A chemical previously banned or voluntarily removed from most plastic food containers still coats most thermal paper receipts, and this method of exposure results in higher and prolonged levels in blood.
Bisphenol A, also known as BPA, gained notoriety in 2010 when Canada became the first nation to declare it toxic. BPA was commonly used in hard plastic bottles and food containers. Canada went on to ban the import and sale of baby bottles and sippy cups that contain BPA, as its ability to interact with estrogen put children at highest risk of fertility issues and increased incidence of breast and prostate cancer. The BPA-free movement prompted many companies to voluntarily pull BPA from their products and containers.
While this certainly helped reduce exposure to BPA, BPA in food containers is largely bound, but the BPA that coats receipts is designed to easily scratch off during printing. Concentrations are higher, and it easily rubs off onto the hands that handle them, or anything else they might touch. Not only could this be ingested, BPA can also directly absorb through the skin and into the bloodstream.
A single paper receipt can contain up to 1,000 times more BPA than a plastic bottle, and it readily rubs off in minutes instead of leaching out over years of use.
This is bad news for all consumers, but especially concerning for workers who routinely handle receipts and other documents printed on thermal papers, like airplane boarding passes, admission tickets, and even prescription labels.
New research at the University of Alberta has shown that BPA, when absorbed through the skin, metabolizes more slowly than when it is ingested.
Handling a piece of BPA-containing thermal paper for five minutes resulted in measurable levels of BPA in urine samples for a full week. Eating a BPA-laced cookie resulted in a spike in BPA levels in urine within five hours, which was fully cleared within a day. Digestive enzymes in the liver and intestines may help promote clearance, a mechanism that would be bypassed in the case of skin exposure.
This study was done with dry handling, and previous research from the University of Missouri demonstrated that even more BPA is absorbed when thermal paper is handled after using hand sanitizer.
The concentrations found were still well below lethal levels, but knowing that skin absorption can be such a big contributor to BPA exposure means that more research is needed to determine health risks.