A perchlorate is a chemical compound containing the perchlorate ion, ClO−4. The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Perchlorate contamination in food, water, and other parts of the environment has been studied in the U.S. because of harmful effects on human health. Perchlorate ions are somewhat toxic to the thyroid gland.