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Risk assessing products that contain small high-powered magnets

This guidance expands on a safety alert issued by the Office for Product Safety and Standards (OPSS) in May 2021 about products that contain small high-powered magnets. It provides additional context to support local authorities in carrying out risk assessments in relation to the ingestion hazard where two or more magnets attract each other across soft tissue.

When considering the harm posed by small high-powered magnets, the guidance nots that evidence suggests that internal injuries can occur when two or more magnets (or a magnet and ferromagnetic object such as a nickel disc) are ingested at slightly different times such that the two high strength magnets, although in different parts of the intestine, could attract each other, potentially resulting in severe injury such as the perforation of the intestine.

It is possible for all magnets (or a magnet and ferromagnetic object) whether weak or strong to attract each other. However, higher strength magnets are of greater concern because they will attract each other over longer distances and are more difficult to pull apart once in contact. In contrast, weaker strength magnets need to be closer to attract each other and are more easily pulled apart. Therefore, part of determining the risk requires measuring the magnetic flux density (the force that a magnet exerts over a given contact area) of a magnet, thereby providing an indication of the magnet strength or attractive force and the corresponding pressure that may be exerted by two magnets when they come into contact.

The British Standard EN 71-1:2014+A1:2018 Safety of Toys – Part 1: Mechanical and physical properties provides a definition of a sufficiently weak magnet for use in toys defined as a magnetic flux index below 50 kG2mm2. It is possible to still suffer harm in relation to ingesting two or more weak magnets with a flux of less than 50 kG2mm2, but the likelihood of the harm occurring is considered much lower by comparison with higher strength magnets.

In this guidance, OPSS defines high powered magnets as those which have a magnetic flux of greater than 50 kG2mm2. However, it is stressed that magnet strength should be considered along a continuum and is not a binary low-high categorisation.

The guidance document is available here.

A literature review of the harm associated with small magnet ingestions in both paediatric and mature consumer populations is also available; click here.

Office for Product Safety and Standards October 2021


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