EU sets regulations for D5, D6 cyclic silicones – what now?

As promised, on May 16, 2024, an amendment to Regulation (EC) No. 1907/2006 of the European Parliament on the Registration, Evaluation, Authorization and Restriction of Chemicals (REACH) was introduced to further limit the use of cyclic silicones in cosmetic products, according to the Official Journal of the European Union (EU).

See related: Statement on the Fragrance Makers Association Calling on Congress to Fund MoCRA Implementation

According to CosLaw.eu, the new restrictions are in addition to those currently set out in the REACH Regulation. The new regulations limit the use of decamethylcyclopentasiloxane (D5) and dodecamethylcyclohexasiloxane (D6) to a maximum concentration of 0.1% in both rinse-off and leave-on cosmetic products from June 6, 2027. The D5 restriction in rinse-off products applies from January 31, 2020; in particular, octamethylcyclotetrasiloxane (D4) was already banned under Annex II of the EU Cosmetics Regulation.

Persistent, bioaccumulative and toxic claims

The European Chemicals Agency (ECHA) sees this as a step in the right direction. In fact, ECHA initially proposed the restriction in January 2019, which was reportedly supported by 2020 opinions issued by the Scientific Committees on Risk Assessment and Socio-economic Analysis.

According to the agency’s proposal:

• Decamethylcyclopentasiloxane (D5) meets the criteria of Art. 57 letter d) Regulation (EC) 1907/2006 (REACH) as a persistent, bioaccumulative and toxic substance when it contains ≥ 0.1% w/w octamethylcyclotetrasiloxane (D4) (EC no.: 209-136-7); AND
• Dodecamethylcyclohexasiloxane (D6) meets the criteria of Art. 57 letter d) Regulation (EC) 1907/2006 (REACH) as a persistent, bioaccumulative and toxic substance when it contains ≥ 0.1% w/w octamethylcyclotetrasiloxane (D4) (EC no. .209-136-7). In addition to its specific properties, it also meets the criteria of Art. 57 letter e) Regulation (EC) No. 1907/2006 (REACH) as a very persistent and very bioaccumulative substance (vPvB) when it contains ≥ 0.1% w/w. in decamethylcyclopentasiloxane (D5) (EC no. 208-764-9) or ≥ 0.1% w/w octamethylcyclotetrasiloxane (D4) (EC no. 209-136-7).

In response to news of the change, ECHA said in a bulletin: “This measure will protect our environment by reducing emissions of these very persistent and bioaccumulative substances by up to 90%.

The impact of the cosmetics industry

To comply with the restrictions, cosmetic formulators are stuck between a rock and a hard place. As the Cosmetics, Toiletries and Perfumery Association (CTPA) explained in a statement, “D5 and D6 are very important ingredients in a wide range of cosmetic products due to their unique set of properties that cannot be fully replicated with alternative ingredients. Substituting their ingredients will reduce the product’s performance and, in some cases, its availability, without benefiting the environment.”

What’s more, color cosmetics expert Jane Hollenberg from JCH Consulting wrote in her latest article Cosmetics and toiletries article that a virtual ban on the use of cyclic silicones will have a dramatic impact on the color makeup segment, as these materials significantly impact the aesthetics and performance of color cosmetics.

“In terms of reformulation, there are no 1:1 replacements for cyclic silicones,” she explained. “And because they are not just a single formula ingredient, but also a solvent or carrier for many other ingredients, their upcoming ban will impact the choice of many ingredients. Not only must a formulator using cyclic products select a replacement solvent as the vehicle in the formulation, suppliers of many emulsifiers, film formers, texturizers and thickeners sold as dispersions or solutions in cyclic silicones must find suitable alternatives.”

The CTPA further expresses that existing restrictions placed on these materials have already reduced their presence in the form of washable products in wastewater and aquatic environments and volatile emissions from leave-on products. “The results show that wastewater emissions from leave-on cosmetic products are significantly lower than those from wash-off products due to the evaporation of D5 from the products while they remain on the skin or hair,” the agency said in a statement. “Therefore, the already published restriction of D4 and D5 in washable products is the most appropriate risk management measure.”

According to a recent opinion piece by David Clement in the Financial Post, “economic chaos” was predicted if the EU introduced a ban on these key silicone ingredients. His concerns extended beyond cosmetics to broader markets. “Without these silicones, it would be very difficult to produce semiconductors, and massive shortages would mean higher prices and lower quality for consumers.” He added that this does not include commodity markets where chips are an input, which means everything from cars to computers to consumer electronics. The total cost of the impact is so large and complex that it is difficult to estimate.”

He further added: “Even economic chaos might be worth it if these substances were actually so harmful that they deserved to be added to the list. However, the EU is the only entity in the world that has classified them as POPs (persistent organic pollutants) and restricted the use of siloxanes in trade. The (Canadian) government investigated them and came to different conclusions.

Contradictory findings

As Clement mentioned, Hollenberg highlighted how the US Environmental Protection Agency (EPA) and Health Canada have reached conclusions that conflict with the EU proposal on the environmental and toxicological properties of cyclic silicones. “The EPA has concluded that decamethylcyclopentasiloxane does not bioaccumulate through dermal evaporation and exhalation and does not pose an environmental hazard.”

According to Health Canada, because cyclic silicones are volatile, they are released into the atmosphere, where they decompose – first into silanols, then into carbon dioxide, water and silicon dioxide (silica). Therefore, “these products do not pose a risk to the environment.”

Additionally, the amount that volatilizes and decomposes in the atmosphere is equal to new emissions, as confirmed by a measured constant amount in the environment, so Health Canada says the material is persistent but non-accumulating. Therefore, the material was deemed harmless to human health and the environment.

“EU and UK cosmetics regulations are risk-based,” wrote Dr. Emma Meredith, CTPA’s chief science officer, in a 2021 report. Cosmetics and toiletries column. “Cosmetic products and their ingredients undergo rigorous risk assessment to ensure they are safe to use. (For example) the proposed actions on microplastics and CSS (EU Chemicals Sustainable Development Strategy) are driven by the threat. This is a disturbing trend that will impact the industry in the future and ultimately consumers. While maintaining a robust, long-term process for managing the chemicals we use in everyday products is essential, it is important that such a strategy is rooted in thorough analysis. scientific knowledge and that it assesses the key risks that need to be addressed.”

What can the industry do?

What can formulators and the industry do now that these measures are in place? “The replacement of cyclic silicones… (has) been the subject of much cosmetic formulation research and development and many related research and development activities, both in the short and long term,” Hollenberg wrote. “Formulation chemists hope for some relief as new chemicals and processes are developed – with requirements for long-term human and environmental safety more clearly codified in the EU.”

“D5 and D6 are used in a variety of leave-in cosmetic products, especially skin care products, leave-in hair care products and deodorants,” CTPA said. “The replacement of D5 and D6 in different types of personal care products must be considered on a case-by-case basis and requires a new formulation approach together with the creation of a new product architecture to achieve a product (that) matches the desired performance properties and sensory benefits of the specific original siloxane-containing final product , which constitutes a fundamental change in composition.”

This won’t be a small task. However, facing regulatory sand traps is simply par for the course for our industry.