A study by the University of Notre Dame found high levels of harmful 'forever chemicals' in 15 of 22 analyzed brands of smart watches, including those from Nike, Apple, Fitbit, and Google. These chemicals, linked to health issues like cancer and liver disease, are commonly found in fluoroelastomers used in watch bands.A study by the University of Notre Dame found high levels of harmful 'forever chemicals' in 15 of 22 analyzed brands of smart watches, including those from Nike, Apple, Fitbit, and Google. These chemicals, linked to health issues like cancer and liver disease, are commonly found in fluoroelastomers used in watch bands.