Most notably, a European Food Safety Authority safety assessment published in May 2021 pointed to genotoxicity concerns, as suggested by previous research. Genotoxicity is the ability of chemicals to damage genetic information such as DNA, which may lead to cancer.

Drobne et al. used the terrestrial arthropod Porcellio scaber as a test organism for determining the cytotoxic effect of TiO₂ NPs (anatase). The animals were exposed to TiO₂ NPs of two different sizes (25 nm and 75 nm) in the concentration range 10–1000 μg TiO₂/g dry food for 3 to 14 days. No adverse effects, such as mortality, body weight changes or reduced feeding, were observed. In fact, quite the opposite, an enhanced feeding rate, food absorption efficiency and increase in catalase activity were observed. The intensity of these responses appeared to be time- but not dose-dependent. It should also be noted that the concentrations tested in this study were much higher than the predicted concentration (4.8 μg/g soil) at high emission scenario of nano-sized TiO₂. Using the same test organism another group showed that exposure to TiO₂ NPs induced destabilization of cell membrane in the epithelium of digestive glands isolated from exposed animals. They also showed that this effect can be observed after just 30 minutes of exposure.

Assessment of biocompatibility in eukaryotic cells