Toxicology and industrial hygiene

Synthetic amorphous silica of type AEROSIL^® manufactured by flame hydrolysis is characterized by its amorphous structure. The determination method used on typical samples is enrichment of the crystalline fraction followed by X-ray diffraction. The detection limit of this method is less than 0.05 percent by weight. Under consideration of this detection limit Evonik silica are considered to be amorphous.

Synthetic amorphous silica is used in a wide variety of products and processes. The administration of synthetic amorphous silica results in no acute toxic symptoms when administered either orally or dermally. Studies for assessing toxicity with skin and eye contact show that synthetic amorphous silica does not irritate the eyes or skin.

It is known that synthetic amorphous silica can result in drying or degenerative eczema with chronic skin contact. These reactions can be avoided by intensive skin protection or care. The data from industrial medical research over decades of manufacture and use suggest no sensitizing potential. No cases of contact allergy have been reported. Synthetic amorphous silica have no mutagenic action. No teratogenic effects were observed. Following repeated oral administration, no treatment-induced effects were observed.

In inhalation studies, none of the investigated synthetically amorphous silica caused permanent changes in the lung or progressive injuries comparable to silicosis. In many epidemiological studies on chronically exposed workers, no indications of silicosis were found. Available data show no indication of lung cancer or other permanent respiratory ailments. According to all available data, synthetic amorphous silica are apparently not harmful to the health when applicable limits are observed.

In Germany, a workplace control parameter (MAK) of 4 mg/m³ (inhalable dust) may not be exceeded (country specific workplace control parameter are noted in our Safety Data Sheets for European countries). In case this cannot be assured local ventilation has to be realized or dust masks must be worn.