Toxicology and industrial hygiene
Synthetic amorphous silica are used in a variety of products and processes. Synthetic amorphous silica produces no acute toxic symptoms when administered either orally or dermally. Toxicity studies show that contact with synthetic amorphous silicia does not irritate either the eyes or the skin.
Chronic skin contact with synthetic amorphous silica is known to have the potential to cause drying or degenerative eczema. These reactions can be prevented by intensive protection or care of the skin. The data obtained from occupational medical examinations during decades of manufacture and use show no indication of sensitization potential. No cases of contact allergy were reported. Synthetic amorphous silica do not have a mutagenic effect. No effects due to treatment were established after repeated oral intake. No teratogenic effect was observed.
In inhalation studies, none of the examined synthetic amorphous silica led to durable changes in the lung or to progressive damage comparable to silicosis. Epidemiological studies on workers exposed to these substances in the long term showed no indications of silicosis.
The available data provide no indications of lung cancer or other long-term respiratory diseases.
Synthetic amorphous silica can be handled safely, given good industrial hygiene and provided that the applicable occupational exposure limits/threshold limit values are observed. In Germany, a workplace exposure limit (AGW) of 4 mg/m3 (inhalable dust fraction) must not be exceeded. The applicable occupational exposure limits in other countries can be taken from the safety data sheets. If these values cannot be ensured, local ventilation systems should be installed, or dust masks be worn.