Chemical Exposure From Headphones: Should You Be Concerned?

People use headphones in many situations: at the gym, studying, running, walking, and reading. It is estimated that about 80% of young adults use headphones for music, averaging 0.5 to 2 hours daily. This may increase as the audiobook industry grows.

We often use them without considering possible health consequences, but new research warns that there may be risks. Here, we will look at a new study and consider whether we should reduce headphone use.

What does new research suggest?

Researchers purchased 81 pairs of in-ear and over-ear headphones available in Central Europe and from online marketplaces such as Shein and Temu. They decided to test 180 components, including soft and hard plastics and wires, to determine the presence of toxic chemical particles.

The results indicated that hazardous substances were detected in all tested products. Karolina Brabcova, a Chemical Expert at Arnika and a Project Researcher, warns that these chemicals may migrate from headphones into the human body.

She states, "Daily use — especially during exercise when heat and sweat are present — accelerates this migration directly to the skin." She further notes, "Although there is no immediate health risk, long-term exposures, particularly among vulnerable groups such as teenagers, are of great concern."

Which chemicals were found?

The study is concerned that manufacturers often switch from banned chemicals to substances that have the same negative health effects. Therefore, they tested these chemical groups:

• Bisphenols
• Phthalates
• Brominated flame retardants
• Organophosphate flame retardants
• Chlorinated paraffins

Bisphenols

Although there are many bisphenol types, the most common are bisphenol A (BPA) and its substitute bisphenol S (BPS). BPA is a synthetic chemical used to make epoxy resins and polycarbonate plastics found in products like food containers, water bottles, toys, and thermal paper.

A 2022 review states that BPA is shown to act as a hormone disruptor, which may lead to polycystic ovary syndrome, infertility in women, lower testosterone levels, and impaired fertility in men. Contact with BPA may also increase the risk of breast, prostate, ovarian, and uterine cancers.

As a result, manufacturers use BPS as a BPA-free alternative, but research suggests this substance is not entirely safe. A 2020 review warns that BPS is also shown to act as an endocrine-disrupting compound that may interfere with the hormone system.

BPA was found in 177 of 180 headphone samples, while BPS was found in 137 samples. In other words, all headphones had at least one of these toxic substances.

The study indicates the maximum concentration reached 351 mg/kg (159 mg/lbs), far above the 10 mg/kg (4.54 mg/lbs) limit proposed by the European Chemicals Agency. However, the U.S. does not have these regulations.

It only restricts daily intake from oral exposures, such as eating. While not a nationwide ban, under California’s Proposition 65, companies must label products if BPA levels exceed 1 mg/kg (0.45 mg/lb) due to potential reproductive toxicity.

Phthalates

About 60% of samples contained traces of phthalates. While most concentrations were low, a Temu sample tested at 4,950 mg/kg (2,245 mg/lbs) of Di(2-ethylhexyl) phthalate (DEHP).

DEHP is a liquid plasticizer used to make plastics flexible and is usually found in medical tubing, IV bags, and toys. A 2022 narrative review suggests DEHP may be linked to heart problems, liver damage, reproductive issues, and endocrine disorders. It also warns that exposure, even at low concentrations, may cause nerve damage.

Brominated and organophosphate flame retardants

Brominated flame retardants (BFRs) are added to plastics to reduce flammability. They are environmental pollutants and may disrupt thyroid hormone function, reproductive health, and development.

As a less dangerous alternative, manufacturers use organophosphate flame retardants (OPFRs). However, some studies state that exposure to OPFRs could trigger toxic responses, which may harm nervous, developmental, reproductive, endocrine, and respiratory systems.

Compared to BFRs, OPFRs were significantly higher in headphones: 72% of all samples contained five or more OPFRs, while 10% contained 10 or more. Two samples, Marshall Motif II ANC and Skullcandy Grom Kids Bluetooth, received negative ratings for exceeding the concentration limit of one of the OPFRs' chemicals.

Chlorinated paraffins

Chlorinated paraffins are used as plastic softeners. They are classified into short-, medium-, and long-chain forms.

Short-chain chlorinated paraffins (SCCPs) should have been eliminated under the Stockholm Convention in 2017 due to their toxicity. The U.S. Environmental Protection Agency (EPA) recognizes SCCP as a dangerous chemical that may lead to liver, thyroid, and kidney damage based on studies in rats. However, they are still detected in consumer products.

Because of that, the EPA strictly regulates its use, requiring companies to inform them 90 days before using this chemical. Under the EPA rule, importing products containing SCCPs is banned.

A headphone study also notes that although medium-chain paraffins are often marketed as a safer alternative to SCCPs, they share the same hazardous traits. According to them, most headphones contained levels below the recommended chlorinated paraffin threshold limit value.

Which headphones are safe to use?

The study based headphone risk assessment on how close each material is to the user and how likely chemicals may be absorbed through the skin. Exposure levels were divided into direct and indirect contact.

Direct contact includes parts that constantly touch the skin, such as ear tips, cushions, and the plastic housing against the ear. Indirect contact includes parts such as headbands, cables, and outer casings, which come into contact with the skin less often.

Chemicals were classified using a traffic light system. Green means the lowest risk because it meets the strictest safety standards. Yellow means moderate concern because the substance is legally allowed but may exceed limits. Red means serious concern because it exceeds legal limits or contains several hazardous substances.

The study tested 81 pairs of headphones. Because the list is long and detailed, we selected the most popular headphones and presented their overall rating. Use the following picture to identify the traffic light (green, yellow, red) rating for each headphone:

Final words: should you stop using headphones?

The answer is no. Research indicates there are no sudden health risks from headphones containing these chemicals. However, keep in mind that prolonged exposure may pose a risk.

That said, broader research is needed to evaluate potential harms. If you don’t want to risk it, the best choice is to buy headphones from the green-listed items, which meet the strictest safety standards. This way, you don’t have to worry if listening to music may affect your health.