The onions are caramelized in your pan, you flip them over with your black spatula, but in doing so you've probably laced your dish with hidden chemicals.
That's what a recent study published in the journal Chemosphere concludes — household black plastic items have been silently releasing harmful chemicals.
Researchers tested various household objects made from black plastic to see if they had traces of toxic substances usually found in recycled materials.
The study's lead author Megan Liu, a science and policy manager for US-based environmental advocacy organization Toxic-Free-Future, said 85% of the products tested contained chemicals used as flame retardants.
"We purchased 203 black plastic food serviceware items, hair accessories, kitchen utensils, and toys, and screened them for bromine, a chemical element that indicates presence of (the harmful) brominated flame retardants," Liu told DW.
"They then selected the 20 products with the highest levels of bromine, and found flame retardants in 17 of those products."
Why are black plastics harmful?
Plastics used in electronic and electrical products contain flame retardants to prevent them catching fire.
Decabromodiphenyl Ether (DecaBDE) was one of the most commonly used flame retardants until the European Union banned its use in electronics in 2006. Since then, similar chemicals have replaced it.
However obsolete additives like DecaBDE can slip through the cracks. When electronic plastics are recycled, these chemicals can make their way into household objects.
Recycled parts from old electronics like TV casings are often used to make black household plastics, but these recycled products are not strictly checked for the presence of harmful fire-retarding chemicals.
That's why Liu's team only tested black plastics for flame retardants and not other colored variants.
"We did not test other colors of plastic besides black plastic. Toxic flame retardants are intentionally added to the black plastic enclosures around electronics," Liu said.
Liu also found higher levels of toxic flame retardants in styrene-based plastics often used in electronics, including acrylonitrile butadiene styrene and high impact polystyrene (HIPS), "further supporting our hypothesis that flame retardants are ending up in everyday products we don’t expect".
What health risks do black plastics have?
Flame retardant plastics, particularly DecaBDE, have been linked to cancer, hormonal imbalance, nerve and reproductive damage. Potentially, it's a package of hidden health risks.
Similarly, another chemical compound called 2,4,6-Tribromophenol in black plastic is, "associated with thyroid disruption in humans and mice and has been detected in serum, breast milk, and placenta,” the study states.
Plasticizers all around
These flame retarding plastics have been known to leach from household electronics like televisions into the environment, according to 2015 research published in the journal Science of The Total Environment.
The consequences are greater when these contaminants travel from cooking utensils into food and from toys to saliva.
It's not just black plastic, though. In 2024, the Research Council of Norway identified a quarter of all plastic chemicals — not just those found in black recycled plastics — are hazardous to human health and the environment.
Is it time to throw your black plastic cooking utensils away?
In Liu's study, the highest leakage of harmful chemicals was observed in a sushi tray — a simple black takeaway box.
The study further observed high risk in kitchen utensils like peelers, spatulas and spoons.
Notable contamination was also found in children's toys, including plastic cars, a traveler's checker set and a pirate coin medallion.
Liu's team also expressed concern these fire retarding plastics were more often found in consumer products sold at small retailers catering to immigrant communities or specific ethnic groups.
But tracking contamination is difficult, particularly where recycled materials are involved.
Bethanie Carney Almroth, an ecotoxicology researcher at the University of Gothenburg in Sweden, said recycling programs like those used to recycle plastic drink bottles often mix waste products indiscriminately.
"We know very little about which chemicals are present in recycled materials," Carney Almroth told DW.
Households could address exposure to these chemicals by avoiding toys with black plastic components and replacing utensils made from these materials with wooden ones.
Other simple measures to reduce exposure include not reheating food in black plastic containers, and throwing away chipped or dented plastic utensils.
But Carney Almroth says such measures alone won't cut it.
"Heat and fatty substances like those found in food can increase migration of chemicals out of plastics, thereby increasing our potential exposures," said Almroth.
"Given the pervasive presence of plastics in products, and the lack of information available to the public, people should also support systemic changes necessary around plastics governance, including bans and restrictions on chemicals, changes in product design and shifts to reuse or refill systems," she said.
Edited by: Matthew Ward Agius
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Additional reading (opens in new window):
- Mass transfer of PBDEs from plastic TV casing to indoor dust via three migration pathways — A test chamber investigation
- State of the science on plastic chemicals - Identifying and addressing chemicals and polymers of concern