Amid ongoing health concerns about the chemical bisphenol A (BPA)—which has been banned in plastic baby bottles and voluntarily removed from many other consumer products—you can find more and more "BPA-free" items for sale. The problem is that little or nothing is known about the possible health effects of most of the substances being used to replace BPA. They may be just as bad. Experts sometimes call this "regrettable substitution."
For instance, some recent lab and animal research has raised suspicions about a substitute called BPS (bisphenol S), which is now often used in plastic products and thermal paper. As the name suggests, BPS is related to BPA, and it is also an endocrine disruptor. Though BPS doesn't leach from plastics as readily as BPA does, most Americans now have detectable levels of BPS in their urine, and no one knows if it is safer. The same is true of other bisphenol types, such as BPF.
Here's a sign of the quandary facing both manufacturers and consumers: A 2014 paper from the Environmental Protection Agency looked at 19 potential substitute chemicals for BPA in thermal paper, including BPS. It concluded that there are "no clearly safer alternatives." The best option, it suggested, may be for companies to come up with printing systems that don't use thermal paper.