Siloxanes D4, D5, and D6 are known for their numerous useful material properties, which explains why they are commonly used in various everyday products. However, these chemicals also have harmful effects on both our health and the environment due to their toxicological and hazardous properties. As a result, Europe has complemented the existing REACH restriction to limit the use of these siloxanes into consumer products and reduce their release into the environment.
Utility and usage
Siloxanes in products have a wide variety of functions: as rubber, antifoams, gloss improvers, lubricants, softeners, anti-adhesion coatings and many more. In the cosmetic sector, siloxanes allow products to be spread out smoothly and uniformly, and their water-biding properties help to keep the skin hydrated.
Therefore, they are widely used in various industries and products, including dry cleaning products, anti-lice products, medical devices, cosmetics, cleaning of art and antiques, household care, and vehicle maintenance products...
| Siloxanes D4 (Octamethylcyclotetrasiloxane), D5 (decamethylcyclopentasiloxane), and D6 (dodecamethylcyclohexasiloxane) are monomers used in the production of silicone polymer. They can also be used as substances on their own or in the formulation of various mixtures that are subsequently used by consumers and professionals. |
What makes them dangerous?
D4, D5 and D6 are identified as substances of very high concern (SVHC) with very persistent and very bioaccumulative properties.
In other words, these chemicals are resistant to environmental degradation: they cannot be degraded by sunlight or destroyed through reactions with other environmental substances or transformed by ecosystem bacteria. Once they are released, they tend to persist in the environment and their emissions are not minimised through their life cycle. Moreover, when they evaporate in the air or dissolve in water they can migrate over long distances.
They can therefore cause serious damage to human beings and animals. These chemical substances accumulate in living organisms and might cause diseases when the concentration in the body becomes too high. They have a diverse array of adverse health and environmental effects. For instance, D4 has been classified as a substance very toxic to aquatic life with long lasting effects and is also suspected of damaging human fertility.
What do we do to protect the environment?
To address the risks to the environment, Europe restricted in 2018 the placing on the market of D4 and D5 in wash-off cosmetics, such as soaps, shampoos, hair conditioners,…. The cosmetic sector is the main target area as their products are responsible for the highest emissions of D4, D5 and D6 in the environment - 94% of the EU releases to the environment.
A new regulation was adopted on 16 May 2024 to further minimize the emissions of these chemicals. Siloxanes D4, D5 and D6 will now be restricted in cosmetics (both in wash-off and leave-on cosmetics) and shall no longer be allowed on the market. Besides, this restriction targets as well a range of other consumer and professional products.
The new restrictions will start applying after a 2-year transition period (starting on 6 June 2024), with longer periods for specific uses, such as:
- Medical devices and medicinal and veterinary products (7 years)
- Leave-on cosmetic products (3 years)
- The use of D5 as a solvent in the dry cleaning of textiles, leather and fur (10 years)
Derogations without a time limitation are nevertheless permitted for the placing on the market of those siloxanes for most of industrial uses, as well as for some professional uses (such as in medical devices for the treatment of scars and wounds). Additionally, some consumer silicone-based products containing D4, D5, D6 residues can still be placed on the market.
More information about the new restriction is available here.