According to the United States National Toxicology Program, the inhalation exposure toxicity rate of of ethyl cyanoacrylate, or super glue, is safe and additional study is unnecessary. The report also highlighted an extremely large LD50, with over 5000 milligrams per kilogram of body weight required for a lethal dose.
As Steve Harris M.D. explains, super glue was originally used in Vietnam to glue the edges of lacerated wounds, including internal organs such as the liver, back together. According to Dr. Harris, the only reason it was not specifically approved by the FDA for this purpose is that the studies would cost millions, and with ethyl cyanoacrylate already being off patent, there is no research incentive.