Created with Snap
  • Latest Issue
  • Trending
  • Press
  • Videos
  • Events

Death by Dust

Published: 22nd Jul 2015

Mention health and safety in, say, construction or aggregates and many of you would no doubt think of accident prevention. It is understandable – accidents are immediate, often devastating in their impact and can bring progress to a halt on important projects.

Yet this paints only a fraction of the picture in terms of the challenges we face in keeping people safe from harm at work in the Middle East. Globally, there are 2.3 million work-related deaths a year. Two million are caused by ill health, with just 0.3 million down to workplace accidents.

This is why organisations are dedicating more time and resources to raising awareness of occupational health issues and why this year IOSH is turning the spotlight on the carcinogen respirable crystalline silica, as part of its No Time to Lose campaign to beat occupational cancers.

For the Middle East, this focus is timely. Stimulated by infrastructure development projects, such as the much-publicised 2,200km rail network, and strong growth in general economic activity, business is thriving in those industries in the region for which exposure to respirable crystalline silica is a real risk.

Aggregates, construction, foundries, cement manufacture and stone working are all areas of industry in the Middle East that must deal day-to-day with silica dust.

What are the risks with silica?

Inhalation of very small respirable crystalline silica particles puts workers at risk of silicosis, lung cancer, chronic obstructive pulmonary disease (COPD), and kidney disease. One of the main problems is that once silica is inhaled into the lungs it can remain there. This is because the body’s normal process for clearing the respiratory system does not work on this chemical compound.

Usually when dust is inhaled it is either removed by small hairs called cilia or absorbed in mucus which can then be coughed up, but this does not happen to silica – it remains in the lung where it can cause damage. Respirable crystalline silica is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC), part of the World Health Organization. It is treated as a definite cause of cancer in humans.

Although silica dust is very visible, its harmful effects might take a long time to develop into an illness, by which time the damage has been done. The Health and Safety Executive (HSE) in the United Kingdom has estimated that in order to prevent lung diseases being caused by silica, workers should breathe in no more silica dust than when swept together would form a clump about half the size of a grain of rice. This is a very small amount of silica, especially when you see the plumes and clouds of silica dust that can be created in some industries such as construction, aggregates and stone working.

Tackling the problem

First of all you need to assess the situation. Look at your process where silica dust can be produced. Determine which and how many workers are being exposed and what work tasks they are doing, as well as the equipment they are using, that could be causing the exposure. You need to think about the frequency, length of time and where they are carrying out these tasks. All of these things will have an impact on the amount of exposure and the controls that might need to be used.

How many and which workers are being exposed might affect whether you need to look at collective protection controls such as extraction or suppression, or individual protection such as respiratory protection. If the task is being carried out frequently and for long periods of time then the amount of exposure and harm could be increased, so you might need to consider ways of working that reduce the frequency and length of an activity. This could include designing and using material already cut to size. If the work is being done in an enclosed area then the silica dust can build up, increasing the exposure. You should not just rely on natural ventilation if the work is outside, as you can still get harmful levels of silica dust exposure outside, especially if powered tools are used as these can generate more dust than manual or lower powered tools.

So to control the risks we should use the universal safety principles of:

• Elimination • Substitution • Reduction • Prevention

Not all of the above would be suitable controls depending on the task and nature of the work, but one or more of the principle controls should be used. The least effective control would be personal protective equipment.

Elimination could mean using and ordering the right sized material or using a design that reduces the amount of cutting, for example, different types of joints, fixings or pre-moulded material. It could also mean the use of silica-free material if possible. Substitution could mean the use of material with less silica or replacing high powered tools for lower powered tools; for example, using block splitters for block work instead of cutting equipment.

Reduction is probably one of the most widely used principles. It is used to lessen silica dust exposure mainly through either suppression systems or extraction systems. Suppression uses water to dampen down the dust clouds, but it isn’t effective to just wet the material before work starts – it requires water to be supplied during the whole operation. Water suppression can be supplied directly to cutting equipment. Extraction systems remove the silica dust through local exhaust ventilation systems. These again are usually connected directly to the cutting equipment to remove the dust at source, rather than trying to extract a cloud of dust once it has formed. Some large automated machines have a combination of controls, although it is difficult to combine water suppression with extraction. Some of these processes have brushes and shields to capture the dust that is then washed down during the process with water. Again, some large pieces of equipment have a combination of water suppression and matting to capture the silica dust that is generated. General mechanical ventilation can also reduce build-up and exposure to silica dust, but be aware of where the extracted air is going and make sure it is not exposing other people to the silica dust.

