Impact assessment

Request to inform the substance Risk Profile (Annex E of the Stockholm Convention)

Updated 4 December 2024

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 socio 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, as specified in Annex E (Information requirements for the Risk Profile) of the Stockholm Convention 

The POPs Review Committee (POPRC) has requested additional information relating to the adverse effects of polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), including mixed polybrominated/chlorinated dibenzo-p-dioxins and dibenzofurans (PBCDD/Fs), to inform the completion of a draft Risk Profile for these chemicals (as specified in Annex E of the Stockholm Convention). 

If the draft Risk Profile is agreed at the next POPRC meeting (October 2025) the proposal will move to the next stage: drafting of a Risk Management Evaluation (as specified in Annex F of the Stockholm Convention). There would then be a further request for information focussing on socio and economic impacts. However, we encourage stakeholders to share any such socioeconomic knowledge available at this earlier stage, (as specified in Annex F of the Stockholm Convention), in anticipation of POPRC call/s for information should the draft Risk Profile be agreed.  

For example, information on production, risk management measures, emissions, monitoring, alternatives, costs, impacts on society and proposed control measures in the use of PXDD/Fs along with justified requests for exemptions. 

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

Polyhalogenated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs) are a large group of chemicals containing one to eight 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.