Bakery Industry: The Risks of Flour Dust

Are your employees at risk of flour dust?

Industrial bakeries and factories handle and process tonnes of flour amongst other ingredients throughout the day and night, seven days a week. In the areas of the factory where any airborne dust particles (including flour) pose a risk to workers, an assessment of their exposure to these particles is a legal requirement under COSHH regulations.

The very finest particles of dust (known as respirable dust) are not visible, so even if you can’t physically see the dust it may still be present in high volume. Visually, if you can see dust particles in shafts of light, then this is an indication that there are high levels of dust in the air, which can pose risk to your workers.

What are the dangers of flour dust?

1. Inhilation of Flour Dust

On the first hand, regular inhalation of fine airborne flour particles can cause ‘White Lung’, also known as ‘Baker’s asthma’, which is a type of occupational asthma. This is a condition that bakery employees can develop after being exposed regularly without the correct controls and preventive measures in place. The HSE statistics reveal that bakery workers are the occupation group at second highest risk of contracting occupational asthma. 

Flour dust contains a number of potential allergens, which have been shown to cause respiratory and dermal sensitisation, leading to occupational asthma and occupational skin disease in bakers. The most important of these are the cereal allergens and the cereal flour protein α – amylase. This material is also a reported cause of protein contact dermatitis in bakers.

Within the factory, there will be areas that would be considered to be higher exposure than others, but employees working in any areas may be at risk. The HSE states that activities around dough breaks which involve the hand throwing of flour are a significant source of direct exposure to flour dust for bakers, particularly in small craft bakeries, and can lead to indirect exposure for other bakery workers through general airborne and floor contamination.

The symptoms of respiratory issues can go unnoticed for a long time, but sudden running or blocked nose, itching eyes and wheezing or whistling chest can indicate the onset of asthma. Repeated bouts of coughing during work can also be a sign that fine particles have entered the lungs. Here is an article which highlights the slow onset of baker’s asthma and how early diagnosis and treatment is so important http://www.hse.gov.uk/asthma/baker.htm

Flour dust has been assigned a Workplace Exposure Limit (WEL) of 10 mg/m³ in EH40/2005 (2nd Edition), as a total inhalable dust. This is defined as the fraction of airborne material which enters the nose and mouth during breathing and is therefore available for deposition in the respiratory tract.

The WEL limit for flour dust also allocates the additional phrase ‘Sen’, which shows that it is known to be a respiratory sensitiser. The HSE (SIM 01/2007/09) have also issued guidance on the WEL for flour dust, which states that “Good control practice can reduce exposure to around 2 mg/m³, based on an 8 hour TWA”.   It is important to note that 2 mg/m³ is an indicative but in many cases achievable value. It should not be regarded as an additional legally binding exposure limit, however there is still a risk of occupational asthma below the level of 2 mg/m³

2. Explosion

Secondly, there is a risk of explosion, explosions and fires within the food industry from combustible materials are a known hazard and they can have devastating and irreversible effects. Examples of explodable dusts in food industries include materials such as: flour, custard powder, instant coffee, sugar, dried milk, potato powder and soup powder.

If a solid substance is finely ground it may ignite more readily or at a lower energy. If any combustible substance is mixed or suspended in air at the correct concentrations and contained in a vessel or building when ignition occurs, then a violent explosion can result.

Ignition energies vary with different substances and for similar substances with differing moisture content and particle size, but may be as low as the static discharge experienced when taking off a synthetic fibre jumper, or as high as that from a ‘fixed flame’ such as a gas fired boiler.

Common processes generating explosible dusts in the food industry include flour and provender milling, sugar grinding, spray drying of milk and instant coffee and conveyance/storage of whole grains and finely divided materials.

Industrial fire and explosion hazards are controlled through the application of DSEAR (the Dangerous Substances and Explosive Atmospheres Regulations) 2002, enforced primarily by HSE and Local Authorities.

