More than 15% of the more than 420 Flemish teenagers examined have too high a mix of four so-called perfluorinated compounds or PFAS in their blood. This is evident from a recent update of the Flemish Human Biomonitoring Programme. A calculation last year, based on less strict European standards, showed exceedances in only 3% of the teenagers examined. EU legislation considers the perfluorinated compounds PFOS and PFOA as hazardous substances.