mind & bodyanalysisThe Conversation
Are there toxic chemicals in your grocery store receipt?
Thermal receipt paper is coated with a developer, usually bisphenol A or bisphenol S, that reacts with a colourless dye when heated, turning the printed area black. Bisphenols are endocrine disruptors, chemicals that can interfere with hormones such as estrogen, and at high exposures they have been linked to health problems. Touching a receipt does transfer small amounts through the skin, and the risk is higher with greasy hands from lotion or sanitizer. Still, a 2023 estimate put the dose from receipts for the average person thousands to millions of times below European food safety standards, and roughly 100 times higher for people who handle receipts all day. Most bisphenol exposure comes from food and drink containers. Pregnant people, infants, children and people with endocrine disorders are the groups toxicologists suggest should avoid handling thermal receipts.
Thermal paper has a coating that contains a developer and a colourless dye. Heat from the printer melts the coating, the developer and dye react, and the dye turns black. Because the chemicals sit on the paper's surface, they can transfer to skin, and oils on the hands can speed absorption.
The receipt scare shows how a toxicology principle works in practice: the dose makes the poison. Exposure is real but small for most people, and the bigger sources are packaging. Switching to bisphenol-free paper or emailed receipts are simple ways to reduce it.
The principle that the dose makes the poison was written by the Swiss physician and chemist Paracelsus in 1538.
background
Bisphenol A (BPA) is a chemical compound primarily used in the manufacturing of various plastics. It is a colourless solid which is soluble in most common organic solvents, but has very poor solubility in water. BPA is produced on an industrial scale by the condensation reaction of phenol and acetone. Global production in 2022 was estimated to be in the region of 10 million tonnes.
BPA's largest single application is as a co-monomer in the production of polycarbonates, which accounts for 65–70% of all BPA production. The manufacturing of epoxy resins and vinyl ester resins account for 25–30% of BPA use. The remaining 5% is used as a major component of several high-performance plastics, and as a minor additive in polyvinyl chloride (PVC), polyurethane, thermal paper, and several other materials. It is not a plasticizer, although it is often wrongly labelled as such.
From Wikipedia: Bisphenol A (CC BY-SA 4.0) ↗ · text CC BY-SA 4.0Illustrative photo · IIVQ - Tijmen Stam, CC BY-SA 3.0, via Wikimedia Commons
