Grain dust

What is grain dust?

Grain dust is the dust produced from the harvesting, drying, handling, storage or processing of barley, wheat, oats, maize or rye and includes any contaminants or additives within the dust (eg. bacteria, endotoxin, fungal spores, insects and insect debris, pesticide residues).

Health risks are also likely to arise from exposure to dusts produced by other types of grain, eg. rice, sorghum, pulses (such as soya bean), peas and various oilseeds (such as rapeseed).

Does this concern me?

Respiratory disease (a disease affecting our lungs and breathing tubes) is a major occupational health risk, for example, in agriculture the number of occupational asthma cases is double the national average. Studies have shown that workers exposures to grain dust can be substantial.

Workers with occupational respiratory disease may develop permanent breathing problems, becoming disabled, and unable to work. This not only affects individual workers, but has wider cost implications for employers and the grain industry as a whole.

What does the law say?

The law requires employers to adequately control exposure to materials in the workplace that cause ill health. This includes controlling exposure to grain dust. Employers and employees need to comply with the Control of Substances Hazardous to Health Regulations 2002 (as amended) (COSHH). They require employers to:

  • assess risks;
  • provide adequate control measures and make sure they are used and maintained;
  • provide information, instruction and training; and
  • provide health surveillance.

Where might you be exposed to grain dust?

Vast quantities of grains are imported, exported, produced and used in Britain. Grains pass through a large number of handling operations and the generation of dust is therefore widespread.

Industry sectors:

  • agriculture;
  • flour mills and food factories;
  • animal feed mills, feed blenders and feed compounders;
  • maltings, breweries and distilleries;
  • docks and grain terminals;
  • commercial stores; and
  • transportation of grain.

Processes that create grain dust include:

  • harvesting grain and transferring grain from combines into trailers;
  • cleaning, dressing and drying grain;
  • moving grain about in a grain store;
  • transferring grain in or out of grain stores or terminals;
  • milling and mixing dry grain;
  • feeding dry milled grain;
  • maintenance of plant and equipment;
  • cleaning of buildings, vehicles, plant and equipment using compressed air or by manual/mechanical sweeping; and
  • silo cleaning.

Respiratory disease

Our respiratory or breathing system includes the mouth, nose, lungs and the tubes that connect them. Occupational respiratory disease is a medical term used to describe diseases caused by, or made worse by, something you breathe in while at work, eg grain dust.

Eye and skin effects

Eye and skin irritation are frequent reactions to grain dust exposure and include symptoms such as:

  • conjunctivitis (watery or prickly eyes);
  • itchy skin and skin rashes.

Respiratory effects

The possible ill health outcomes are:

  • rhinitis (runny or stuffy nose);
  • coughing and breathing difficulties (see asthma and COPD);
  • asthma (attacks of coughing, wheezing and chest tightness);
  • chronic bronchitis (cough and phlegm production usually in winter months and associated with     smoking);
  • COPD – chronic obstructive pulmonary disease (a longer-term illness that makes breathing progressively difficult, includes chronic bronchitis and chronic asthma);
  • extrinsic allergic alveolitis, for example farmer's lung (fever, cough, increasing shortness of breath, muscle/joint pains and weight loss);
  • organic dust toxic syndrome, for example grain fever (a sudden onset, short-lived, 'flu-like' illness with fever and often associated with cough and chest discomfort).

Occupational asthma

Some occupational respiratory diseases affect the tubes that carry air in and out of the lungs (our airways). Occupational asthma is an example of this sort of problem. It is caused by an allergy to something in the workplace, eg grain dust. This type of allergy usually takes several months or even years to develop, and may also cause eye and nasal symptoms at work.

Occupational asthma causes the airways to swell and tighten; leading to symptoms of coughing, wheezing, chest tightness or breathlessness at or after work. If these symptoms are better on non-work days (like weekends, rest days or holidays) then occupational asthma needs to be strongly considered.

As well as causing asthma, working with grain dusts can also worsen symptoms in people who already have asthma. It is much better to prevent respiratory disease by using good working practices.

Health surveillance

If you suspect you may have a respiratory problem, report your work-related symptoms to your employer. Grain dust is a respiratory sensitiser (asthmagen) and it is essential that health surveillance is undertaken to enquire positively about any early symptoms of ill health. Employers have a legal duty to carry out health surveillance that is based on risk under COSHH.

The objectives of health surveillance are to:

  • protect the health of individual workers by detecting, as early as possible, symptoms that may be caused by exposure to grain dust;
  • help evaluate the effectiveness of measures taken to control exposure; and
  • collect information to update knowledge of health hazards in the workplace.

Decisions on the appropriate form of health surveillance may require the advice of an occupational health professional. The precise form of health surveillance will depend on the particular circumstances of exposure (level, frequency and duration) identified by the risk assessment.

HSE guidance EH66 on grain dust provides further information on health surveillance.

HSE have summarised the evidence about respiratory disease caused by exposure to grain dust in research report 'Risks to respiratory health in the UK grain industry'.

What should I do about it?

If you cannot avoid exposure to grain dust then you must put in place appropriate control measures including one or more of the following:

  • changing processes and activities to reduce grain dust at source;
  • segregate processes from exposed workers;
  • enclosure of the process;
  • local exhaust ventilation (LEV);
  • good general ventilation;
  • organising work to minimise the number of people exposed and the duration, frequency and level of exposure;
  • proper handling of materials;
  • good maintenance of plant and equipment;
  • good housekeeping (don't use a brush or compressed air, and never use compressed air to remove dust from clothing); and
  • informing and training employees on the use of control measures;

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