As for titanium dioxide, the FDA approved titanium dioxide for use as a food additive in 1966. The last time the agency reviewed the additive’s safety, according to the Guardian, was in 1973.

What titanium dioxide is really emblematic of ... is the failure of FDA to look back at these old decisions and ask whether its decisions that were made in this case ... 56 years ago (in the 1966 approval) still hold up, he said.

No. EFSA’s role was limited to evaluating the risks linked to titanium dioxide as a food additive. This included an assessment of relevant scientific information on TiO₂, its potential toxicity, and estimates of human dietary exposure. Any legislative or regulatory decisions on the authorisations of food additives are the responsibility of the risk managers (i.e. European Commission and Member States).

Abstract

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.

Titanium dioxide remains in many food products in this country because of regulatory folly by the Food and Drug Administration, which allows problematic food ingredients to remain undetected and unreviewed.