Is silica safe?
The synthetic amorphous silica types produced by Evonik are safe – during production and processing and also for the consumers. Many years of experience and numerous studies support the statement that silica types from Evonik are safe.
However, the term “silica” is very broadly defined. Of course, there are some types of silica that could be dangerous depending on how they are used. For example, if it is breathed in, crystalline silica can harm your body.
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Synthetic amorphous silica (SAS) is used in many products and processes. There are no indications of any effects that could damage organs, tissues, or genetic material if SAS is breathed in once or repeatedly, even in high doses. No damaging effects on reproduction or development or damage to the immune or nerve system have been reported. As a result, no maximum amounts have been defined for the acceptable daily intake (ADI). SAS does not irritate eyes or skin. However, it is known that repeated skin contact during the production of SAS can cause dry skin and facilitate eczemas. These reactions can be prevented with skin care at the workplace. No such effects are to be expected through contact with silica in consumer products, as SAS is not present in a pure form here. Data from occupational medicine investigations over decades of producing and using SAS have shown absolutely no signs of allergy-triggering potential. Not a single case of contact allergy has been reported.
In inhalation studies on rats, SAS caused no long-term changes in the lung or progressive damage comparable to silicosis (Reuzel et al., Food Chem. Toxicol. (1991). This was recently confirmed in a renewed independent evaluation of older study data based on the standards at that time. In epidemiological studies on employees with long-term exposure, there were also no signs of silicosis; under realistic exposure conditions no damage is to be expected. The available data also contains no indications of lung cancer or other permanent respiratory diseases.
Synthetic amorphous silica can be handled safely when good occupational hygiene and the maximum allowable concentration are complied with. In Germany, currently (November 2017) a maximum allowable concentration (MAC) of 4 mg/m3 (respirable dust) must not be exceeded (other applicable guiding values at the workplace can be found in the respective safety data sheets). If this limit value cannot be guaranteed, local extraction equipment must be operated or dust masks must be worn.