Titanium dioxide can form several different shapes, which have different properties. Some shapes can be converted to nanomaterials. Micronized TiO2 (also called “nano” or “nanoparticles”) was introduced in the early 1990s.Nanotechnology and micronization both refer to the practice of creating very small particles sizes of a given material. “Nanoparticles” usually refers to particles smaller than 100 nanometers; a nanometer is 1/1 billionth of a meter. At these small sizes, and at low concentrations, titanium dioxide appears transparent, allowing for effective sunscreens that do not appear white.

Lithopone was discovered in the 1870s by DuPont. It was manufactured by Krebs Pigments and Chemical Company and other companies.^[2] The material came in different seals, which varied in the content of zinc sulfide. Gold seal and Bronze seals contain 40-50% zinc sulfide, offering more hiding power and strength.^[3] Although its popularity peaked around 1920, approximately 223,352 tons were produced in 1990. It is mainly used in paints, putty, and in plastics.^[1]

We've used titanium dioxide safely for decades. However, recently its safety was called into question. 
 
At CRIS, we've explored the safety of titanium dioxide for nearly half a decade, including conducting double-blind research to test the safety of food-grade titanium dioxide (E171). Our study shows that when exposed to food-grade titanium dioxide in normal conditions, research animals did not experience adverse health outcomes.
 
It's important to emphasize that in a National Institutes of Health study, experimental animals were exposed to titanium dioxide in amounts as high as 5% of their diet for a lifetime and showed no evidence of adverse effects. 
 
A handful of studies greatly influenced the decisions made by the European Food Safety Authority (EFSA). Unfortunately, these studies did not consider that titanium dioxide exposure comes from food, not drinking water. Additionally, CRIS researchers could not reproduce the adverse outcomes identified by the studies through typical food ingestion. Regardless, the EFSA banned E171 as a food ingredient and for use in other capacities in the summer of 2022.
 
In 2022, the United States, United Kingdom, and Canada maintained that the scientific evidence supports that titanium dioxide (E171) is safe for humans to use and consume.

In food, titanium dioxide is often used as an artificial color additive. Tasha Stoiber, senior scientist at the consumer health nonprofit Environmental Working Group, says titanium dioxide can generally be thought of as a paint primer – it often goes on a hard-shelled candy like Skittles before the color is added to give it a uniform shine.

Less frequently, we ingest E171 through liquids such as salad dressing, dairy products, and some artificially colored drinks. However, since E171 is insoluble, manufacturers must use other stabilizers to keep E171 suspended in liquids as an emulsion; otherwise, it will settle to the bottom.