Grain Dust Exposure Testing: Health Effects and Ensuring Safety

Grain dust exposure is a significant concern within the agricultural and grain processing industries. The fine dust particles generated during the handling and processing of grains can pose serious health risks to workers, including many respiratory health conditions such as occupational asthma, rhinitis, COPD, organic dust toxic syndrome (ODTS) and farmer’s lung. 

It is imperative for businesses within industries associated with grains to ensure that adequate and effective dust control measures and potential grain dust exposure testing are in place to help prevent such health conditions from developing for the safety of employees and compliance with UK Health and Safety Legislation. 

In this article, we will explore what grain dust is, activities likely to generate grain dust, potential health effects from exposure to grain dust and when grain dust exposure testing may be required. We will also discuss the current UK regulations relating to grain dust and methods to assess the risks and control its exposure effectively, ensuring a safe and compliant workplace. 


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What Is Grain Dust?

The grain industry, including the diverse and wide range of activities involved, such as the growing, farming, harvesting, handling, drying, storage, processing, and distribution of grain, has been a vital part of the agricultural sector throughout the UK for centuries. 

Grain is the seed of cereal crops and comprises a cellulose-based seed coating and carbohydrate-based interior. The processing stage of grain and its derivatives includes milling and malting. The handling stage includes loading, unloading, packaging, transport, and storage operations. 

Grain dust, which is a byproduct composed of fine particles released during these tasks, poses significant risks to workforces involved in these agricultural processes, transport and related industries within the food and drink industry. 

Grain dust particles coming from grains such as wheat, oats, maize, barley, rye, and corn can also become contaminated with other additives and residues resulting in the grain dust becoming a mixture of differing elements and contaminants. The type of contaminants present will depend on the origin of the grain and can include: 

  • Bacteria 
  • Fungal spores 
  • Actinomycetes and other similar bacteria 
  • Microbial toxins such as endotoxins and mycotoxins 
  • Insects and insect parts 
  • Storage mites and their excreta 
  • Weevils and their excreta 
  • Animal hair 
  • Feathers from pigeon infestation 
  • Excreta from insects/animals 
  • Pollen 
  • Silica and Silica Dust 
  • Soil particles 
  • Fungicide, pesticide, and fertiliser residues 
  • Plant debris other than grains. 

The HSE Guidance Note EH66 (Third Edition) has guidance for grain dust for other types of grain as well, such as rice, sorghum, pulses, peas, and various oil seeds. 

It is estimated that within the UK in 2024, there are more than 465,000 people working within the industry, all of which will be exposed to grain dust in some way during their daily operations. 

Therefore, proper management, control and testing for grain dust exposure are essential to protect these workers. 


Grain Dust Health Effects and Hazards

Grain dust exposure can cause occupational asthma and has been assigned a ‘Sen’ notation within HSE document EH40/2005 Fourth Edition 2020 indicating it is a respiratory sensitiser.  

Studies have shown that workers’ exposures to grain dust can be substantial. 

If an individual develops occupational asthma, exposure to low levels of grain dust could trigger an asthmatic attack; possibly resulting in the worker needing to change profession. In addition, some people develop sensitivity, which means their symptoms persist long after exposure ends. Symptoms can be delayed which can lead to a failure to make the connection with their work. 

The HSE have outlined possible ill-health outcomes such as: 

  • Rhinitis (runny or stuffy nose) 
  • Coughing and breathing difficulties 
  • Asthma (attacks of coughing, wheezing and chest tightness) 
  • Chronic Bronchitis (cough and phlegm production usually in winter months and is also associated with smoking) 
  • Chronic Obstructive Pulmonary Disease (COPD) (a longer-term illness that makes breathing progressively difficult, and includes chronic bronchitis and chronic asthma) 
  • Farmer’s Lung, also known as extrinsic allergic alveolitis, for example (fever, cough, increasing shortness of breath, muscle/joint pains, and weight loss) 
  • Grain Fever, also known as organic dust toxic syndrome (ODTS), (a sudden onset, short-lived, ‘flu-like’ illness with fever and often associated with cough and chest 

Due to the potential make up of grain dust it may cause a variety of health effects. There is evidence that negative health effects can be caused not only from the dust of the grain but also potentially from the other plant and animal contaminants. For example, asthma, reported among workers exposed to grain dust, is often caused by sensitisation to storage mites. 

