Our lungs are essential to our overall well-being. They provide the air we need for our organs and our cells to function, and they expel waste, predominantly carbon dioxide. But there is a lot that your lungs cannot expel and when certain material finds its way into your lungs, the damage can be serious and, in some cases, irreversible.
For workers in many construction, mineral and fabricating industries, there are significant hazards from dust and airborne particulates and there have been increasing cases of workers, including quite young workers, being diagnosed with an aggressive and incurable lung disease called silicosis.
According to the Medical Journal of Australia in November 2018 “approximately 35% of the workers screened in Queensland were found to have accelerated silicosis, and there is a high rate of progressive massive fibrosis — a stage in which the inflammation and scarring in the lung is very active and the worker is highly likely to become permanently disabled or die. These cases are affecting young men (the youngest to date is aged 21 years), often with dependent families, early in their working careers.”
Silica is silicon dioxide, a naturally occurring mineral that forms the major component of most rocks and soils. There are non-crystalline and crystalline forms of silicon dioxide. The non-crystalline forms of silica do not cause this kind of lung damage but it is still advisable to take steps to avoid exposure.
Crystalline silica (silica) is found in sand, stone, concrete and mortar. It is also used to make a variety of products including composite stone used in kitchen and bathroom benchtops, bricks, tiles and even some plastics. When workers cut, crush, grind, drill, or polish materials that contain silica, dust particles are generated. These ‘respirable particles’ can be so small that they are not even visible to the eye and small enough to lodge deep in the lungs and cause illness or disease including silicosis.
Activities that can generate respirable silica dust particles include:
- the fabrication and installation of composite (engineered or manufactured) stone countertops
- excavation, earth moving and drilling plant operations
- clay and stone processing machine operations
- paving and surfacing
- mining, quarrying and mineral ore treating processes
- general construction work
- brick, concrete or stone cutting; especially using dry methods
- abrasive blasting (blasting agent must not contain greater than 1 per cent of crystalline silica)
- foundry casting
- sawing, grinding, jackhammering or chiselling of concrete or masonry
- hydraulic fracturing of gas and oil wells, and
- pottery making.
If a worker is exposed to and breathes in silica dust they could develop a variety of lung complaints including chronic bronchitis, emphysema, and any of the forms of silicosis, as well as lung cancer, kidney damage or scleroderma (a disease of the connective tissue of the body resulting in the formation of scar tissue in the skin, joints and other organs of the body).
There are three categories of silicosis and these can depend on level of exposure and over what period. Acute silicosis can develop after only a short exposure to very high levels of silica dust, within a few weeks or years. Chronic silicosis can also develop after long term exposure to lower levels of silica dust.
Even reduced lung function can have a serious and significant impact on your lifestyle, your ability to work, and your overall health so it’s important to manage the risk of exposure by choosing the most suitable control measures and usually more than one control is necessary to effectively manage the hazard and protect workers.
Personal protective equipment including appropriate respiratory equipment (generally a minimum of a P2 efficiency half face respirator) and work clothing that does not collect dust are essential base-line controls.
Isolation controls focus on how and where the work space for high risk activities are set up. Consider enclosures and the worker’s position in the work area, or even consider automation if it is a viable option.
Engineering controls reduce the risk of exposure to silica dust with measures such as local exhaust ventilation, water suppression (wet cutting) or using tools with dust collection attachments. Vacuuming is recommended over sweeping while cleaning up.
Employers should also be sure to have appropriate administrative controls in place, including appropriate policies and ongoing strategies for identifying, mitigating and monitoring (such as regular air quality monitoring) the hazard on an ongoing basis.