Another way of reducing exposure is segregation, in which you section off (where possible) areas that have the highest levels of silica dust production from employees. If solid partitions are not possible then sheets or shrouds could be used if suitable.

When the other controls are not possible, practicable, suitable or sufficient, personal protection has to be used in the form of respiratory protective equipment (RPE). When RPE is used you will have to make sure that the RPE is suitable for the amount and type of dust and suitable for the employees and the tasks.

RPE has an assigned protection factor (APF). This indicates the amount of protection the wearer has when using it properly. The general level used for construction dust is an APF of 20, which means that if the wearer has the RPE on correctly he or she will only breathe one twentieth of the dust in the air. If RPE is to be effective in its use it needs to fit the user – simple face fit tests can be employed to ensure this. If employees are not clean shaven then the APF will be reduced.

Other things to consider are that disposable or ‘half’ masks can become uncomfortable to wear for long periods. Powered RPE can help improve the comfort of wearing RPE and there are many innovations and designs that make such equipment lighter and more comfortable, so employees are more likely to wear them and use them properly. Again, if such equipment is used and relied on to protect employees, not only does it need to be worn correctly but if it is of the non-disposable type it also needs to be maintained, cleaned and stored properly. It is always best to check this with the manufacturer or supplier.

With any of the controls mentioned above – elimination, substitution, reduction or prevention – supervisors and employees need to be trained on how to use them properly and advised on why the controls are necessary.

Some countries with mature occupational health records have more data on workers that have been exposed to various hazards and how many have developed an illness resulting from that exposure. In some developing regions, however, the occupational health records are not as robust and are still catching up with economic development.

It is difficult to find up-to-date figures on the scale of the silica dust lung cancer problem in the Middle East; however, a study published in 2012 called ‘Estimated Burden of Disease Attributable to Selected Occupational Exposures in The United Arab Emirates’ found lung cancer to be one of the biggest workplace killers.

Other countries have produced their own estimates of the scale - workplace exposure to silica dust is estimated to be responsible for around 800 lung cancer deaths a year in Britain.

So what can we do to reduce the number of people contracting lung cancer from exposure to silica dust at work? New technology and exposure limits might not be necessary, because using the current technology available and better compliance with current controls could make a big difference. Dr Lesley Rushton, of Imperial College London, has predicted that in Britain if compliance with current control measures was increased from its estimated 30% to 90% compliance then around 600 cases a year of occupational lung cancer deaths could be prevented.

So, a small change in behaviours and compliance could make a big difference to long-term illness and suffering. This is why it is important for an employer to talk to their employees to help identify the suitable controls and equipment and also to help identify any problems or where controls could be improved. The employees will then see that you take their health and safety seriously and are likely to feel positive and engaged with the company, work and task. Such employees are likely to be more productive. When you have employees that are productive, happy and healthy you have the building blocks for a sustainable workforce.

The straw walk

There can be a macho attitude towards hazards in the workplace, especially if the harmful affects do not occur immediately.

If you need to get the message across to a workforce or supervisors to improve compliance with silica dust control measures, the following is a trick you can use.

If you have a group of people, first make sure no one is asthmatic or has a heart or other medical condition (if so excuse them from this exercise). Then give everyone a straw and ask them to walk at least 50 metres and back and then walk up two flights of stairs or run on the spot for 30 seconds.

Then get them to pinch the end of their nose and breathe through the straw for a few seconds. You can then explain to them that this is what it could be like to breathe with a lung disease caused by exposure to silica dust. If they do not want to have to breathe like this in the future, then that is why they need to use the control measures available, either suppression/extraction or respiratory protection. I have found that this trick can really get the message across.

Published: 22nd Jul 2015 in Health and Safety Middle East

Share this article with your friends
BROUGHT TO YOU BY
Phil Bates
1 article on HSME