EU authorities say there is no conclusive evidence of a cancer risk from synthetic face masks and have urged people to keep wearing them after a Belgian study warned last month they may contain carcinogens.
Face masks are widely considered crucial tools to reduce the spread of COVID-19 and have become an everyday item for a large part of the world's population through the pandemic.
A report in October by Belgium's public health body Sciensano said it had found titanium dioxide (TiO2), a potentially hazardous substance, in the synthetic face masks it examined, including commonly worn models.
Titanium dioxide is used as a white colorant and matting agent in masks and textile products, as well as sunscreen, paints and food products such as soups and chewing gums.
The European Commission, the EU's executive arm, said there was currently no evidence to suggest the presence of titanium dioxide in face masks posed a health risk and recommended their continued use.