I'd set the blocks together last year and put it away when I made a nasty discovery. I'd used some scraps from a friend and I think this blue and white fabric must have had some spray glue or something on it.
I've got this far unpicking rows and setting them back together and I'm pretty bored by now. I'll be glad when it's done and I can get onto something else with a clear conscience. I think I'll examine gifted scraps a bit more closely in future and I might save myself some hassle.