Toxicity
The acute toxicity of n-hexane is low, although it is a mild anesthetic. Inhalation of high concentrations produces first a state of mild euphoria, followed by somnolence with headaches and nausea. The toxicity of n-hexane has been extensively discussed by the Agency for Toxic Substances and Disease Registry.
The long-term toxicity of n-hexane in humans is well known. Extensive peripheral nervous system failure is known to occur in humans chronically exposed to levels of n-hexane ranging from 400 to 600 ppm, with occasional exposures up to 2,500 ppm. The initial symptoms are tingling and cramps in the arms and legs, followed by general muscular weakness. In severe cases, atrophy of the skeletal muscles is observed, along with a loss of coordination and problems of vision. Similar symptoms are observed in animal models. They are associated with a degeneration of the peripheral nervous system (and eventually the central nervous system), starting with the distal portions of the longer and wider nerve axons. The toxicity is not due to hexane itself but to one of its metabolites, hexane-2,5-dione. It is believed that this reacts with the amino group of the side chain of lysine residues in proteins, causing cross-linking and a loss of protein function.
Chronic intoxication from hexane has been observed in recreational solvent abusers and in workers in the shoe manufacturing, furniture restoration and automobile construction industries, and recently, plastic recyclers and assemblers and cleaners of capacitive touch-screen devices.
In 1994, n-hexane was included in the list of chemicals on the US Toxic Release Inventory (TRI). In 2001, the U.S. Environmental Protection Agency issued regulations on the control of emissions of hexane gas due to its potential carcinogenic properties and environmental concerns.
Read more about this topic: Hexane