Substances of Very High Concern

In 2018, ECHA determined that D4, D5, and D6 should be included on the Candidate List of Substances of Very High Concern (SVHC) according to the criteria set out in REACH as substances that are very persistent and very bioaccumulative (vPvB). It further concluded that D4 meets the criteria for persistent, bioaccumulative and toxic (PBT) substances, and that D5 and D6 meet the same criteria if they contain more than 0.1% of D4.

The silicones industry believes that in designating D4, D5, and D6 as SVHCs, ECHA did not consider the full range of relevant evidence that demonstrates these materials do not meet the criteria of vPvB and PBT substances. The REACH PBT/vPvB criteria were developed based on carbon-based organic chemical substances. However, siloxanes and silicones are silicon (Si)-based substances with an inorganic backbone, making them organic-inorganic hybrid substances, with physico-chemical properties very different from similar carbon-based substances. The criteria were not intended for inorganic substances and do not appropriately predict environmental behavior of hybrid organic-inorganic substances like the siloxanes.

In practice, the SVHC decision does not have any implications for the use of D4, D5, and D6. An SVHC listing is not a ban on the use of silicone polymers, nor is it a ban or a restriction on the use of D4, D5, and D6. Silicone polymers can be used safely in all products.

However, the formal identification of SVHC carries communication and risk management measure obligations. The complexity of this information varies according to the specific requirements of the supply chain. More information on these obligations can be found on the ECHA website.

The silicones industry is working closely and on an ongoing basis with the supply chain, the Commission, ECHA, and the authorities in European countries to encourage the use of updated PBT criteria and a weight-of-evidence approach for chemical assessments. The silicones industry strongly believes that the use of updated PBT criteria and a weight of evidence approach will provide the most accurate environmental assessments of D4, D5, and D6.


Learn about “Wash-Off” and “Leave-On” restrictions.

Draft Authorization Proposal

ECHA has identified D4, D5, and D6 in its draft recommendation as potential candidates for an authorization requirement.

Cosmetics and Siloxanes

Learn about Annex II of the EU Cosmetics Regulation.