A recent study has purportedly found that “a very large amount of BPA [bisphenol A] is transferred from thermal paper to a hand as a result of holding a thermal receipt for only a few seconds immediately after using a product with dermal penetration chemicals.” Annette Hormann, et al., “Holding Thermal Receipt Paper and Eating Food After Using Hand Sanitizer Results in High Serum Bioactive and Urine Total Levels of Bisphenol A (BPA),” PLOS One, October 2014. Designed to mimic scenarios common in fast-food restaurants, the study measured dermal, serum and urine BPA levels in subjects asked to use hand sanitizer, handle a receipt and then consume 10 french fries.

The data evidently showed that holding a thermal receipt for 45 seconds after using a hand sanitizer “resulted in the maximum amount of BPA that was swiped from the palm and fingers,” though this measurement “likely underestimates the amount of free BPA transferred from the print surface of thermal paper.” Noting that hand sanitizers often contain “dermal penetration enhancing chemicals that can increase by up to 100 fold the dermal absorption of lipophilic compounds such as BPA,” the study’s authors reported that “there was a dramatic increase” in serum unconjugated BPA in both men and women who handled receipt paper after using sanitizer. They also found a high level of urine total BPA (approximately 20 μg BPA per gram of creatinine) collected 90 minutes after dermal and oral exposure to the substance.

“Our study provides the first data that thermal paper may be a significant factor in accounting for high levels of bioactive BPA in human serum and total BPA in urine that have been associated with diseases that are increasing in frequency in human populations,” concluded the University of Missouri researchers. “Our findings also suggest that the impact of the use of dermal penetration enhancing chemicals in skin care products on transdermal absorption of environmental contaminants should be taken into consideration in risk assessments and should be a priority for future research.”