Silicon zinc oxide (SiZn2O4)

Chemical: Silicic acid (H4SiO4), zinc salt (1:2)

Silicic acid (H4SiO4), zinc salt (1:2) is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Silicic acid (H4SiO4), zinc salt (1:2) are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Silicic acid (H4SiO4), zinc salt (1:2): Does not have an individual approval but may be used as a component in a product covered by a group standard. It is not approved for use as a chemical in its own right.

The Expert Panel for Cosmetic Ingredient Safety concluded that the following 24 silicate ingredients are safe in cosmetics in the present practices of use and concentration described in this safety assessment when formulated to be non-irritating, with the exception that the available data are insufficient to make a determination of safety for the use of naturally-sourced (i.e., mined) silicate ingredients in products that may be incidentally inhaled: Zinc Silicate.

Safe for use in cosmetics, with qualifications

Anaemia results from the excessive absorption of zinc suppressing copper and iron absorption, most likely through competitive binding of intestinal mucosal cells. Unbalanced levels of copper and zinc binding to Cu,Zn-superoxide dismutase has been linked to amyotrophic lateral sclerosis (ALS). Stomach acid dissolves metallic zinc to give corrosive zinc chloride, which can cause damage to the stomach lining. Metal fume fever is thought to be an immune response to inhaled zinc. (L48, L49, A49)

Ingestion of large doses of zinc causes stomach cramps, nausea, and vomiting. Acute inhalation of large amounts of zinc causes metal fume fever, which is characterized by chills, fever, headache, weakness, dryness of the nose and throat, chest pain, and coughing. Dermal contact with zinc results in skin irritation. (L49)

Zinc can enter the body through the lungs, skin, and gastrointestinal tract. Intestinal absorption of zinc is controlled by zinc carrier protein CRIP. Zinc also binds to metallothioneins, which help prevent absorption of excess zinc. Zinc is widely distributed and found in all tissues and tissues fluids, concentrating in the liver, gastrointestinal tract, kidney, skin, lung, brain, heart, and pancreas. In the bloodstream zinc is found bound to carbonic anhydrase in erythrocytes, as well as bound to albumin, _2-macroglobulin, and amino acids in the the plasma. Albumin and amino acid bound zinc can diffuse across tissue membranes. Zinc is excreted in the urine and faeces. (L49)

Non-metallic Mineral Product Manufacturing (includes clay, glass, cement, concrete, lime, gypsum, and other non-metallic mineral product manufacturing)

Silicic acid (H4SiO4), zinc salt (1:2): ACTIVE