Grain dust hazards may also be affected by how the grain is stored; exposure to grain stored in a damp environment (i.e. mouldy grain) may lead to farmer’s lung from exposure to a wide variety of antigens or bacterial and fungal species in the mould. 

Eye and skin irritation are frequent reactions to grain dust exposure and include symptoms such as conjunctivitis (watery or prickly eyes) and itchy skin and skin rashes. 

Businesses should also be aware of the huge and real risk of explosions caused by grain dusts or products made by milling grains such as Flour Dust. These risks can be assessed by trained fire risk professionals who can complete a DSEAR Risk Assessment


Who May Require Grain Dust Exposure Testing?

The UK is a significant producer of grains, with The Department for Environment, Food & Rural Affairs (DEFRA) estimating an annual grain production of over 23 million tonnes just from wheat, barley, and oats alone.  

This doesn’t include the average 6 million tonnes imported into Britain annually.  

Due to grains passing through a large number of handling operations like harvesting, drying, milling, cleaning, and transportation the generation of dust is therefore widespread, reflecting the overall importance of grain dust exposure throughout the agricultural sector. 

Some of the main industry sectors affected by grain dust exposure include: 

  • Agriculture/ Farming 
  • Animal feed mills 
  • Breweries 
  • Commercial stores 
  • Distilleries 
  • Docks 
  • Flour mills 
  • Food factories 
  • Grain terminals 


What Are The Grain Dust Exposure Limits?

Grain dust in the UK is regulated by The Health and Safety Executive (HSE) under the Control of Substances Hazardous to Health (COSHH) Regulations 2002.  

The HSE sets Workplace Exposure Limits (WELs) for hazardous substances in order to protect worker health. 

Currently, grain dust has a workplace exposure limit (WEL) of 10 mg.m-3 8hour (Time-Weighted Average) 

However, due to grain dust being classified as a sensitiser and the lack of scientific knowledge regarding which grain dust will cause asthma, exposure must be as low as reasonably practicable (ALARP). 


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When Is Grain Dust Exposure Testing Required?

Grain dust exposure testing is a crucial aspect of maintaining workplace safety and regulatory compliance in the grain industry.  

Testing is required in several scenarios to ensure that dust levels remain within safe limits and to protect workers from potential health hazards. We have outlined some of the key instances when grain dust exposure testing is necessary: 


For Regulatory Compliance 

The COSHH Regulations in the UK mandate that employers assess risk and, if deemed to be required, monitor and control dust exposure to protect worker health.  

Testing is required to meet current legal requirements and ensure grain dust exposure levels comply with the WELs set by the HSE in order to protect worker health and to provide documented evidence of such compliance for regulatory inspections and audits. 

After Process Changes 

If any modifications to handling or processing techniques are implemented, these can affect the amount of dust generated.  

Grain dust exposure testing is required after: 

  • Installing new machinery or existing equipment is upgraded. 
  • Processing methods have been changed, such as switching from manual to automated systems. 
  • Operational changes, such as altering the way grain is stored, handled, or transported. 

During High-Risk Periods 

Certain periods may pose a higher risk of grain dust exposure, necessitating increased testing. 

Periods such as harvest season where increased handling and processing of grains take place or during dry weather conditions when higher dust levels may be present due to increased airborne particles. 

For Incident Response 

Following incidents such as spillages where substantial amounts of dust is released into the air or the malfunction of dust control systems, such as filtration units or local exhaust ventilation (LEV) systems that can spike dust levels.  

Immediate testing is then essential to assess the risks and implement corrective measures.  

After Health Surveillance Triggers 

If workers report symptoms of respiratory issues or other health problems associated with grain dust exposure, targeted testing will be required to identify the exposure levels and determine if workplace dust levels are contributing to such health problems. 

Immediate steps will then need to be taken to reduce exposure and further protect worker health. 

New Facility Setups 

When establishing new storage facilities or grain processes, initial grain dust exposure testing is necessary to establish baseline dust levels to compare against future measurements and to ensure dust control systems are in place and effective from the start. 

Routine Monitoring 

Regular workplace exposure monitoring of grain dust exposure is essential to ensure a safe working environment.  

Routine testing helps with detecting any gradual increases in dust levels over time, which could indicate changes in processes or control measures and confirm that dust control measures are consistently effective and that grain dust exposure levels remain within safe limits. 


