From 1956 to 1957, the U.S. Air Force’s Arctic Aeromedical Laboratory conducts a study on the role of the thyroid gland in acclimatizing humans to cold, using iodine 131. The study involves 200 administrations of I-131 to 120 test subjects, including 84 Alaska Natives, Eskimos, and 17 Indians. Upon investigation, it is found that the communities were not properly informed of the risks of the study, nor were they properly informed about the study’s purpose (National Center for Biotechnology Information, "The Arctic Aeromedical Laboratory's Thyroid Function Study: A Radiological Risk and Ethical Analysis").