Silicon carbide

Endpoint summary

Description of key information

Silicon carbide is a chemically inert mineral substance. The determination of water solubility showed that silicon carbide “can be considered as practically insoluble in water” (see chapter 4.8), which is an indicator of a low bioavailability. The low bioavailability of silicon carbide was confirmed by a 10 days repeated dose inhalation toxicity test with silicon carbide (J Bruch et al. 1993; see chapter 7.5.3), in which this substance showed practically no lymphatic penetration. In addition, single dose toxicity studies by intratracheal instillations on silicon carbide with 3 to 12 months period observations (Bruch and Rehn, 1996; Bégin et al. 1989; Bruch et al. 1993; see chapters 7.2.2) also are suggestive of a the lack of adverse effects of silicon carbide in repeated dose toxicity test. This type of study (single dose administration) is used for drug regulatory purposes to observe the long-term effects of a substance.

In a cohort study (Edling, 1987; see chapter 7.10.2) more than 500 individuals exposed to silicon carbide working in the manufacture of abrasives were followed up from 1958 until 1983. The study revealed no significant increase in total mortality, cancer mortality, or incidence of non-malignant respiratory diseases ascribable to silicon carbide.

Against this background, based on the low bioavailability of silicon carbide and the lack of toxicological activity observed, we conclude that the substance has no adverse effects occurring as a result of repeated daily exposure during a prolonged period of time. A short-term repeated dose study confirmed this previous statement. Consequently tests on sub-chronic repeated dose toxicity of silicon carbide appear to be dispensable.