Canadian health authorities have issued a precautionary recall for masks containing graphene—a nanomaterial made up of a single layer of carbon atoms—citing the need to study health risks after a study in animals found the substance had “some potential” to cause lung toxicity. The recall, issued Friday by Health Canada, urges Canadians not to use masks that contain graphene or biomass graphene because of the potential for the tiny particles to be inhaled, which may pose a health risk. The advisory cites research showing that inhaled graphene particles “had some potential to cause early lung toxicity in animals” although it noted that the health risk to humans is still unknown and requires further study. Health Canada said it is working with manufacturers of the masks to assess their potential impact on people’s health. “Until the Department completes a thorough scientific assessment and has established the safety and effectiveness of graphene-containing …