Till receipts could be causing conditions from diabetes to cancer, US researchers have claimed.
Bisphenol A (BPA) is used as a print developer in thermal paper cash register receipts. And, according to the University of Missouri team, the way it interacts with hand creams means it's more easily absorbed into the body than previously believed.
Thanks to the way it affects hormones, BPA has been associated with a wide range of health conditions. While it's used widely to line plastic and tin food packaging, it's banned in baby bottles.
"BPA first was developed by a biochemist and tested as an artificial oestrogen supplement. As an endocrine disrupting chemical, BPA has been demonstrated to alter signaling mechanisms involving oestrogen and other hormones," says Professor Frederick vom Saal.
"BPA exhibits hormone-like properties and has been proven to cause reproductive defects in fetuses, infants, children and adults as well as cancer, metabolic and immune problems in rodents."
The problem with till receipts, says vom Saal, is the way the BPA on the surface interacts with skin care products such as hand sanitisers, hand creams and soaps. The team tested this by asking volunteers to clean their hands with sanitiser and then handle a till receipt, before eating a plate of French fries. And, they found, the creams meant the BPA was absorbed very quickly, showing up in the volunteers' blood and urine within 90 minutes.
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"Our research found that large amounts of BPA can be transferred to your hands and then to the food you hold and eat as well as be absorbed through your skin," says vom Saal.
"BPA from thermal papers will be absorbed into your blood rapidly; at those levels, many diseases such as diabetes and disorders such as obesity increase as well. Use of BPA or other similar chemicals that are being used to replace BPA in thermal paper pose a threat to human health."
The European Food Safety Authority, EFSA, last year concluded that BPAs represented no serious risk to anyone except young children - the reason it's still allowed in food packaging. But that decision is currently under review.
"This chemical has been used for decades, and it is shocking that the scale of this exposure has only just been identified," says Michael Warhurst of campaign group Chem Trust.
"This research is also important for the huge number of businesses – notably retailers – that are using thermal paper. It's also very relevant for the workers working within these businesses, many of whom will touch a lot of thermal paper during their working day."
The French government has recently proposed that the EU should ban the use of BPA in thermal papers such as till receipts. "This worrying new research considerably strengthens the case for rapid action to bring in this ban," says Warhurst.
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