Experts warn that these toxic compounds could leach out of the plastic and enter our bodies through the skin.

Scientists from the European ToxFree LIFE for All project tested commercially available headphones for 'endocrine–disrupting' chemicals.

These compounds include the so–called 'forever chemicals' bisphenol A (BPA) and the similar bisphenol S (BPS), which mimic the effects of the sex hormone oestrogen inside our bodies, leading to the early onset of puberty in girls, feminisation of males, and cancer.

Worryingly, despite well–reported biological effects, the researchers found that 'hazardous substances were detected in every product tested'.

So, are your favourite pair affected? Scroll down for the full list.  

Scientists purchased 81 pairs of in–ear and over–ear headphones, which were either available on the market in the Czech Republic, Slovakia, Hungary, Slovenia and Austria, or on the online marketplaces Shein and Temu.

BPA appeared in a staggering 98 per cent of headphones, while BPS was found in more than three quarters of samples tested.

In some headphones, concentrations were up to 315 mg/kg, which is well over the limit of 10 mg/kg suggested by the European Chemicals Agency.

Levels of bisphenols exceeding this limit were also found in the Sennheiser Accentum True Wireless, Bose QuietComfort Headphones and many others.

Alarmingly, previous studies have shown that BPA and BPS can leach out from synthetic plastic into sweat and be absorbed by the skin.

The researchers write: 'Given the prolonged skin contact associated with headphone use, dermal exposure represents a relevant pathway, and it is reasonable to assume that similar migration of BPA and its substitutes may occur from headphone components directly to the user’s skin.'

That is particularly bad news for in–ear sport headphones, such as the Samsung Galaxy Buds3 Pro, which had more than 10 mg/kg of bisphenols in some parts.

Karolina Brabcová, chemical expert at Arnika, which is part of the part of the ToxFree LIFE for All project, says: 'These chemicals are not just additives; they may be migrating from the headphones into our body.

'Daily use—especially during exercise when heat and sweat are present—accelerates this migration directly to the skin.

'Although there is no immediate health risk, the long–term exposures especially for vulnerable groups like teenagers is of great concern.'

The study found that high levels of BPA and BPS were often present in headphones directly marketed to children or teens.

The researchers suggest that small doses of these chemicals from individual sources may have a minimal effect.

However, when multiple chemicals from different sources combine to create a 'cocktail' effect, they could pose severe long–term health risks.

Besides these forever chemicals, some headphones also contained chemicals called phthalates, which are a class of reproductive toxins that can impair fertility.

The headphones were also found to contain chlorinated paraffins, which have been shown to cause liver and kidney damage.

However, these other chemicals were largely found in trace quantities.