On May 16th 2024, the European Commission (EC) took a decisive step to protect the environment by adopting a restriction on the use and marketing of three siloxanes:  

Octamethylcyclotetrasiloxane (D4),  

Decamethylcyclopentasiloxane (D5),  

and Dodecamethylcyclohexasiloxane (D6).  

These chemicals, commonly found in silicone rubbers, gels, solvents and resins, are integral to various industries including cosmetics, textile cleaning products, healthcare, and construction business.  

What’s new? 

Starting  June 6, 2026, the new restriction will prohibit the use or sale of these substances or mixtures containing these substances in any concentration equal to or greater than 0.1% by weight. However, derogation exists to allow for some deferred timelines for specific uses, stretching between 2027 and 2034:  

  • Cosmetic Products: non-wash-off cosmetic products must comply by 6 June 2027. 
  • Medical Devices: compliance required by 6 June 2031. 
  • Medicinal and Veterinary Products: compliance required by 6 June 2031. 
  • Dry Cleaning: The use of D5 as a solvent in dry cleaning is deferred until 6 June 2034. 

Exceptions are also in place for uses where D4, D5, and D6 are placed on the market for certain industrial uses, certain medical treatments, art restoration and lab reagents.  

 Path of Siloxane Restriction  

The EU has been at the forefront of regulatory authorities in the world to restrict Siloxanes. The identification of these chemicals as substances of very high concern (SVHCs) in 2018 due to their persistent, bioaccumulative, and toxic (PBT) properties, as well as their very persistent and very bioaccumulative (vPvB) properties, set the stage for these comprehensive measures. The restriction entered into force 20 days after its publication in the Official Journal of the EU. The EC emphasizes the necessity for industry stakeholders to take appropriate measures promptly to comply with the new requirements. 

Looking Ahead 

The EC started a draft proposal to nominate these substances as persistent organic pollutants (POPs) under the Stockholm Convention in 2020. A proposal has been commented on and is being reviewed by the Council. The US Environmental Protection Agency (EPA) began a TSCA risk evaluation for D4 in 2020 at the industry’s request, but this review is not expected to be completed soon due to a backlog of overdue evaluations. Meanwhile, individual US states like Washington and Vermont are considering their measures to regulate these substances.  

If You Are Impacted by the Restriction 

The EC’s restriction on D4, D5, and D6 marks a significant effort to mitigate environmental risks associated with these chemicals. To avoid incompliance, companies impacted by the restriction should check the use of siloxanes in their products and update their restricted substances lists and chemical policies in order to sufficiently communicate the risk and obligations to their suppliers.    

Published June 13, 2024

Text and image generated with the assistance of Artificial Intelligence