COSHH Assessments

COSHH is the law that requires employers to prevent or control substances that are hazardous to health. COSHH Regulation 6 requires that if you employ more than 5 people you will need to have a designated, competent person to carry out the assessment and the findings of the assessment will need to be recorded. Good practice in the control of substances hazardous to health can be encapsulated in the eight generic principles set out below

• Minimise emissions, release and spread
• Consider routes of exposure
• Choose control measure proportionate to the risk
• Choose effective control options
• Personal protective equipment – the final control option
• Review the effectiveness of controls
• Provide information and training
• New measures, new risks

The HSE have these principles in more detail on their website and can be seen here http://www.hse.gov.uk/coshh/detail/goodpractice.htm

The actual monitoring of the level of airborne harmful particles will need to be carried out with specialist air sampling equipment. Read a detailed document of what to expect from a competent monitoring specialist here: http://www.hse.gov.uk/pubns/guidance/g409.pdf

By law your company needs to be having a COSHH assessment by a competent company on a yearly basis.  If this does not take place, you are at risk of prosecution by the HSE.

COSHH Surveillance

As part of your duties as an employer, you must obtain information about employees’ health as well as data on the exposure levels of hazardous substances in their workplace. The objective is to protect them from any potential health risks at work, by early detection of health issues or disease and minimise exposure to harmful substances.

Training for Employees

It is essential that you provide information as well as training and instruction for employees who work with hazardous substances (COSHH Regulation 12 makes this a legal requirement). This must include cleaning and maintenance staff. Your employees need to understand the outcome of your risk assessment and what this means for them. This includes telling them and providing data sheets on the following:

• what the hazards and risks are
• relevant workplace exposure limits
• the results of any monitoring of exposure
• the general results of health surveillance
• procedures for an accident or emergency
• planned future changes in processes or substances and equipment use​

What measures can be taken to prevent exposure ?

There are many changes that can be made to the process of working with flour that will dramatically reduce the levels of airborne dust, here are just some examples:

• Not tipping flour from height when sifting, mixing or weighing
• Flour should be tipped gently and not dumped
• Mixing should be started at a low speed until the flour is combined with the other ingredients
• Consider using an enclosed system to transfer the flour or a separate contained area for sifting, mixing and weighing
• Spilt flour should not be swept up but vacuumed and avoid using compressed airlines for cleaning
• Regular cleaning of high level surfaces where flour dust will have collected
• Careful rolling and disposal of flour sacks, to avoid flattening or folding which would cause a plume of dust
• Empty flour sacks should be stored elsewhere
• Flour and other powder containers to have lids, which should only be removed when necessary
• Implementation of dust extraction equipment or LEV systems in very dusty areas. Fit a manometer or pressure gauge near the extraction point, to show that the extraction is working properly and ensure that the system is on and functioning properly before work commences
• Personal respirators (RPE) should be considered for very dusty tasks in situations where dust extraction is impossible. Remember, RPE is the last line of defence and should ONLY be used ‘in conjunction with other engineering controls’.

What is LEV (local exhaust ventilation)?

Here is a short HSE video explaining LEV and its key components:

In preventing exposure to harmful substances in the workplace, there is a hierarchy of control measures that must be considered, commencing with the elimination or substitution of the hazard or, where these options are not possible, the hazard must be controlled by engineering means.

Local exhaust ventilation (LEV) is one such engineering control measure. LEV is an engineering system designed to reduce employee exposure to airborne contaminants (dust, mist, fume, vapour, gas) in the workplace by capturing the emission at source and transporting it to a safe emission point or to a filter/scrubber.

Employers need to work with designers, suppliers, installers and employees to effectively control exposure to airborne contaminants.

Suppliers must provide LEV that is fit for purpose, is shown to work and continues to work. The employer (the LEV owner) must ensure controls are adequate. Everyone, including suppliers and users of the LEV, must be competent in the use of the LEV system.

How can EFS help you?

Becoming part of your support network, Environmental Filtration Specialists focusses on you, your company and its staff. From the initial assessment through to advice, monitoring, testing, equipment, training and LEV systems, our experienced team can evaluate your individual circumstances and advise you of the best course of action to ensure compliance and keep your workforce safe.

As experts in dust control, EFS have helped many companies to improve their workplace environments. In some cases it can be as simple as process change, or perhaps supplying industrial vacuums or new LEV equipment.