STOT RE 1
Here is all you need to know about synthetic amorphous silica, the proposed classification of silica as STOT RE 1 in the European Union and Evonik’s position on this.
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CLH process update
You wonder why synthetic amorphous silica (SAS) has been subjected to a substance evaluation? Find more information about the CLH procedure and current status. More
After public consultation: majority of comments against classification of silica
The 60-day public consultation period within the current substance evaluation (CLH) process for synthetic amorphous silica (SAS) resulted in 71 comments from silica producers, trade associations, downstream users and authorities. A vast majority argued against the proposed classification of synthetic amorphous silica as STOT RE 1 within the European Union.
The dossier-submitting authority received 60 comments from EU member states, 8 comments from the United States and 3 from Japan. The commentators included prominent voices from the industry. In a total of 66 comments, they provided valid and well-founded arguments against the classification of synthetic amorphous silica.
The compiled comments and non-confidential attachments are also published on this ECHA website:https://echa.europa.eu/registry-of-clh-intentions-until-outcome/-/dislist/details/0b0236e1809d3513
After a thorough assessment of the relevant data and information, RAC forms its opinion on the proposed CLH. This opinion is expected within 18 months, approximately by November 2025.
Evonik’s position on the classification of silica as STOT RE 1
We reject a classification of synthetic amorphous silica (SAS) as STOT RE 1 because we are convinced that synthetic amorphous silica is safe for producers, processors and consumers. Furthermore, we are convinced that this hazard class for SAS is neither scientifically justified nor in terms of health policy.
The proposed STOT RE 1, H372 classification is based on inhalation tests that led to isolated cases of inflammatory processes in lung tissue. But the concentration and duration of exposure during these tests did not correspond to the real conditions when producing and processing SAS.
At no point in the value chain do people come into contact with dust of synthetic amorphous silica in hazardous concentrations.
Our main arguments against the classification of SAS:
- Synthetic amorphous silica is safe in compliance with the applicable occupational health and safety regulations – during production, processing, transport and storage. In the processed product, silica occurs in bound form only and is safe for consumers.
- In most downstream user sectors, there is no equivalent alternative to silica that offers the same level of quality and performance. This would invariably be a case of regrettable substitution.
- If processors were to dispense with silica, this would massively impair the quality and properties of countless high-tech and everyday products. Important EU export goods would no longer meet their previous quality standards and would be harder to sell globally. Some products could even disappear from the market.
The synthetic amorphous silica (SAS) types produced by Evonik are safe for everyone
involved in production, processing, transportation, and storage, as well as for consumers
of the end products.
At no point in the value chain do people come into contact with silica dust in hazardous concentrations. Evonik (including its predecessor companies) has been producing SAS since the 1940s. It is one of the most rigorously tested substances regarding potential risks to humans or the environment. Toxicological and ecotoxicological tests and decades of experience in its manufacture and use have resulted in no indications of risks to health or the environment through SAS when the substance is handled appropriately.
Silica is everywhere: Almost every industry – from consumer goods such as toothpaste to high-tech components including microchips – uses synthetic amorphous silica (SAS) as a process aid or functional additive. It is a versatile substance with a wealth of properties. In 95 percent of all applications, silica plays a key role in the function and/or properties of the end product.
In many applications, there are no equivalent alternatives, or developing substitutes and adapting formulations would involve considerable effort, resource consumption and costs. In many cases, SAS even fulfill several functions at once thanks to their versatile profile of properties: For example, adhesives achieve a firm bond, but do not drip or dry during processing. And in car tires, they increase driving safety, extend durability and reduce fuel consumption. In numerous applications, silicas contribute to sustainability by reducing the waste of resources or extending the service life of products.
Many everyday products, as well as future technologies, would function worse or not at all without silica. In technical terms, the replacement of a proven chemical with a non-equivalent substitute is referred to as a "regrettable substitution."
As a consequence, end consumers will receive products of a poorer quality, while important EU export goods will no longer meet their previous high quality standards and will be harder to sell globally. Some products could even disappear from the market.
FAQ: Silica and STOT RE 1
You have further questions regarding the CLH process, safety of synthetic amorphous silica and potential consequences of a classification?
Find answers in our FAQ section
Media Guide
Download our media guide containing Evonik’s positioning statement, background information on the CLH process, an overview of silica and its versatile applications, scientific studies and info graphics.
Do you have any further questions on silica? Then visit our comprehensive FAQ section with more than 40 answers, including scientific details for experts, on our Silica is Safe webpage