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Prevention is key

10 August 2021

George Elliott provides an insight into how to protect your workers from Respirable Crystalline Silica.

Statistics from the Health and Safety Executive (HSE) for 2019/20 show that there were 111 deaths in the workplace in Great Britain1. Falls from height, moving vehicles and moving machinery are the main reasons for these deaths. While this figure makes for difficult reading, there are 12,000 lung disease deaths each year linked to past exposures at work to chemicals or dusts, which really highlights the importance of controlling respiratory hazards. Although there are limited, recent, figures regarding respirable crystalline silica, the last HSE figures come from 2005 - the data suggests there were over 500 construction worker deaths from long-latency silica exposure.

Education is certainly improving regarding respirable crystalline silica and employers and employees are more aware of the dangers of this airborne hazard. When (construction) materials containing silica are cut or crushed, tiny particles of crystalline silica are released. These are known as respirable crystalline silica – these particles may penetrate deep into the lungs and cause significant damage including scarring of the lungs. These tiny jagged particles are so small that they can't be seen by the eye and without adequate control measures may bypass our body's natural defences.

The effects of prolonged exposure to respirable crystalline silica can be silicosis, lung cancer and COPD. While these are irreversible, incurable and all potentially fatal they are avoidable with the correct control measures.

When it comes to controlling silica hazards following the Hierarchy of Controls (HoC) is key. HoC considerations should always start with asking whether the silica hazard(s) can be eliminated, or if not can they be substituted. However, this is not always possible. Engineering controls should also play their part – for example, using on tool extraction to remove dust at source or using water to dampen down the dust. Administration considerations can aid with reducing the number of people that are in the area where the silica producing activities are taking place. 

When it comes to the final control measure of the HoC, PPE, the HSE guidance states that you need to reduce exposure as far as reasonably practicable – even with dust extraction or water suppression individuals still need to wear Respiratory Protective Equipment. This should have an assigned protection factor (APF) of at least 20. An APF 20 could be provided by a Disposable Respirator (FFP3), Reusable Respirator with P3 filters or alternatively a TH2 Powered Air System (note a TH3 Powered Air System can provide an APF40 which may be required for certain activities). 

An organisation that is very useful to turn to for HoC information is The Construction Dust Partnership (CDP), which raises awareness about lung diseases related to hazardous workplace dust and promotes appropriate controls to prevent these diseases. They have excellent resources and case studies for employers and employees when it comes to implementing HoC. CDP have a dedicate website for their website and also an active LinkedIn account which posts topical content on a regular basis. 

Focus on protection

Face coverings are now commonly worn by the UK population, but these are intended to help protect the work environment from substances expelled by the wearer and do not offer respiratory protection. Respirators are worn to protect the wearer from substances in the work environment.

When it comes to respirable crystalline silica , we know that the minimum protection is going to be an APF of 20. You need to make sure that what you are offering your employees is adequate. Simultaneously, you need to make sure that the RPE is also suitable for the individual wearing it. You need to consider an individual's own needs, for example if they have facial hair or a pre-existing respiratory condition.

Disposable respirators come in a broad range of shapes, sizes and materials and they filter out particulate hazards. If they are not rated to be re-used (denoted by NR marking), they need to be thrown away safely after use. Reusable respirators need to be cleaned after each use and need to be maintained with regular changing of filters.

Tight fitting disposable respirators or reusable respirators should not be worn with facial hair that can affect the seal to the face. Facial hair between the face and the seal of the respirator can negatively influence the fit and therefore protection provided. In addition, tight fitting respirators need to be face-fit-tested to validate that they fit the wearer - this is the responsibility of the employer. Further information regarding face fit testing can be found via the HSE’s guidance document INDG 479 and in addition the British Safety Industry Federations’ companion guides. 

Powered air solutions connected to loose fitted headtops do not need to be face-fit-tested. They are powered by a battery and supplies large volumes of filtered air to the headtop. These loose fitting devices could be considered for those with degrees of facial hair. In addition, as they are loose fitting, they do not need to be face fit tested. Often the devices can provide higher levels of respiratory protection (up to an APF 40). are powered by a battery and supplies large volumes of filtered air to the headtop.

Care and maintenance

It is so important that the RPE is cared for and you need to speak to your manufacturer of choice – whoever you are buying your RPE from – for them to give you the specifics on the care and maintenance of your equipment.

If you are keeping any respiratory protection for more than a month the HSE require that you should be conducting care and maintenance and you should also record the care and maintenance that is conducted. Further information on the requirements can be found via the HSE document HSG 53. 

This is a very brief write up of a webinar containing much more information. Please watch it on demand, where you will also be able to listen to questions from the viewers and answers from George Elliott.https://events.streamgo.live/Silica-dust-in-construction/live


1 https://www.hse.gov.uk/statistics/fatals.htm

George Elliott is senior application engineer UK&I for 3M Personal Safety Division. For more information, visit www.mmm.com