Ideally don't buy a thermal printer at all. The paper usually contains BPA. You found one that says BPA free? Yep they switched to BPS. Also toxic and harmful to reproductive health.
If you absolutely must - use a European supplier - both are banned there for thermal paper.
I was about to write an incredulous comment accusing you of licking receipts, but I thought I'd look into it first. It does appear that just handling thermal paper can expose you to BPA [0].
Such a shame, thermal printers are the only printing device I don't suspect of being a plot by Satan to tempt us into wrathful thinking. Thermal printers are insanely reliable, I've worked IT for several businesses with shipping departments and thermal label printers are less troublesome than even keyboards, I struggle to think of a class of equipment that generated less issues. I guess I should have suspected there was something devious about them, they are printers after all and all other printers I've had to support have always just been constant sources of annoying issues.
Oh man... I've definitely crumpled up and put a receipt in my mouth before... probably even eaten one at some point, probably to horrify a girlfriend in my younger days. I know, I'm a gremlin.
That article has a good alternative though: ascorbic acid. I think the last time I looked into this I had a hard time finding thermal labels that used ascorbic acid, but they at least have receipt paper. I do still have concerns that even the ascorbic acid paper still has something bad in it absent any documentation going over the full ingredient list.
Yeah knowledge of it seems pretty thin on the ground despite this being decade+ known. Haven't quite worked out why - unlikely say tobacco it doesn't seem like an industry that would have financial might behind it.
I had the same incredulity when BPA alarms started going off, thinking it was another Prop 65 warning type thing. Finding out that it is literally absorbed through the skin sent shivers down my spine. That stuff is scary.
I use these for printing my shopping lists, I like synced lists (in Todoist in my case), but hate walking through stores with a device in my hand. The Ökobons have the added benefit of me being able to scratch items off the list with my fingernail. Also the blue is cool.
If you absolutely must - use a European supplier - both are banned there for thermal paper.