Hazard Watch: Clearing the air about Mercaptans and their hazards

Our next article in our Hazard Watch series deals with mercaptans or thiols, and the importance of limiting exposure to them in the workplace.

What are mercaptans?

Mercaptans, (or thiols as they are sometimes called) are an organic compound, known for their pungent smells, that can be found naturally in foods, such as onions and asparagus. They can sometimes smell like rotten cabbage or garlic. They are also used in a range of products including dietary supplements for poultry and animal feed. Methyl mercaptan is also used in the manufacturing of pesticides and fungicides, pharmaceutical products, resins and many other chemicals.

The distinct smell of mercaptans make them useful as odorants and they help detect the presence of other gases and chemicals, but employers should be aware of the risks that they pose to a workplace as well.


Monitoring exposure to mercaptans

When used in an industrial setting, mercaptans can be highly flammable and over exposure to them can be extremely harmful to health. They can be absorbed quickly through inhalation and minimally through skin and eye exposure. Low levels of exposure can cause irritation of eyes, skin and upper respiratory tract, headaches, vomiting, dizziness. Higher levels of exposure can even cause respiratory paralysis.

There are specific exposure threshold limits for some of the main mercaptans, as laid out by the UK Health and Safety Executive (HSE). They are as below:

  • Methyl mercaptan (methanethiol) - 1.0mg/m3
  • Ethyl mercaptan (ethanethiol) - 1.3mg/m3
  • Butyl mercaptan (butanethiol) – 1.8mg/m3

In a workplace setting, employees should be adequately trained in the safe handling of mercaptans, to limit their exposures and risks. require that employers manage substances which can be harmful to human health. An assessment should be carried out to identify hazardous substances present in the workplace, to determine acceptable precautions, and to note the control measures put in place for the protection of employees.

If COSHH is not properly managed, then employees are at risk of exposure and the dangerous effects these can cause. Improper assessments can lead to a loss in productivity due to illness as well as leave you liable to enforcement action including prosecution under the COSHH regulations.

How we support our clients

Our state-of-the-art laboratory in Manchester provides UKAS accredited analysis of mercaptans, as well as providing the required sampling media.

We use our own in-house method and our ion chromatography provides accurate results, giving our clients peace of mind that their workplace exposure limits for mercaptans are not being exceeded.

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