These are my opinions, I am not chemist nor in the health field and one can never be very careful but I would be more worried about driving downtown and breathing exhaust pollution everyday than one or two 3d printers emitting some PLA fumes, which I cannot smell when printing at 210C in a home environment. I don't use ABS, which smells bad apparently, and without a heated bed, Flux will not be the right printer for it either. As for the PTFE tube in the heating block steel-tube, it does survive the printing temperatures under 240C and does not deteriorate until 260C (produce toxic fumes) according to what I read. I would be more worried about PTFE coated frying pans than the tube in Flux. Again, my opinions only and one should do what makes one's self feel comfortable!