The Danish Environmental Protection Agency has completed its REACH substance evaluation of 4,4'-isopropylidenedi-2,6-xylol (EC No. 227-033-5, CAS No. 5613-46-7), commonly known as Tetramethyl Bisphenol A (TMBPA), confirming significant endocrine-disrupting properties for both human health and the environment.
Acting as the evaluating Member State Competent Authority (MSCA), Denmark reached its conclusion in July 2025, following assessment of in silico, in vitro, and in vivo data. The evaluation forms part of the 2024 Community Rolling Action Plan (CoRAP) under the EU REACH Regulation (EC) No 1907/2006.
Endocrine disruption confirmed; regulatory classification proposed
The evaluation confirmed that TMBPA meets the criteria for classification as an endocrine disruptor in Category 1 for both human health and the environment. Denmark plans to submit a harmonised classification and labelling (C&L) dossier in 2026.
While initial concerns also included reproductive toxicity, the evaluating MSCA determined that current evidence does not justify immediate regulatory action in this area. However, the observed endocrine activity—particularly anti-androgenic and estrogenic effects—triggers the need for harmonised classification under the CLP Regulation.
Once a harmonised classification is adopted, TMBPA may be considered for identification as a substance of very high concern (SVHC), marking the first step towards potential REACH authorisation or restriction.
Industrial uses and exposure profile
TMBPA is used primarily as a monomer in imported polymers and is registered in the EU at an annual volume of 1–10 tonnes. Its wide-dispersive use and potential for both environmental and worker exposure were key factors in its selection for evaluation.
Although the substance currently has no harmonised classification, self-classification by registrants already includes hazards such as skin and eye irritation and aquatic toxicity. The proposed classification for endocrine disruption will significantly increase regulatory obligations for manufacturers, importers, and downstream users.
Implications for industry and regulatory stakeholders
The confirmation of TMBPA’s endocrine-disrupting properties positions it alongside other high-profile bisphenols like BPA and BPB, which have faced escalating regulatory restrictions across Europe. Stakeholders in plastics, coatings, electronics, and polymer manufacturing should prepare for future classification and potential authorisation obligations.
Supply chain actors are advised to assess the presence of TMBPA in formulations and begin planning for substitution or reformulation if regulatory progression continues. Updates to safety data sheets and risk assessments should be anticipated ahead of the 2026 classification proposal.
