Several effects have already been shown in animals. Among these, toxic effects have been identified
in several organs (heart, lungs, kidneys, reproductive system…), as well as genotoxicity and
cytotoxicity. For example, some particles cause granulomas, fibrosis and tumoural reactions in the
lungs. Thus, titanium dioxide, a substance recognized as having low toxicity, shows high pulmonary
toxicity on the nano-scale in some studies and no or almost no effects in other studies.