The type of silica used in cosmetics is called amorphous silica. There has been some confusion in the last few years over the safety of silica in cosmetics. Links between silica and the lung condition silicosis, cancer, and more recently, chronic kidney disease, are often referenced. What such articles, and those spreading this info, fail to realize is that the silica connected to such conditions is crystalline silica- completely different in chemical structure from the type used in cosmetics.
What's the difference? Well, simply put: in occupational environments where workers are regularly exposed to crystalline silica (such as mining, construction or sand blasting) the jagged structure of crystalline silica can embed itself in the lungs, creating scar tissue.
Since amorphous silica does not have the same jagged configuration, it does not cause this type of injury, nor is it known to cause cancer or accumulate in the body. The ingredient considered safe by all of the major governing bodies of the world, including the US Food & Drug Administration, Health Canada, the European Commission, and Japan's Ministry of Health, Labour and Welfare.