Because coating everyday objects in endocrine disrupting chemicals is just plain fun! From HuffPo:
Amazingly, the greatest threat of BPA exposure may be something we handle nearly every day: receipts. According to the Warner Babcock Institute for Green Chemistry's John Warner in a Science News article last year, "The average cash register receipt that's out there and uses the BPA technology will have 60 to 100 milligrams of free BPA." Milligrams? By comparison, the amount deemed worrisome enough by reusable water bottle manufacturer Nalgene to eliminate the chemical from its polycarbonate bottles was measured in nanograms (that's one-millionth of a milligram).
What's especially scary about the receipt scenario is that there's no way to control all the possibilities for exposure -- picture waiters delivering plates of food after handling customers' checks, or shaking hands with someone who just put a receipt in his wallet. What you can control: Decline a receipt if you don't need one (save more trees, too), and wash your hands frequently (good hygiene during flu season, anyway).
Sadly, as far as I know, none of the pending BPA bans on the state or federal level address the use of bisphenol-A in register receipts. And yet that may be how many of us get our largest dose of that nasty chemical (here's more background on BPA). Too bad the FDA thinks its hands are tied when it comes to regulating it.