Carbaryl is an insecticide used on a variety of crops. Acute (short-term) and chronic (long-term) occupational exposure of humans to carbaryl has been observed to cause cholinesterase inhibition, and reduced levels of this enzyme in the blood cause neurological effects. These effects appear to be reversible upon discontinuation of exposure. Headaches, memory loss, muscle weakness and cramps, and anorexia are caused by prolonged low-level exposure to carbaryl resulting from cholinesterase inhibition. EPA has classified carbaryl as a Group D, not classifiable as to human carcinogenicity.