived the parts in such terms as "looking yummy."
Magnets Attracted to Each Other Internally
A unique characteristic of magnetic parts in toys is that if a child swallows two or more of the magnets, the magnets can attract to each other internally. This can result in intestinal perforation, which can be fatal.
Possible Toxicity of the Materials of Which the Magnets are Made
A final factor is that the magnets may be made materials such as nickel-plating that may be toxic.