Banned PBDE Flame Retardants Still Contaminate Europe

PBDE flame retardants remain widespread in Europe

A new study has found that toxic flame-retardant compounds banned two decades ago are still contaminating sediments and soils throughout Europe.

Scientists are especially concerned about how long these substances remain in food chains and indoor settings, where they can expose people.

These findings come from a systematic review recently published in Environmental Research.

The compounds involved are PBDEs, or polybrominated diphenyl ethers, once widely used because they retard flames.

They were incorporated into construction materials, electronics, cars, aircraft, furniture fabrics and padding - in effect, almost any product thought liable to catch fire.

Although effective in that role, evidence began emerging in the 1990s that they could build up in ecosystems and human bodies.

A Swedish study detected PBDEs in human breast milk, finding that concentrations rose sharply from 1972 to 1997. A US study published in 2002 identified still higher contamination levels in that country.

This is why they were prohibited in many regions of the world, including the US and Europe, during the early 2000s.

What we know about PBDE health effects

Yet, as with forever chemicals and microplastics, it remains hard to establish the precise health effects of PBDEs beyond their presence in people and the environment.

Much of the available evidence on their toxicity comes either from small laboratory animal experiments or observational research in human populations. Such studies can identify statistical associations, rather than prove causation.

Nevertheless, findings connecting PBDE exposure with liver, thyroid and breast cancer, as well as potentially reproductive health, prompted the European Union to start banning different forms of PBDE in 2004.

Scientists have now examined 181 peer-reviewed studies of PBDE contamination across Europe to assess the impact of those policies.

The picture was bleak: PBDEs continue to occur in European environments ranging from Spanish offices to isolated Alpine snow in Slovakia.

"Europe has made major progress in controlling PBDEs," says Khaled Abass, the review's lead author and an environmental toxicologist at the University of Sharjah in the UAE.

"However, the contamination record shows that past chemical decisions continue to shape present and future exposure. PBDEs are therefore not simply pollutants of the past. They are legacy chemicals with an active environmental presence."

PBDE contamination pathways and persistent sources

Levels outdoors were generally much lower than those indoors. As might be expected, the most heavily contaminated places were also those with the most intense industrial human activity: cities, factories and landfill sites.

BDE-209 was usually the predominant PBDE contaminant in sediment and wastewater sludge, whereas BDE-47 and BDE-99 were more prominent in air and soil.

Several studies included in the review indicated that PBDE concentrations in air and soil were falling, probably because of the bans.

The problem is not confined to Europe. A 2024 study detected PBDE in US fish, despite the compound having been banned there 20 years previously.

Older materials - including old furniture and technology - alongside recycled goods, waste flows such as human sewage and landfill, and contaminated sites such as former textile factories, fire-damaged land and scrapyards, are still releasing PBDEs into the environment.

"PBDEs move across connected systems: from products to dust, from dust to wastewater, from wastewater to sludge, from sludge to soils, and from sediments to aquatic food webs," Abass says.

He notes that PBDE exposure could remain a problem as more people embrace circular economies: purchasing and selling second-hand goods, recycling materials, repurposing waste - for example, as fertiliser - and renovating older homes.

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"Circularity without chemical safety can unintentionally recirculate legacy pollutants," he says.

"Materials once manufactured for fire safety may re-enter modern product chains through recycling if old chemical burdens are not carefully monitored."

The study appeared in Environmental Research.

This article was fact-checked and edited by Fiona MacDonald. Although we take pride in our process, we are only human. If you spot an error, please let us know.