FAQ

Synthetic Amorphous Silica (SAS) is intentionally manufactured highly pure, crystalline-free, silicon dioxide (SiO2) and includes pyrogenic silica, precipitated silica, silica gel, and colloidal silica (generic CAS number 7631-86-9 (under which silicon dioxide/synthetic amorphous silica; EC#231-545-4, is REACH registered). SAS is a nanostructured material.  

Most commercial SAS products are white and fluffy powders, with the exception of colloidal silica which is usually produced as an aqueous dispersion. Most commercial SAS have average agglomerate sizes far above 100 µm.   

SAS is produced using long-established technologies and has been safely marketed for many decades with stable physical and chemical properties.  

AS as white dry powders or dispersions are used in a multitude of industrial and consumer applications. Some examples are given below: 

Some examples of SAS use which are essential for our well-being and enabling strategic autonomy of net zero and circular industries: 

• used as purification agent in the manufacturing of e.g., COVID-19 vaccines’ production; 

• as food additive to keep spices flowing; 

• in pharmaceuticals as tableting aid and to protect the active pharmaceutical ingredient from moisture  

• in toothpaste as abrasive agent helping with removal of plaque; 

• in animal feed for better digestibility of vitamins; 

• in polymers and rubber to reinforce and improve properties like dimensional stability and scratch resistance, SAS in rubber is a key element in “green” tyres, decreasing fuel consumption 

• In industrial liquid, gel and paste formulations such as coatings and adhesives to provide the ideal liquid flow or thickening behaviour, for example cartridge adhesives, automotive coatings, or superglue gels. 

• in electronics for chemical mechanical polishing (CMP) used for semi-conductors, in batteries used in electric vehicles (EV) and energy storage in general; 

• It is being increasingly used in diagnostic and biomedical research such as cancer therapy, DNA delivery, and enzyme immobilisation. 

• SAS has many other uses and benefits.

Synthetic Amorphous Silica (SAS) are produced by the members of ASASP in a total volume of about 840,000 tons per year. The European industry is a global leader in the production of SAS and a net exporter of SAS. The SAS industry is strategically important for the European market and the European SAS production represents a considerable portion globally (20% of the world’s production of SAS is originated from the EEA) second only to China. More information can be found in ASASP’s Socio-Economic Analysis of the Impacts of the Potential Classification of Synthetic Amorphous Silica (SAS) as STOT RE 1. 

SAS is safe.  

SAS is one of the most rigorously tested substances regarding potential hazards and risks to humans or the environment. Toxicological and ecotoxicological tests as well as epidemiological data in combination with decades of experience in its manufacture and use have resulted in no indications of risks to health or the environment through SAS exposure when the substance is handled appropriately. 

Regarding workplace health and safety, no respiratory diseases linked to SAS have been reported to health worker compensation insurance funds in Germany, where SAS has a long history of production. Rigorous occupational health and safety regulations ensure that silica dust is never present at hazardous concentrations during any stage of production or processing. Over 40 years of human health data supports this, showing no respiratory toxicity in humans. 

In July 2021, The Netherlands announced their intention to submit a proposal for harmonized classification under the Classification, Labelling and Packaging (CLP) Regulation (Regulation (EC) No 1272/2008). The Dutch National Institute for Public Health and the Environment (RIVM) proposes a harmonised classification (CLH) for untreated forms of Silicon Dioxide as STOT RE 1 (Specific Target Organ Toxicity – Repeated Exposure) by inhalation, (H372).  

On June 10, 2024, the public consultation for Silicon Dioxide was opened and closed on until 9th August 2024. Click here to visit the ECHA website for more information: Registry of CLH intentions until outcome – ECHA (europa.eu)  

SAS is safe in all its applications, and therefore untreated Silicon Dioxide (Synthetic Amorphous Silica, abbreviated as SAS) does not warrant a classification as STOT RE 1. 

SAS is being proposed for classification based on adaptive, unspecific inflammatory effects which are generic to all particles regardless of the substance. Classifying a substance based only on its particle effects deviates from the legal scope of the CLP because the hazard identification process can only assess the intrinsic properties of substances to determine its potential to cause harm.  

More than 90% of SAS forms, as placed on the market (as per Article 8(6) and 9(5) CLP, as supported by recital 30), are not respirable and therefore cannot cause any adverse effects to the lungs. Any concerns regarding inhalation exposure are thus mitigated, if not eliminated.  

You may consult our position paper here.