Assessing the Risk of Grain Dust

All employers have a legal obligation to prevent and reduce grain dust exposure of their employees to as low as reasonably practicable. 

COSHH requires employers to carry out an assessment of the risks to the health of employees which may be caused by hazardous substances present in the workplace; this includes grain dust. 

An assessment is required wherever exposure to grain dust is likely to occur. When making the assessment, you should consider all aspects of the handling and processing of grain. This may involve carrying out measurements to determine personal exposure to grain dust by air sampling. 

In order to assess these risks to employee health, employers must identify all of the potential sources of exposure to which employees are likely to be exposed, and for how long. Including the individual components or additives to grain, such as pesticides used during storage and medicated products used in animal feed production. 

“Visible dust clouds, layers of dust on floors, ledges and equipment, or dust leaking from machinery would indicate that there is a problem requiring action to be taken to reduce dust at source. Remember, you can’t usually see the very fine dust that you can breathe into the deep recesses of your lungs, and which will cause most harm.” – HSE Guidance Note EH66 (Third Edition) 

A Dust Lamp Survey can be completed to visualise airborne levels and potential dust sources. 

It is also important to inform employees and safety representatives about the risks identified by the risk assessment. 


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Grain Dust Exposure Control Methods

Where it is not reasonably practicable to prevent exposure to grain dust, employers should follow the principles of good practice to control exposure to grain dust.  

You can control grain dust exposure by a combination of methods, which may include: 

  • Changing processes and activities to reduce grain dust at source 
  • Enclosing the process 
  • Ensuring good general ventilation 
  • Using local exhaust ventilation (LEV) 
  • Ensuring proper handling of materials 
  • Organising the work to minimise the number of people exposed and the duration, frequency, and level of exposure 
  • Ensuring good maintenance of plant and equipment 
  • Following good housekeeping principles (not using a brush or compressed air to remove dust from clothing) 
  • Informing and training employees about the use of control measures 


Ensuring Regulatory Compliance

In order to ensure compliance with current UK COSHH Regulations for grain dust, all exposure control measures should be in place and be used correctly by all workers, with them also being aware of the fault reporting procedures to ensure swift remedial works can be carried out. 

Correct instruction and training should be supplied to all employees potentially exposed to grain dust and all control measures cleaned and maintained regularly. 

Personal grain dust exposure can be monitored though air sampling / Occupational Exposure Monitoring completed by a professional and competent occupational hygienist, the results of which can be directly compared to the grain dust WEL. 

Health surveillance should also be implemented, including pre-employment screening and questionnaires during employment to be completed at 6 weeks and 12 weeks after their start date and then on an annual basis (as a minimum). The results of these should then be analysed by a professional occupational health worker who can advise on further action if needed including lung function tests. 

The Thorough Examination and Testing (TExT) of LEV Systems should also be undertaken to any /all installed systems for the purpose of exposure reduction and control. 


Your Occupational Exposure Testing Experts

ECL (Environmental Compliance Ltd) specialise in a multitude of Occupational Hygiene Services and are experts in managing grain dust exposure in the workplace. Our comprehensive services include: 

  • Workplace Exposure Assessments: Conducting thorough evaluations of your facility to identify high-risk areas and using monitoring equipment to measure dust levels accurately. 
  • Risk Analysis: Identifying high-risk activities and providing tailored solutions to mitigate dust exposure. 
  • Compliance Support: Helping you meet HSE regulations and maintain a safe working environment. 
  • Detailed Reporting: Providing clear and concise reports with actionable recommendations to improve your dust control measures. 
  • Ongoing Support: Offering continuous monitoring services and expert advice to maintain a safe working environment. 
  • Local Exhaust Ventilation Testing: Conducting thorough examinations and testing of your extraction systems to ensure employee exposure is reduced and controlled. 

Our team of expert occupational hygienists are dedicated to ensuring that your workplace is not only compliant but also safe and healthy for all employees. Contact us today to learn more about our grain dust exposure testing service and how we can help your business. 

By prioritising grain dust exposure testing, you are safeguarding your workforce, enhancing operational efficiency, and ensuring regulatory compliance.  

Call us on 01443 801215 or fill out our Enquiry Form for any queries regarding COSHH Air Monitoring, Vibration Assessments, Workplace Noise Assessments or any of our many other Air Quality, Environmental Monitoring, Consultancy or Occupational Hygiene services.