The Olympic skiers who recently dazzled the world on Canadian slopes couldn't have reached the speeds they did without ski wax. But the material may have a dark side. Researchers have found perfluorinated octanoic acid (PFOA)—a chemical found in ski wax and nonstick cooking surfaces—in the blood of professional ski waxers at concentrations over 50 times normal, they report online in Environmental Science & Technology. What's more, the substance seems to stick around in the body: Novice ski wax technicians showed a spike in PFOA blood levels during the season that barely diminished in the off-season; experienced technicians sported massive, year-round concentrations similar to those seen in employees at plants manufacturing the chemical. The findings could be cause for concern, as PFOA has been linked to diminished fertility.