A rapid response mechanism is a structured way for policymakers to request urgent, targeted evidence when an emerging chemical risk or policy question arises outside normal planning cycles. It helps ensure that scientific information can be mobilised quickly to support timely decisions. Within PARC, a Rapid Response Mechanism (RRM) has been set up to bring together expert knowledge at short notice and deliver rapid assessments or evidence summaries when new issues emerge, strengthening the link between science and policy on chemical risks.

In early 2024, PARC activated its Rapid Response Mechanism (RRM) for the second time following a sharp rise in the urinary levels of mono-n-hexyl phthalate (MnHexP) detected in kindergarten children in Germany, alongside findings in adults in Germany and Denmark. MnHexP is the main metabolite of di-n-hexyl phthalate (DnHexP), a phthalate regulated under REACH, and its occurrence in human urine is considered undesirable. The request submitted by the European Environment Agency (EEA) and the European Chemicals Agency (ECHA), aimed to better understand the extent of exposure to the European level and identify potential sources. 

In the months following the activation, investigations pointed out to a UV-filter used in sunscreens as the most probable contributor, with DnHexP (Di-n-hexyl phthalate) likely occurring as a contamination like the UV filter’s synthesis processes ↗. A study conducted on this basis found that half of all randomly sampled sunscreens using this UV-filter also contained DnHexP. This interpretation was further supported by a clear seasonal pattern (higher exposure in summer months), a strong statistical association with sunscreen use, and evidence that exposure to the UV filter can result in measurable MnHexP in urine. 

PARC partners are now building analytical capacity measure MnHexP and DnHexP in the upcoming PARC general survey and will also collect information on the presence of DnHexP in products. The newly generated European human biomonitoring and environmental data will provide a clearer picture of exposure levels across Europe, with results expected in 2028. 

This case illustrates the value of PARC’s RRM in delivering timely, policy-relevant scientific evidence to support regulators in addressing emerging chemical risks. More information on the RRM is available on the PARC website.