Thermal paper is primarily coated with a mixture that includes BPA or its alternatives, such as bisphenol S (BPS). These chemicals are used as developers that react with heat to create an image or text on the paper. BPA is a well-known industrial chemical that has been used to make certain plastics and resins since the 1960s. Due to health concerns, BPS and other bisphenol alternatives are sometimes used as replacements, although their safety profiles are not fully understood.
