The grainy truth about occupational asthma

Every year in the UK alone there are an estimated 200-300 new cases of occupational asthma seen by chest physicians, as reported by the HSE, a figure which has remained largely unchanged for 10 years. In addition, there are currently an estimated 18,000 new cases of self-reported ‘breathing or lung problems’ caused or made worse by work every year in the UK, according to the 2017 Labour Force Survey, as reported by the HSE.

One of the causes, flour dust can, if handled badly, be extremely dangerous to lung health. It is one of the most cited causes of occupational asthma by chest physicians, second only to isocyanates.

So what is flour dust? Simply, it is finely ground particles of cereals or pulses, including contaminants. It is an example of a substance, which when inhaled can cause occupational asthma, called ‘respiratory sensitisers’ or asthmagens.

The health effects of inhaling flour dust depend on the concentration of the airborne flour and how long you've been exposed to it. Frequent low-level exposure might not create symptoms for up to 30 years.

Workers in the baking industry constantly handle flour. Some of the activities that create high concentrations of airborne flour dust include:

  • Loading flour and other ingredients into mixers
  • Dusting flour onto baking surfaces
  • Dry sweeping flour dust from shelving or the floor
  • Disposing of empty flour bags

How to reduce the risks

The most effective way to reduce the risk of exposure to flour dust is to eliminate the source of exposure. But if that's not possible, there are other risk controls to use. Some methods for doing this are to use:

  • Fully automated bulk ingredient handling systems from silos
  • Automatic dosing from bulk / tote bags
  • Local exhaust ventilation (LEV)
  • PPE - masks are essential. Some operators prefer air fed masks as the airflow is fresh and breathing resistance is reduced and the combined, integrated protection
  • offers respiratory, head, face and eye coverage offers higher protection factors
  • Consider whether the ingredients are handled in the best way. Simply changes can have dramatic effects - changing from a round sieve to a conical sieve, for
  • example, can reduce respiratory sensitisers by up to 38%

Pamela Brown, Former IOSH Chair of Food and Drink Group and member of the Federation of Bakers


Disclaimer: The information and opinions expressed on this webpage are those of the author and not necessarily those of the Institution of Occupational Safety and Health (IOSH).