No returns

When you’re at the cash register, ringing up your new BPA-free water bottle, the hormone-mimicking chemical bisphenol A might rub off on your fingers from an unexpected source: the sales receipt.

John C. Warner, a researcher who cofounded the Warner Babcock Institute for Green Chemistry, found that a number of the thermal imaging papers used in most cash registers are coated with BPA. According to a Science News story, Warner tested receipts from local stores in a lab, searching for BPA. He found it in many but not all of the receipts. While many worry about the prevalence of BPA in a range of plastics—from water bottles and nursing bottles to food container linings—“the biggest exposures, in my opinion, will be these cash register receipts,” he told Science News.

Warner’s research has not been published and, therefore, not been peer-reviewed. In the meantime, you might want to wash your hands after handling sales receipts.