Environmental Monitoring of Benzene for Safety

When conducting business operations, protecting both people and the environment is critically important, and for those operating in the UK, it is necessary to be familiar with the requirements of the Control of Substances Hazardous to Health (CoSHH) regulations and the Code of Federal Regulations (CFR) in the US.

Comparable legislation exists around the world, the common theme being an onus on identifying hazards, risk assessment and the conditions of appropriate control measures.

The Basics of Detecting Benzene

Properties | Exposure | Detection

Hazardous chemicals that present a danger to human health are present in a number of raw materials, including oil. Usually, these are transported safely and contained within reaction vessels and process pipework during standard plant operation.  

However, procedural maintenance and plant repair (planned turnaround) or a sudden release, due to defective flanges on valves, for example, can potentially expose workers to hazardous chemicals above the legal occupational exposure limit (OEL).

Benzene, a hydrocarbon and volatile organic compound (VOC), is one such hazardous chemical.

Found in oil refining, Benzene is an intermediary in the large-scale manufacture of many commonly used plastics. According to the World Health Organisation (WHO), there is no level of exposure deemed safe.1

“Human exposure to Benzene has been associated with a range of acute and long-term adverse health effects and diseases, including cancer and aplastic anaemia. Public health actions are needed to reduce the exposure of both workers and the general population to benzene.”2

Benzene Exposure

Workers might be exposed to Benzene during certain jobs, for example, in:

  • Chemical and petrochemical plants
  • Coke works
  • Foundries
  • Oil refineries
  • The storage, distribution and use of petrol or Benzene itself 

The World Health Organisation (WHO) and the International Agency for Research on Cancer (IARC) classify Benzene as a group one carcinogen in relation to a long-term (chronic) health perspective.

Environmental Monitoring of Benzene for Safety

Image Credit: Ion Science

Extended exposure to elevated concentrations of Benzene can cause leukemia and affects red and white blood cells.

The WHO has committed to setting a standard for ambient benzene concentrations, declaring that there is no safe level of exposure. However, several countries use their own annual average standard of 3.6g m-3, which is equivalent to 1 part per billion (ppb) or 0.001 ppm.

Benzene Detection

Instead of relying on human senses in the workplace, it is recommended to use a proper form of quantitative monitoring.

Benzene has a low IE value and tends to be present in combination with other chemicals, including aromatics. A proprietary 10.0 eV lamp is only able to detect the aromatics, and should the total aromatic compounds (TAC) exceed regulatory limits, a benzene pre-filter tube can be employed for an accurate reading. 

It is crucial that any PID is well-maintained because of the potential for contaminating the lamp due to humid, dirty environments. The PID also requires calibration using a reference gas each time it is used.

Environmental Monitoring of Benzene for Safety

Image Credit: Ion Science


  1. ECHA (European Chemicals Agency)
  2. The World Health Organisation 

This information has been sourced, reviewed and adapted from materials provided by Ion Science.

For more information on this source, please visit Ion Science.


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