Inhalable Contaminants

Respiratory protection in the workplace includes the safety measures used to protect workers from exposures that can result in serious and harmful health effects – exposures such as dust, diesel fumes, welding fume, silica dust etcetera. These safety measures will involve specific engineering controls (control methods) that are designed to minimise exposure to contaminants, or the use of Respiratory Protective Equipment (RPE) – or a combination of both, dependent on the individual scenario.

Why is respiratory protection important?

If respiratory protection isn’t used, then workers can be exposed to a number of serious health hazards, which are caused by inhaling dust and other contaminants, including but not limited to: welding fumes; gases; solvent vapours; diesel exhaust fumes; legionella and other biological agents; wood dust; silica dust; asbestos; and isocyanates, epoxy and other resin vapours and mists.

The exposures listed above pose serious risks to workers’ health, and can result in lung diseases which are debilitating, irreversible, life-limiting, and in some cases – fatal. These diseases include: lung cancer; pulmonary fibrosis; asthma; pulmonary oedema; pneumonia; and chronic obstructive pulmonary disease (COPD) – conditions include chronic bronchitis and emphysema.

“workplace exposures such as dust, diesel fumes, welding fumes, silica dust etc. can result in serious and harmful health effects”

In the construction industry, workers are 100 times more likely to die from an occupational disease than a workplace accident. A further example of workers at risk of exposure are welders. Welding is one of the top 10 causes of workrelated cancer, causing an estimated 150 deaths a year in the UK. In addition to COPD, welding is associated with numerous serious health conditions such as asthma; metal fume fever; effects on the nervous system; reduced lung function; and short-term irritation of the throat and lungs.

Who should use respiratory protection?

In simple terms, anyone who is potentially at risk of inhaling contaminants should use the appropriate respiratory protection. Whilst vital for any workplace where there is a risk of exposure, respiratory protection is especially relevant for many employees in the construction industry, and also in manufacturing, e.g. welders – for the reasons outlined in the previous section.

If in any doubt about whether they are at risk from exposures, employees should seek guidance from their health and safety manager, or the designated person within their company who has responsibility for health and safety.

Using control methods

Key to ensuring the best protection for the affected workers, is recognising the hazards and evaluating the risks. Also, rather than simply opting for the easy choice of RPE, it’s vital that consideration is firstly given to introducing other relevant or additional control methods. Once the workplace health hazards and resulting risks have been evaluated, it’s then possible to determine the controls required.

“it’s vital to remember: a good control method becomes a poor one if it’s broken or not used properly”

Examples of control method options could be: sourcing alternative products and materials to those currently used; implementing engineering controls, such as dust extraction tools and ventilation; changing work methods and habits; and segregating work areas.

Evaluating risks is critical to the process of controlling exposures, because there are numerous respiratory hazards that cannot be seen by the naked eye. This means that many ill health effects don’t appear until many years later. Often, published workplace exposure limits and guidance surrounding known hazards can provide the information needed in order to assess the health risks. Sometimes, however, only specialist exposure monitoring techniques – like air or biological monitoring – can determine the level of risk for particular workers to particular diseases.

For welders in particular, the health risks can be many and serious, and these risks have been outlined earlier in this article. The following statistics outline the extent of the risk potential, and underscore why it’s critical to evaluate these risks and ensure the correct control methods are implemented: it is estimated there are 190,000 workers in the UK who weld, comprised of around 73,000 professional skilled welders – and many other unskilled or semi-skilled welders who carry out this activity as part of their job. Health hazards specifically associated with welding are: fume; gases; UV radiation (which can affect both the eyes and skin). However, control measures are available, and it’s important to ensure the right controls are used – there’s not just one solution that will be effective in all cases. Some of the control measures available are: local extraction; welding benches; and on-gun extraction for MIG welding. It’s absolutely imperative, however, that the risk is evaluated for each type of activity, in order that the correct control is selected. For all activities, and welding is no exception, RPE should always be the last resort, but it will be the most appropriate control for some types of work, particularly very large fabrications where the use of local extraction is impracticable. Powered devices that are built into the welding visor are likely to be most effective for common situations.

Last but not least, also critical to ensuring the success of control methods is training and communication, which should include: supervision; maintenance and testing of controls; and ongoing monitoring. It’s vital to remember: a good control method becomes a poor one if it’s broken or not used properly.

