Chemicals used to make till receipts could raise the risk of developing harmful diseases such as diabetes, obesity and even cancer, scientists claim.
Alarming research suggests that a substance used to produce paper in store tills, credit card machines and ATMs could be absorbed into the blood stream.
Researchers say the chemical bisphenol-A - widely known as BPA - can disrupt hormones, raising the risk of a wide number of health problems.
The chemical has already been banned in baby bottles in Europe because of safety fears.
But the transparent resin is still used to line most plastic and tin food packaging - despite the calls for an all-out ban by campaigners.
The UK Food Standards Agency says strict regulations mean that the health risk from food packaging is minimal.
But new American research suggests that the higher concentrations of BPA on thermal paper in till receipts - which is not regulated in the same way - poses a different route for the chemical to enter the body.
Scientists at the University of Missouri have found that it can enter the blood stream through the skin.
BPA is absorbed more quickly when it combines with other substances including suncream, soap or hand sanitizer, they said.
They also warn that people could digest the chemical if they wipe their mouth after handling a till receipt - a risk that is particularly high in restaurants.
EFSA - the European Food Safety Authority - last year found that BPA posed no appreciable health risk to anyone apart from very young children.
The organisation found that till receipts counted for no more than 15 per cent of exposure to the chemical, with the vast majority of the minimal concentrations of BPA in the human body coming from food packaging and diet.
EFSA is currently reviewing its findings, with a new report due by Christmas.
But the US scientists said till receipts are a much greater threat than previously thought.
Professor Frederick vom Saal, whose work is published in the journal PLOS One, said BPA had been shown to interfere with oestrogen, the female fertility hormone, and other vital chemical balances in the human body.
‘Store and fast food receipts, airline tickets, ATM receipts and other thermal papers all use massive amounts of BPA on the surface of the paper as a print developer,’ he said.
‘The problem is, we as consumers often have hand sanitizers, hand creams, soaps and sunscreens on our hands that drastically alter the absorption rate of the BPA found on these receipts.’
In the study, researchers tested human subjects who cleaned their hands with hand sanitizer and then held thermal paper receipts.
In a second test, the participants who had handled the thermal paper then were given chips to eat with their hands.
The result was that BPA was absorbed very rapidly, Professor vom Saal said.
‘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,’ he said.
‘BPA exhibits hormone-like properties and has been proven to cause reproductive defects in foetuses, infants, children and adults as well as cancer, metabolic and immune problems in rodents.
‘BPA from thermal paper will be absorbed into your blood rapidly; at those levels, many diseases such as diabetes and disorders such as obesity increase as well.
‘Using BPA or other similar chemicals that are being used to replace BPA in thermal paper poses a threat to human health.’
British safety campaign group the CHEM Trust called for an all-out ban for BPA in till receipts.
Elizabeth Salter Green, director of the group, said: ‘Till receipts are such a routine part of daily life, yet this research shows that bisphenol A used in them can rapidly move through our skin and into our bloodstream.
‘This chemical has been used for decades and it is shocking that the scale of this exposure has only just been identified.’
