Source: Joe Keller / iMore

A coating used by battery companies to stop young children from swallowing lithium coin batteries could cause Apple’s AirTags to stop working, the company has warned.

Apple issued the warning in a support document put out a couple of weeks ago, as recently noted by The Loop.

The document is titled How to replace the battery in your AirTag and details the steps users must follow to replace the battery inside its new tracking device, steps that can also be found in our ‘How to replace an AirTag battery’ guide. AirTags use standard CR2032 batteries that you can buy basically anywhere, but the company says that certain batteries that use a bitterant coating might not work:

CR2032 batteries with bitterant coatings might not work with AirTag or other battery-powered products, depending on the alignment of the coating in relation to the battery contacts.

According to Duracell every year hundreds of lithium coin batteries are ingested by young children because of their small size. The company last year started applying Bitrex to its batteries to prevent this:

The battery has a ring-shaped layer which has a bad taste to discourage swallowing from babies and toddlers. We are using Bitrex®, the bitterest substance in the world commonly used in household products to prevent ingestion. The bitter taste layer on the Duracell cell is non-toxic and completely harmless if consumed.

The company does this because a swallowed battery can become a potentially fatal problem for young children, causing a harmful chemical reaction if it gets stuck in the esophagus. A neat safety measure, this does however mean these batteries aren’t suitable for use with AirTags, so make sure you check before buying!