Issues

Whilst benzene remains a very important building block in the chemical industry, concerns over its effect on health have led to steps being taken to reduce the amount released into the atmosphere. Research chemists no longer use it, and its use as a solvent in industry is carefully controlled.

Chemical Plant

Plants producing and using benzene regularly test all pipe joints for leaks, and use safety valves, flanges and gaskets of the highest quality. Emissions on industrial sites are now at very low levels, and will continue to fall.

Petrol

Benzene has been used in some countries to raise the octane rating of unleaded petrol and prevent knocking (fuel combustion that occurs at the wrong time, lowering efficiency and increasing engine wear). Concerns over atmospheric levels of benzene mean that permitted levels are now low (typically around 2%), but road transport still remains the main source of atmospheric benzene.

Other Sources

Benzene is also found in foods, water, and is present in tobacco smoke. This means the total intake for an individual will depend on where they live, what they eat and drink, and if they choose to smoke. A 20 per day smoker living in an urban centre could have a daily intake of up to 1255 mg, which could be up to 10 times that for a non-smoker in a rural location.

Health Effects

  • Benzene is volatile, and most ill effects are the result of inhalation of the vapour.
  • At low levels it produces drowsiness, headaches and vomiting.
  • Higher levels can result in unconsciousness, with very high levels of exposure causing death within a relatively short time (5 - 10 minutes).
  • Long term, low level exposure (such as would be possible with workers in the chemical, oil refinery or waste disposal industries) is of concern as benzene is a known carcinogen (linked to the development of cancer), and can damage the immune system and cell chromosomes.

The Future of Benzene

Benzene will remain an important chemical for some time to come, and production levels are expected to continue to rise. Several processes are in use or development that allow end products, for which benzene is currently the main feedstock, to be made in other ways.

For example, phenolic resins, which account for about 7-8% of benzene production, can be made from waste biomass.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Sources of Benzene intake

 

 


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