Hazardous dusts: Are your workers at risk?
Dust, i.e. airborne particulate matter, is currently being given a lot of attention in the media. Asbestos was used extensively in flame-retardant clothing, gaskets, building materials, insulation and floor coverings for a long period of time in the 20th century. Medical investigations determined that the respirable exposure to the airborne fibres was extremely harmful and led to lung cancer. Various other hazardous dusts are still present in many workplaces.
Why is dust a significant issue?
Asbestos, silica, coal, synthetic mineral fibres and wood dusts are big concerns because exposure to these airborne materials can lead to long-latency diseases. Such diseases can result in suffering over a long period of time and premature death, often many years or even decades after the initial exposure. High-level dust exposure in the workplace can also cause serious respiratory diseases such as asbestosis, mesothelioma, silicosis, and other chronic obstructive pulmonary diseases and cancers of the respiratory system. Less serious – but still undesirable – health effects include asthma, itchy eyes, sore throats and irritated noses.
The common element with all dusts is the route of exposure. Inhalation through the mouth or nose creates a risk to workers. Dusts are often categorised as inhalable or respirable. Inhalable dusts in general terms are larger in particle size (> 5 micron) and often get caught in the mucous coating of the respiratory tract. Respirable dusts however are much smaller in particle size, move with greater velocity and often end up in the gaseous exchange areas of the lungs. They are far more dangerous, and, if carcinogenic, can cause serious long-term harm when the cells in the lungs develop tumours.
Which businesses are most at risk from hazardous dusts?
The businesses most at risk are in the traditional blue-collar industries. Workers in mining, construction and manufacturing experience the highest levels of dust exposure. If you work in the following industries, you should review your current practices around health-related policies and procedures for the workforce:
- quarrying and mining;
- cabinet making;
- stonemasonry, including fabricated or manufactured stone products;
- tiling, brick laying and paving;
- carpentry and building;
- concreting, and concrete cutting or polishing; and
- agriculture and farming.
If you work in or manage any of these activities, seek expert advice on monitoring and implementing control measures specific to your risk of exposure.
Is your dust issue seriously harmful?
To find out how harmful your dust issue is, get some expert advice. Hygienists and environmental scientists may be able to provide information and knowledge to your business, your workers and their relevant representatives. Gather research and information from Safety Data Sheets (SDSs), industry groups, safety professional networks and unions.
From this information, look at the exposure levels in terms of Time Weighted Average (TWA) and Short Term Exposure Limit (STEL). These limits are not necessarily safe but are the maximum permissible exposures over a working shift, or in a 15-minute exposure period. The lower the number, the more hazardous the dust exposure.
The next step is to get a sample of the dust present in your work environment. You can delegate this task to a hygienist or health expert, as the testing is critical and the equipment needed is expensive to run and maintain. They will use sample pumps and analytical equipment to measure the types and concentrations of contaminants. Once the baseline is determined, you can consider actions and controls to find the most practicable solution.
Controlling workers’ exposure to dust
On construction sites, farms and other outdoor sites, dirt, debris and other particles are thrown about by the wind. Most of these are considered nuisance dusts and our mucous systems will prevent damage to the respiratory tract. Factories, workshops and other industrial sites will generate their own dust through grinding, sawing, drilling and other processing methods. Therefore, elimination is not always possible. What can you do instead? Here are a few suggestions to reduce both the level of dust and workers’ exposure to it:
- Install extraction, dilution or air purifying plant to remove or filter the dust particles. This can be in the general work area or specifically localised to where the dust is being generated. You can use High Efficiency Particulate Absorber (HEPA) filters to trap the airborne particles.
- Booths or sealed compartments where processing occurs are another engineering control. This would limit the effect on adjacent workers and restrict the effect of the exposure.
- When cutting, drilling or grinding stone, you may be able to use a liquid or water supply to reduce the amount of dust created.
- Reduce exposure times and stay upwind of dust. This is an administrative control that may be practicable in some instances. You could develop policies and procedures to warn workers of the dangers so they are better informed.
- Health monitor the effects. Spirometry is often used to measure lung function and may indicate a serious health condition long before symptoms are noticed.
- Discourage smoking in dusty workplaces. The combined reactive effects of smoking and dust exposure may exacerbate and accelerate workers’ exposure.
- Ensure the use of personal protective equipment. Wearing respiratory masks, or filtered air fed masks could also be effective in reducing exposure – although it is considered the lowest level in the hierarchy of controls, so should be used in conjunction with other controls.
Note that the risks, exposure routes and suggested controls for dust are also applicable to vapour, fume and smoke exposure.
Hazardous dusts are considered one of the highest risk factors in many workplaces. Many dusts that were once seen as innocuous, like asbestos, are now known to be carcinogens. Continuous scientific advancement in this field will likely lead to further concerns about the exposure to inhalation of other dusts and contaminants. Providing ongoing education and training to your workers, and reducing the concentrations of dust in your workplace, may alleviate or minimise the negative effects of these exposures.
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