The disguise
A receipt is paper in every way that matters to your hands: matte, tearable, unremarkable. No plastic in sight.
The plastic-adjacent chemistry
Thermal paper is coated with a free, unbound developer powder — historically BPA at 1–2% of the paper’s weight. It’s the same endocrine-active molecule as in polycarbonate plastic, except not locked in a polymer — just sitting on the surface, ready to transfer to whatever touches it.
The evidence
Handling receipts measurably raises BPA levels in the body (University of Missouri, 2014) human trial. An ex vivo human-skin study found 25% of BPA applied to skin is absorbed within 24 hours — versus 0.4% for BPS (Annals of Work Exposures and Health, 2021) lab. The EU restricted BPA in thermal paper from January 2020; the dominant replacement is bisphenol S, which ECHA projected would coat 61% of EU thermal paper — while calling it a suspected reprotoxicant and openly lamenting the substitution (ECHA) agency. Australia has no equivalent restriction — assume local receipts are BPA or BPS coated.
The tell — and the fix
The tell: scratch it with a fingernail — thermal paper leaves a dark mark. The fix is the cheapest on this site: say “no receipt, thanks” or take the e-receipt. Beyond that: don’t let kids play with them, don’t store them against food, wash hands before eating if you’ve been handling a stack — and skip the hand sanitiser first, which strips the skin barrier and increases uptake. Spare a thought for checkout staff, who handle thousands a day; the occupational-exposure literature is really about them.