Sodium metasilicate is a member of the sodium compound family, according to the International Programme on Chemical Safety
Sodium metasilicate is a highly corrosive substance, particularly when water is added. For this reason, it is used in a variety of settings. The compound is found as an ingredient in fireproofing mixtures, household cleaning, insecticides, fungicides and as a bleaching aid. The United States Food and Drug Administration has approved one form of sodium metasilicate, the pentahydrate form, for use in washing vegetables and fruits.
Sodium metasilicate softens water and enhances cleaning performance and efficiency.
Because sodium metasilicate is a highly corrosive material, it can be highly irritating when it comes in contact with the skin, eyes or respiratory tract, according to the International Programme on Chemical Safety. If using as a cleaner, take precautions such as wearing a protective mask and gloves. If your skin does come in contact with the metasilicate, wash your skin and remove any clothing contaminated by the compound. If the compound comes in contact with your eyes, flush them thoroughly with saline solution.
None are recorded.
Source: LiveStrong, http://www.livestrong.com/article/274759-what-is-sodium-metasilicate/