Policy paper

Draft risk profile (covering Annex E of the Stockholm Convention)

Published 19 March 2025

The UK is a party to the UN Stockholm Convention on persistent organic pollutants (POPs), which are substances that persist in the environment, accumulate in living organisms and pose a risk to our health and the environment. They can be transported by air, water or migratory species across international borders, reaching regions where they have never been produced or used. 

Substances listed in the convention are generally prohibited from production, marketing or use, unless specific exemptions apply or acceptable purposes for continued use have been agreed. 

There is a process for parties to propose a substance for listing if they have gathered evidence that suggests it may be a POP. The POPs Review Committee (POPRC), the technical scientific committee of the Stockholm Convention, then considers and further develops the evidence that the substance demonstrates POP characteristics. 

If there is evidence that a substance demonstrates POP characteristics, the POPRC then considers the social and economic impacts of a ban or restriction of this substance and makes recommendations to the Stockholm Convention Conference of Parties, which is held every 2 years. 

Risk profile (covering Annex E of the Stockholm Convention) 

A draft risk profile has been published which further elaborates on, and evaluates, the information submitted in the original proposal that recommended polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), including mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBCDD/Fs) be listed as POPs. 

A risk profile sets out the evidence that these substances meet the criteria for a POP. We are interested in any information you have to support, expand or challenge the evidence provided. 

There will be an opportunity to provide social and economic information at a later stage in the listing process, but we would also be interested in any information on risk management measures, alternatives, costs, and benefits related to the use of these substances and justified requests for exemptions if no alternatives are available. 

Polyhalogenated dibenzo-p-dioxins and dibenzofurans (PXDD/F) 

Polyhalogenated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs) are a large group of chemicals containing 1 to 8 halogen atoms. The scope of the proposal covers polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs) and mixed polybrominated/chlorinated dibenzofurans (PBCDD/Fs). Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), though belonging to the group PXDD/Fs, are not included in the scope of the proposal as they are already listed in Annex C of the Stockholm Convention. 

There is currently no known intentional manufacture of PXDD/Fs, they are unintentionally generated through thermal processes involving brominated flame retardants (BFRs) including the uncontrolled burning of waste containing BFRs such as polybrominated diphenyl ethers (PBDEs). In addition, PXDD/Fs have been identified in emissions from metallurgical industries, thermal disposal of e-waste and mechanochemical non-combustion technologies being used to treat contaminated soil. 

Elevated levels of PXDD/Fs have been found in some children’s toys and consumer products sampled from around the world. There are links to elevated levels of PXDD/Fs in locally produced food, such as eggs, in areas with high levels of uncontrolled burning and dismantling or recycling of e-waste containing brominated or chlorinated flame retardants. 

It has been suggested that PXDD/Fs have the potential to damage human health and their high level of persistence in humans could lead to bioaccumulation.