TiO₂ NPs appeared to be more toxic to nematode Caenorhabditis elegans than submicron-sized TiO_2.  At a concentration of 1 mg/l, 7 nm particles affected its fertility and survival rate and were more toxic than 20 nm anatase particles. Similarly, Hu et al. showed that rutile particles (10–20 nm), at concentrations above 1 g/kg soil, can be bio-accumulated in earthworms, where they induce oxidative stress, inhibit the activity of cellulase and induce DNA and mitochondrial damage.

Risk managers at the European Commission and in EU Member States have been informed of EFSA’s conclusions and will consider appropriate action to take to ensure consumers’ protection.

Food containing titanium dioxide that is lawfully placed on the EU market before 7 August 2022 may remain on the market until its date of minimum durability or its ‘use-by’ date has passed. Food produced or placed on the market after 7 August 2022 cannot contain titanium dioxide. The ban on the use of titanium dioxide is effective in each EU Member State, and in Northern Ireland. Some third countries, such as the United Kingdom (excluding Northern Ireland), continue to permit the use of titanium dioxide.

While loose titanium dioxide presents a problem, titanium dioxide within sunscreen formulations presents a much safer option than conventional sunscreen chemicals like oxybenzone and octinoxate. However, titanium dioxide may become dangerous when it is nanoparticle size. Generally, nanoparticles can be 1000 times smaller than the width of a human hair. Despite nanoparticles becoming increasingly common across industries, they have not been properly assessed for human or environmental health effects, nor are they adequately regulated. Researchers don’t quite understand the impacts nanoparticles could have on human health and the environment. However, because of their infinitesimally small size, nanoparticles may be more chemically reactive and therefore more bioavailable, and may behave differently than larger particles of the same substance; these characteristics may lead to potential damage in the human body or ecosystem.

Prof. Maged Younes, Chair of EFSA’s expert Panel on Food Additives and Flavourings (FAF), wrote of the decision: “Taking into account all available scientific studies and data, the Panel concluded that titanium dioxide can no longer be considered safe as a food additive. A critical element in reaching this conclusion is that we could not exclude genotoxicity concerns after consumption of titanium dioxide particles. After oral ingestion, the absorption of titanium dioxide particles is low, however they can accumulate in the body.”

Because of their small size, nanoparticles may have unique physical and chemical properties. These properties may cause them to interact with living systems differently than larger materials with the same chemical composition (also known as bulk materials).

Some food products will include titanium dioxide on their nutrition label. But again, it can be hard to tell for those who don't list the ingredient. 

Titanium dioxide is an insoluble mineral, meaning it cannot dissolve in water. Known for its bright, white pigment, manufacturers use titanium dioxide in many different capacities, including in cosmetics, foods, and drugs. 

The evidence also suggests that the toxicity of TiO₂ particles may be reduced when eaten as part of the diet. This is because proteins and other molecules in a person's diet can bind to the TiO₂ particles. This binding alters the physical and chemical properties of the particles, which influences how they interact with cells, tissues and organs.

Natural barite and anthracite containing more than 95% barium sulfate are mixed and fed at a ratio of 3:1 (mass). After being crushed to a diameter of less than 2cm, it enters the reduction furnace. The furnace temperature is controlled to be 1000-1200°C in the front section and 500-500 in the back section. 600°C, the reduction furnace rotates at a speed of 80 seconds per revolution, and the reaction conversion rate is 80% to 90%.

Relative to a lot of other things that people should be concerned about, titanium dioxide in my mind, is really low on the list. I would be more worried about some substitutes that people are using for titanium dioxide that don't have decades of research associated with it, said Westerhoff.