Bisphenol A (BPA) is a synthetic chemical compound widely used in manufacturing plastics and epoxy resins. It is also a common component in thermal paper receipts, where it functions as a color developer, allowing text and images to appear without traditional ink. BPA is classified as an endocrine disruptor, meaning it can interfere with the body’s natural hormonal systems. Since thermal paper is common in daily life, understanding how to identify and minimize exposure to this chemical is a significant public health topic.
Understanding Thermal Paper Chemistry
Thermal paper printing relies on a coating containing a colorless dye and a chemical developer, which is often Bisphenol A or a related compound. When a thermal print head applies localized heat to the paper, the dye and the developer melt and react, producing the dark image of the printed text. This system makes fast, inkless printing possible for point-of-sale systems worldwide.
The central issue with BPA in thermal paper is that it is not chemically bound within the paper structure. Instead, the BPA exists as a fine powder coating on the surface, which makes it easily available for transfer. This “free” BPA can be present in high concentrations, with some receipts containing a concentration 250 to 1,000 times greater than the amount found in a can of food.
Identifying BPA Receipts at Home
While definitive confirmation requires laboratory testing, a simple physical test can confirm if a receipt is thermal paper, the type that contains bisphenols. Thermal paper is typically thin and has a characteristic slick or slightly glossy finish. The most reliable at-home method is known as the “scratch test,” which uses friction to generate heat.
To perform this test, firmly rub the printed side of the receipt with a coin, a paperclip, or even a fingernail. If the paper is thermal, the friction from this action will cause the coated surface to turn dark, leaving a distinct, dark gray or black mark. This dark mark indicates the presence of the heat-sensitive chemical coating, which likely contains a bisphenol like BPA or its replacement, Bisphenol S (BPS).
Thermal papers may also react to solvents, such as a small drop of hand sanitizer or oil-based lotion, which can cause the paper to turn dark. However, this test only confirms the paper is thermal and cannot distinguish between BPA-containing and BPA-free receipts. A visual inspection for a “BPA-free” label is the only quick way to know if the paper is not using BPA, though this does not guarantee the absence of other bisphenols.
How BPA Enters the Body and Potential Health Effects
The primary route of exposure to BPA from receipts is dermal absorption, meaning the chemical is absorbed directly through the skin. Studies have shown that even a brief handling time of a receipt, around 10 seconds, can lead to the transfer of BPA from the paper to the hands. This transfer is significantly increased if the skin is moist, oily, or has recently been treated with products like hand sanitizer or lotion.
Once on the skin, the “free” BPA can pass through the skin barrier and enter the bloodstream. Cashiers and retail workers who handle receipts frequently throughout the day show significantly higher levels of BPA in their urine compared to the general population, highlighting the risk of chronic exposure. The concern with BPA exposure is its function as an endocrine-disrupting chemical, which allows it to mimic the natural hormone estrogen.
By interfering with the body’s hormonal signaling, BPA has been linked in various studies to potential adverse effects on reproductive health, brain development, and metabolic function. Although the exposure from a single receipt is generally low, the risk comes from cumulative, repeated contact, especially for high-risk groups such as pregnant women and children. The European Union has recognized this concern by prohibiting BPA in thermal paper above a certain low concentration, effectively preventing its use.
Safe Handling Practices and Alternatives
Minimizing contact time is the most immediate and effective action for reducing exposure to bisphenols from thermal paper receipts. Avoid unnecessary handling of the paper, and never crumple or tear the receipt, as this action increases the chemical transfer to the skin. A simple but effective practice is to wash your hands immediately after handling any thermal receipt, especially before preparing food or eating.
A better long-term strategy is to opt for digital receipts, email copies, or text messages whenever the option is available. This eliminates the physical paper entirely and removes the exposure risk. When a paper receipt is necessary, it should be stored separately from currency, food, or other items that may be touched frequently.
In response to health concerns, many manufacturers have shifted away from BPA, often replacing it with Bisphenol S (BPS). While BPS is structurally similar to BPA and also acts as an endocrine disruptor, some research suggests it may be less potent than BPA. The safest alternatives currently available are phenol-free papers, which use non-bisphenol developers like Pergafast 201 or vitamin C.