Carbaryl is a chemical in the carbamate family used chiefly as an insecticide. Carbaryl is a cholinesterase inhibitor and is toxic to humans. It is classified as a likely human carcinogen by the United States Environmental Protection Agency. A study reports that carbaryl is a structural mimic of the neurohormone melatonin and directly binds to MT2 melatonin receptor. This could significantly impact circadian rhythms and increase risk for diabetes and metabolic disorders.