‘Forever chemicals’ is a nickname given to some per- and polyfluoroalkyl substances (PFAS). Many PFAS are highly resistant to high temperatures, oil, water or corrosion. For this reason, they’re used in many products including some fundamental to the energy transition. From wind turbines to solar panels the batteries in electric vehicles and the semiconductor chips at the heart of energy technologies. They’re also used in thousands of everyday products, from non-stick pans to clothing and fire-repellent foam, but these chemicals pose risks to human health. PFAS have been linked to cancer, thyroid disease and low fertility among many other conditions.