According to a recent article by The Guardian, hazardous substances were found in all headphones tested by ToxFREE project. The investigation into headphones found that every single pair tested contained substances hazardous to human health, including chemicals that can cause cancer, neurodevelopmental problems and the feminisation of males. Researchers bought 81 pairs of in-ear and over-ear headphones, either on the market in the Czech Republic, Slovakia, Hungary, Slovenia and Austria, or from the online marketplaces Shein and Temu, and took them for laboratory analysis, testing for a range of harmful chemicals. Unfortunately, Fairbuds or the Fairbuds XL were not tested. However, seeing the results of these tests, it does make me wonder if there are (also) hazardous substances in Fairbuds or in Fairbuds-XL headphones.
The article by The Guardian can be found here and the full test results can be downloaded here (.pdf file)