Jankovic, J. J. T. E., & Tolosa. (2007). Parkinson's disease and movement disorders. E. Tolosa (Ed.). Lippincott Williams & Wilkins.

Cyanide, usually from the consumption of potassium cyanide or sodium cyanide can result in Parkinsonism. Cyanide is also produced by certain bacteria, fungi, and algae, and are found in a number of foods and plants, such as unprocessed cassava, cherry pits, apricot pits, bitter almonds. Hydrogen cyanide is contained in vehicle exhaust and in tobacco smoke, as does burning plastic. Cyanides are also found in gold processing. Cyanide interrupts the electron transport chain in the inner membrane of the mitochondrion. Cyanide also occupies the place of oxygen in hemoglobin (which transports oxygen). Oxygen is required for the formation of L-dopa. So carbon monoxide may cause Parkinson's disease symptoms by interfering with the availability of oxygen to the brain. However, the precise toxic means by which it causes Parkinson's disease has still not been proven.