The EPA recently changed drinking water recommendations for PFOA at 0.004 part per trillion (ppt) and for PFOS, 0.02 ppt. [0] and if my math is correct, 248,000 ppm equates to 2.489e+11 ppt [1] which please correct me if I am wrong, puts Oral-B Glide at 1.2445e+13 times the EPA recommendation for drinking water. While obviously ingesting floss isn't the same as drinking water but that still seems high to me. Like so high that I must have made an error somewhere.
[0] https://cen.acs.org/environment/persistent-pollutants/US-EPA...