https://www.pca.state.mn.us/business-with-us/bpa-and-bps-in-...

> 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.

> Companies that offer phenol-free alternatives: ...