Abstract

Personal care products may contain SiO₂,ZnO or TiO₂ nanoparticles. Risk estimates regarding thesenanoparticles have so far proven elusive due to large data gaps. Datagaps about hazards of inorganic oxidenanoparticles to humans are smaller but still substantial.There is some recent evidence that amorphous SiO₂,ZnO or TiO₂ nanoparticles may be able to breach the barrier of the stratum corneum. The ability to generate reactive oxygen species is a major molecular determinant of nanoparticle hazard. There is scope for hazard reduction by substitution and by suppressing theability of nanoparticles to generate reactive oxygenspecies. Options for hazard reduction are not reflected in current legislation regarding personal care products inthe USA and the European Union.