The everyday habit of casually handling supermarket receipts or parcel labels can have serious health effects, an expert has warned. In particular, touching thermal paper right after applying hand cream or hand sanitizer can sharply increase the amount of chemicals absorbed through the skin.
According to the medical community Monday, Choi Eun-jung, a doctor of science education at Ewha Womans University, explained the characteristics of and precautions for thermal paper used in receipts and parcel labels.
Thermal paper is a special paper on which letters appear in response to heat. Beyond supermarket receipts, much of the printed material encountered in daily life — including parcel labels, bank queue tickets, parking tickets, and some airline tickets — is produced using this method.
The key issue is the color-developing catalyst used in thermal paper. Bisphenol A (BPA), which was mainly used in thermal paper in the past, has been significantly reduced due to tighter regulations at home and abroad. In Korea, the content is also limited to less than 0.02% of total weight, the same level as the EU.
However, because similar substances such as bisphenol S (BPS) and bisphenol F (BPF) are often substituted in place of BPA, critics point out that a "BPA-free" label alone makes it difficult to avoid bisphenol exposure itself. Some analyses suggest that the amount of bisphenols contained in a single receipt is 250 to 1,000 times that of can containers or baby bottles, where BPA is used in the internal coating.
Caution is needed when holding receipts with hands that have hand cream applied. "There are research findings that bisphenol absorption can increase about 100-fold when hand cream has been applied," Choi said.
The proposed mechanism is that ingredients such as triclosan and triclocarban contained in hand cream act as solvents that dissolve BPA, promoting skin penetration. For the same reason, bisphenols also more easily transfer to the skin when touching receipts right after using hand sanitizer.
According to Swiss researchers, simply holding thermal paper in the hand for five seconds can allow about 0.2 to 6 micrograms of bisphenol A to penetrate the body through the skin. A Seoul National University research team also reported that the urinary bisphenol A concentration of cashiers, who routinely handle receipts, was measured higher than that of the general public.
Bisphenols are classified as endocrine-disrupting substances and can act similarly to the female hormone estrogen in the body. Some studies have raised associations with reduced sperm count, precocious puberty, breast and prostate cancer, and attention deficit hyperactivity disorder (ADHD). A research team at the Korea Institute of Toxicology (KIT) also confirmed through animal testing that chronic BPA exposure can affect nerve cell function, causing increased anxiety and reduced memory. However, further research is underway on the causal relationship and degree of harm of these associations.
It is difficult to conclude that current general exposure levels in Korea cause immediate harm. According to an integrated risk assessment conducted by the National Institute of Food and Drug Safety Evaluation as of 2024, Koreans' total BPA exposure was 0.02% of the human toxicity reference value, a level of low concern, and BPS and BPF also showed margins of exposure safety far exceeding their respective uncertainty factors, so the risk at current exposure levels was assessed as low.
However, this assessment was based on the average of the general public, and a separate assessment for high-exposure groups who handle receipts repeatedly as part of their jobs was not conducted.
Experts recommend washing hands after touching receipts or parcel labels and placing receipts that need to be kept in a separate envelope or zipper bag. Using electronic receipts instead of paper ones, and managing infants and young children so they do not touch thermal paper like a toy, were also suggested as preventive measures.
