https://www.pca.state.mn.us/green-chemistry/bpa-thermal-pape...
Or so they said on AliExpress.
Those blue receipt papers seem okay though: https://www.koehlerpaper.com/en/products/Thermal-paper/Blue4...
"If you must give paper receipts, look for “phenol-free” paper, which is safer for human health and has fewer environmental effects. Three types that do not contain BPA or BPS and are competitively priced contain either ascorbic acid (vitamin C), urea-based Pergafast 201, or a technology without developers, Blue4est. The latter uses a coating that reveals an underlying dark layer when heat is applied."
Cons: fancy paper, fades over time, destroyed by even minor heat.
We switched from dot matrix receipts to thermal a few years ago and there were several very vocal complaints about the relative impermanence of a thermal receipt.
There was essentially no reasonable distance at which we could store the to-go pizzas from their accompanying thermal receipts where information the receipts contained would be recoverable.
Also, the cynic in me says that thermal paper is exceptionally fragile and this benefits return policies. Thermal receipt paper falls apart readily when wet, bleaches quickly, and of course turns black if exposed to too much heat.
It also uses paper in rolls, without requiring spools, and no ink/toner/ribbons to replace which would be both more complicated and take longer.
> The chemicals have been shown to be hazardous to reproductive systems in humans and animals and are linked with obesity and attention disorders.