n-hexane

There was an interesting article in the Guardian a few days ago about the use of n-hexane in a factory in China. The company in question, which produces touch screens fro companies including Nokia, was using the solvent to clean the screens.

N-hexane is one of the organic compounds we study on BOHS Module course M101 ”Effects of hazardous substances”. As an alkane, we wouldn’t expect it to be particularly toxic. Alkanes generally are mild irritants and narcotics (substances that cause depression of the nervous system leading to effects similar to drunkenness). N-hexane is different in that it has been found to have another more serious chronic (i.e. long term) effect. Exposure to the compound can lead to peripheral neuritis – damage to the peripheral nervous system – causing symptoms such as loss of sensation in the fingers. There’s a good summary on the effects of n-hexane here.

The effects on the peripheral nervous systems are not due to the substance itself, but one of it’s metabolites - hexane-2,5-dione. It’s an example where the bitransformation of a substance in the body produces a more toxic compound.
The harmful effects are well known, and in the UK, Europe and the USA companies with a commitment to the health and safety of their workers would avoid using n-hexane wherever possible. It seems that the Chinese company actually used n-hexane as a substitute for the less toxic ethanol. According to the Guardian report about 49 workers were affected. The problem could have been avoided if a serious attitude was taken to health and safety and the principles of occupational hygiene were applied.