Those little slips of paper that accumulate in our pockets and purses may do more than just document recent take-out meals, pumpkin spice lattes and shopping sprees. Receipts, according to a small study published Wednesday, could also deliver a potentially harmful rush of hormone-scrambling chemicals into our bodies.
The new research adds fuel to a heated public health debate, hinting that bisphenol A, or BPA -- a primary ingredient in thermal receipt paper used in cash registers, ATMs and some airline tickets -- might more readily leach from the paper and absorb through the skin than previously thought. Men and women in the study who held receipts after using hand sanitizer had up to 185 times more BPA clinging to their skin after one minute, as compared to those who did the same with dry hands. Results also suggested that, after the exposure, BPA in the blood rose to levels previously linked to increased risks of heart disease and diabetes.
"This completely unravels the FDA's position that BPA is safe," said co-author Frederick vom Saal, an environmental health expert at the University of Missouri-Columbia.
Scrutiny over BPA has been building in recent years, as researchers continue to uncover evidence that associates exposure to even minute amounts of the chemical -- most well known for its presence in food packaging and water bottles -- with health problems, from attention-deficit disorder and asthma to diabetes and cancer. As a result of consumer concerns, a number of BPA-free products have flooded the market. However, some "BPA-free" products have been found to contain low doses of a popular substitute chemical, bisphenol S (BPS), which can mimic or block natural hormone messengers in much the same way as its chemical cousin, and may even persist longer in the environment.
Still, studies have generally failed to show how harmful levels of BPA or BPS enter the bloodstream, explained vom Saal. Many researchers and regulators have "ignored" exposure through the skin or lining of the mouth, he said, focusing too narrowly on the ingestion of the chemicals. BPA is metabolized fairly efficiently in the stomach, which leaves little to enter the bloodstream. So while consuming BPA is a concern, he said, it may be outmatched by other routes of exposure.
The FDA has underscored the stomach's ability to break down BPA in its evaluation of the research. "Based on FDA's ongoing safety review of scientific evidence, the available information continues to support the safety of BPA for the currently approved uses in food containers and packaging," Theresa Eisenman, a spokeswoman with the FDA, said in an email to The Huffington Post.
Receipts, however, are outside of the agency's purview. In a report released in January, the EPA discussed its own concerns about the chemical and encouraged efforts to halt the use of BPA in receipts.
The chemical industry maintains that the practice is safe.
"The most relevant data shows very little BPA exposure under conditions most representative of real-life contact with thermal receipt paper," Steven G. Hentges, of the American Chemistry Council's Polycarbonate/BPA Global Group, wrote to HuffPost.
"Also, available data suggests that BPA is not readily absorbed through the skin," he added, referring to previous studies that found lower levels of BPA seeping through the skin. Participants in that research did not use skin care products prior to handling receipts.
Human skin does provide a reasonably effective barrier to chemicals in the environment. The new study, however, suggests human ingenuity, in attempting to achieve other ends, may inadvertently compromise that protection. Soaps, sunscreens, sanitizers and other skin care products often contain mixtures of chemicals designed to break down the skin's dermal barrier, allowing a product to more easily penetrate into the skin where it can better do its cleaning or moisturizing.
Cosmetic products themselves sometimes contain potentially dangerous chemicals such as phthalates, parabens and even BPA, said Laura Vandenberg, a researcher at the University of Massachusetts, Amherst, who was not involved in the new study. And if those temporarily opened channels do enable other chemicals to travel through our skin, she said, the implications could be profound.
"Receipts are something we all come into contact with," said Vandenberg, adding that she's seen cashiers and customers in cafeterias place receipts on soups, under sandwiches and even use them as napkins -- increasing the risk of both BPA absorption and ingestion. In fact, the new study found BPA was transferred from the participants' fingers onto French fries as they were eaten.
Still, experts caution that the study is small and more research is needed to better understand just how much exposure different people could face. There are already hints that women could face higher risks than men, likely due to thinner skin and greater use of cosmetic products.
But small changes in the use of thermal receipts are already underway, including moves by a few U.S. businesses to rid their receipts of BPA.
Jon Stewart, 29, handles receipts eight hours a day while working the cash register at a PCC Natural Market in Seattle. Until three weeks ago, the receipts he printed and handed to customers at his store contained BPS. That paper had replaced PCC's BPA-based receipts a few years ago after concerns arose of its safety.
On Sept. 29, PCC Natural Markets became the first grocery store chain in the country to roll out a BPA- and BPS-free receipt paper in all of its stores. The paper, developed by Wisconsin-based Appvion, Inc., uses vitamin C as an alternative thermal developer. "We thought this was the best thing we could do for our shoppers and our staff," said Diana Chapman, director of sustainability for PCC.
Stewart said that he is "stoked" with the change. "If it means fewer chemicals I have to handle, I'm all for it," he told HuffPost, noting that customers have frequently expressed their appreciation for the change. He also noted that fellow cashiers sometimes keep bottles of hand sanitizer at their registers.
"Eventually we'd like to go to electronic receipts," said Chapman, "but we're not there yet."
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