While loose titanium dioxide presents a problem, titanium dioxide within sunscreen formulations presents a much safer option than conventional sunscreen chemicals like oxybenzone and octinoxate. However, titanium dioxide may become dangerous when it is nanoparticle size. Generally, nanoparticles can be 1000 times smaller than the width of a human hair. Despite nanoparticles becoming increasingly common across industries, they have not been properly assessed for human or environmental health effects, nor are they adequately regulated. Researchers don’t quite understand the impacts nanoparticles could have on human health and the environment. However, because of their infinitesimally small size, nanoparticles may be more chemically reactive and therefore more bioavailable, and may behave differently than larger particles of the same substance; these characteristics may lead to potential damage in the human body or ecosystem.

With the rise of nanotechnology, research in recent years has also shown the dangers of titanium dioxide (TiO2) nanoparticles, and their genotoxicity, which refers to a chemical agent’s ability to harm or damage DNA in cells, thus potentially causing cancer.