Regulatory authorities are increasingly finding potentially toxic PFAS chemicals in the air, soil, and water — including the drinking supply. In Japan, the government has yet to introduce strict regulations targeting these so-called "forever chemicals," partly because research has not definitively established a causal link between PFAS and serious illnesses. Using public data, NHK put together a map showing where contamination levels have been reported in tap water across the country. In one town, the concentration was nearly 30 times the government target. The residents are angry — and some are demanding to know if their health problems are related. We went to a potential source of the contamination, and also looked at other possible contaminating sources in Japan, and asked an expert what the government needs to do to address this increasingly serious public health issue.