But that depends on how titanium dioxide is being used and how you might come into contact with it. The International Agency for Research on Cancer (IARC) has classified titanium dioxide as possibly carcinogenic to humans based on studies that showed more lung tumors in rats associated with breathing in titanium dioxide.

Fig. 4. Hemolysis (%) values of samples, A: 0.2 mg/mL P25TiO₂NPs; B: 0.02 mg/mL P25TiO₂NPs; C: 0.2 mg/mL VitaminB2@P25TiO₂NPs; D: 0.02 mg/mL VitaminB2@P25TiO₂NPs after 3 h of irradiation (red) and 6 h (blue). SD <5 for all samples and p <0.05 between C-D and A-B.