A new European study has found that every headphone model tested contained chemicals linked to hormone disruption, reproductive harm, or other health concerns.
Researchers took apart each product and tested 180 plastic components, including ear cushions, headbands, cables, and internal housings.
According to the report, hazardous substances were detected in 100 percent of the products tested.
One of the most common chemicals found was bisphenol A (BPA), which has been widely studied for its ability to interfere with hormones. BPA was detected in 177 out of 180 samples. A similar chemical often used as a replacement, bisphenol S (BPS), was found in most of the remaining samples.
Bisphenols are commonly used in plastics and electronic components. The report notes that previous research has shown these chemicals can migrate from materials into sweat and be absorbed through the skin. Headphones, which sit directly against the ears for extended periods, enable prolonged skin contact.
Phthalates, chemicals used to make plastics flexible, were also widespread. All 98 soft plastic and cable samples tested for phthalates contained at least one type. In many cases, multiple phthalates were found in the same product. One children’s headphone purchased online contained 4,950 milligrams per kilogram of a phthalate known as DEHP, a substance restricted in many consumer products due to reproductive risks.
Flame retardants, which are added to plastics to reduce fire risk, were also commonly detected. While older types of flame retardants appeared mostly in low amounts, newer versions known as organophosphate flame retardants were found more frequently. In some products, researchers detected five or more different flame retardants in a single component.
Chlorinated paraffins, another group of industrial chemicals, were present in most samples, though none exceeded the European Union’s legal limit.
Researchers used a color-coded rating system to assess safety. The report shows 44 percent of headphones were rated “red,” meaning at least one component exceeded legal limits or contained multiple hazardous substances, while 42 percent received a “green” rating and 14 percent were classified as “yellow.”
The report emphasized that the study does not suggest headphones pose an immediate danger. However, researchers raise concerns about long-term exposure, especially because headphones are used daily by children, teenagers, and adults.
While individual chemical levels may be low, the study states that repeated exposure to mixtures of hormone-disrupting substances over time could present broader public health concerns.