Although barium sulfate is almost completely inert, zinc sulfide degrades upon exposure to UV light, leading to darkening of the pigment. The severity of this UV reaction is dependent on a combination of two factors; how much zinc sulfide makes up the pigments formulation, and its total accumulated UV exposure. Depending on these factors the pigment itself can vary in shade over time, ranging from pure white all the way to grey or even black. To suppress this effect, a dopant may be used, such as a small amount of cobalt salts, which would be added to the formulation. This process creates cobalt-doped zinc sulfide. The cobalt salts help to stabilize zinc sulfide so it will not have as severe a reaction to UV exposure.

Among the raw materials for coating production, titanium dioxide is more ideal, followed by lithopone. The covering power of lithopone is only that of titanium dioxide, and the price of lithopone is much lower than that of titanium dioxide, so lithopone still occupies a large market share.

Manufacturers get titanium dioxide from minerals called brookite, rutile, and anatase. It's processed into a powder and refined to meet strict safety guidelines.

China’s TiO2 exports were booming in 2016. The continuously depreciating RMB and the increasing export scales of China’s manufacturers have strengthened this development throughout the year. As a fact, many of China’s producers exported their products with a lower price while achieving higher profit margins in the domestic market of TiO2. Tranalysis, a trade analysis provider, now reveals the top 10 Chinese TiO2 exporters of the year 2016 with the original data of China Customs.

≥28.0

On November 23, 2022, the General Court of the European Union reversed the conclusion that titanium dioxide was carcinogenic and released a statement (1,2):

“First, the Commission made a manifest error in its assessment of the reliability and acceptability of the study on which the classification was based and, second, it infringed the criterion according to which that classification can relate only to a substance that has the intrinsic property to cause cancer.”
 
As part of our mission at CRIS we base our safety assessments on the currently available scientific evidence and consider many variables (e.g., study quality, journal of publication, etc.), even if it goes against previous conclusions. Evidence-informed decisions making is critical to ensure that the laws and regulations put into place are for the benefit of the population.
 
The EU General Court maintains that the scientific evidence presented wasn’t the complete picture for the ingredient, “in the present case, the requirement to base the classification of a carcinogenic substance on reliable and acceptable studies was not satisfied.”

One of the main challenges that manufacturers face when it comes to buff percentage is ensuring consistency. Variations in the level of coating on titanium dioxide particles can lead to differences in color, opacity, and other properties in the final product. This can be especially problematic in industries such as paint and coatings, where consistency is critical for achieving the desired results.

While the conclusions of the EU expert panel were considered in this report, Health Canada's Food Directorate conducted its own comprehensive review of the available science. This included evaluating new scientific data that addressed some of the uncertainties identified by the EU expert panel and were not available at the time of their review.