A new study finds that technologies installed to remove forever chemicals from drinking water are also doing double-duty by removing harmful other materials—including some substances that have been linked to certain types of cancer. The study, published Thursday in the journal ACS ES&T Water, comes as the Trump administration is overhauling a rule mandating that water systems take action to clean up forever chemicals in drinking water. Last year, the Biden administration finalized a rule establishing the first-ever legal limits of PFAS in drinking water, setting strict limits for six kinds of PFAS chemicals and mandating that water utilities needed to clean up drinking water under these limits by 2029. The study looks at three types of water filtration technologies that have been proven to remove PFAS. Most routine water disinfection processes in the US entail adding a chemical—usually chlorine—to the water.