Titanium dioxide
Health and safety

As of May 2023, following the European Union 2022 ban, the U.S. states California and New York were considering banning the use of titanium dioxide in foods.

The European Union removed the authorization to use titanium dioxide (E 171) in foods, effective 7 February 2022, with a six months grace period.

Titanium dioxide dust, when inhaled, has been classified by the International Agency for Research on Cancer (IARC) as an IARC Group 2B carcinogen, meaning it is possibly carcinogenic to humans. The US National Institute for Occupational Safety and Health recommends two separate exposure limits. NIOSH recommends that fine TiO particles be set at an exposure limit of 2.4 mg/m, while ultrafine TiO be set at an exposure limit of 0.3 mg/m, as time-weighted average concentrations up to 10 hours a day for a 40-hour work week.

As of 2006, titanium dioxide had been regarded as "completely nontoxic". Widely-occurring minerals and even gemstones are composed of TiO. All natural titanium, comprising more than 0.5% of the Earth's crust, exists as oxides. Although no evidence points to acute toxicity, recurring concerns have been expressed about nanophase forms of these materials. Studies of workers with high exposure to TiO particles indicate that even at high exposure there is no adverse effect to human health.
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