Using RPE

The most common type of RPE is a face mask, used to protect workers from inhaling hazardous substances. We have discussed earlier why other control methods are preferable to RPE. There are a number of reasons why Personal Protective Equipment (PPE), including RPE, is considered “the last resort”.

They include:

• It only protects the wearer, i.e. it doesn’t protect others in the vicinity – who may not be wearing protection
• The hazard is still present – the problem hasn’t been solved
• If incorrectly used, the wearer may not receive adequate protection (fails to danger)
• People often believe that it is more effective than it really is – which means it can give a false sense of security

However, there are many circumstances where RPE is likely to be the most practicable option. These include:

• Where other methods of control are not technically feasible or are prohibitively expensive
• Where exposure only occurs occasionally, e.g. some maintenance operations; intermittent exposure during shift work
• During emergencies, e.g. spillages, gas leaks etc.
• Where it is a secondary control measure

“in the construction industry, workers are 100 times more likely to die from an occupational disease than a workplace accident”

Where RPE is being used to control exposure, it is important that the correct device is used. It needs to be:

• Adequate – correct for the hazard
• Suitable – matched to the wearer, task and environment

Additional important notes on respirator use:

• Air-supplied devices provide air from an uncontaminated source (cylinder or airline) and will be needed in high risk situations such as entry into confined spaces where hazardous gases may be present, or where there is a risk of oxygen deficiency
• For most situations, filter respirators will be adequate. With these devices, air is drawn through a filter which removes the contaminants: it is important to ensure that the correct filter is fitted. The device cannot be used unless a safe level of oxygen can be guaranteed
• When using a filter respirator, it is essential that the correct filter is fitted

“in the construction industry, workers are 100 times more likely to die from an occupational disease than a workplace accident”

The following table gives some guidance for some common contaminants, but it doesn’t cover all situations, so if you’re unsure what filter you need, then do obtain specialist advice from a qualified professional.

Combination filters are also available, and these can provide protection against more than one contaminant. They have the appropriate combination of letter and colour codes marked on the filter.

The level of protection provided depends on the type of face piece and filter. With dust and other particles (e.g. welding fume) the same filter will provide a higher level of protection when fitted in a full-face mask than in a half mask. With gases and vapours, the protection factor will be a maximum of 10, whatever mask is used.

The protection factor indicates by how much the contaminant concentration is reduced. For example, a protection factor of 10 means that the concentration inside the face piece will be one tenth of the concentration outside the mask. Similarly, a protection factor of 20 means that the concentration inside the face piece will be one 20th of the concentration outside the mask.

Once a selection of devices has been found that will give adequate protection, consideration needs to be given to which is the most suitable for the particular circumstances, taking into account compatibility with:

• The user
• The task being carried out
• The working environment
• Other PPE that needs to be worn

One very important factor when selecting suitable RPE is facial hair. A good face seal cannot be achieved where workers have a beard, or even stubble. Tight fitting devices can only be used if the user is clean shaven. If not, then a loose-fitting device, such as a hood or visor, will need to be worn.

Good management of RPE is important to ensure that it is effective in protecting the user.

Factors to consider include:

• Face fit testing – with tight fitting devices this should be carried out before the mask is first used
• Ensuring that the masks are readily available to users
• Making sure re-usable devices are maintained, tested and cleaned regularly
• Ensuring that disposable devices are disposed of at the end of the day – they are not designed to be re-used
• For devices that are designed to be re-used, proper storage facilities should be provided to ensure the device doesn’t become contaminated

Information, instruction and training on RPE should be provided for: everyone who uses RPE; their supervisors; any other staff directly involved, e.g. staff likely to be exposed to contaminants.

The training should cover:

• Why the RPE is needed
• How to fit and use it correctly
• How to look after it – testing, storage etc.
• The potential consequences of incorrect use

Respiratory protection de-mystified

Clearly, respiratory protection is not only a highly important subject area, but is also a big area to understand, involving many considerations and decisions – so professional advice and guidance will often be needed. However, free, expert advice is available: BOHS, the Chartered Society for Worker Health Protection, has developed two campaigns to help protect employees from exposures in the workplace: Breathe Freely in Construction; and Breathe Freely in Manufacturing. Information is available to download from these web-based information hubs, which act as a centre of excellence on exposure control. The information includes: guidance materials; good practice case studies; trade fact sheets – including one for RPE; toolkits; and external links to other relevant information. This is just a small selection of the help available, and BOHS invites you to visit these websites to find out exactly what materials are on offer.

References

• Breathe Freely in Construction
• Breathe Freely in Manufacturing