Relative Density Among commonly used white pigments, lithopone has the smallest relative density. Among white pigments of the same mass, titanium dioxide has the largest surface area and the highest pigment volume.

Additionally, the committee noted that the available data did not provide convincing evidence of genotoxicity for titanium dioxide as a food additive, but recognized the limitations in current methodologies with respect to the testing of poorly soluble particulate materials. Although there were uncertainties in the genotoxicity data, the experts took into account the fact that the additive was not carcinogenic in adequately conducted two-year studies in mice and rats at doses of up to 7,500 mg/kg BW per day for mice, and 2,500 mg/kg BW per day for rats, the highest doses tested. There was also no evidence of reproductive or developmental toxicity in studies in rats at doses up to 1,000 mg/kg BW per day, the highest doses tested.  

JECFA previously assessed titanium dioxide at its 13^th meeting, at which time the expert committee assigned a “not specified” ADI for the additive due to an absence of significant absorption and a lack of toxicological effects in the available experimental animal and human studies. Since its original evaluation by JECFA, titanium dioxide has become a public point of contention, with its ban being introduced (and then subsequently withdrawn) in California legislation in 2023, a legal battle playing out in the EU over the additive’s ban and classification as a carcinogen in 2022, and the European Food Safety Authority (EFSA) calling titanium dioxide unsafe. However, supporters of titanium dioxide say that claims about its dangers are founded in unreliable studies, and some recent research has supported its safety as a food additive.