This webpage is maintained by the Centers for Disease Control and Prevention (CDC). The webpage provides information and resources on Nicotine. "Nicotine is a naturally occurring toxic chemical found in tobacco plants. It has a fishy odor when warm. Cigarettes, cigars, other tobacco products, and tobacco smoke contain nicotine. Worker exposure may occur during processing and extraction of tobacco. At one time, nicotine was used in the United States as an insecticide and fumigant; however, it is no longer produced or used in this country for this purpose. Nicotine affects the nervous system and the heart. Exposure to relatively small amounts can rapidly be fatal."
Centers for Disease Control and Prevention: http://www.cdc.gov/