Silica or silicon dioxide is a naturally occurring mineral found abundantly in different types of stones and soils. Silicon dioxide is found both in crystalline and non-crystalline forms. The crystalline form is known as free silica (or just ‘silica) and poses significant health hazards as compared to the non-crystalline form.
Dust particles of silica are tiny enough to enter deep into the lungs and cause respiratory problems along with lung damage. When exposed over a long time, the conditions can exacerbate leading to major and permanent lung damage.
Most Common Sources of Silica
Silica is most commonly found in quartz, which is an integral component of several types of soils and rocks. For example, granite has 40% quartz and sandstones have about 47% while shale has about 22% quartz. Quartz is also found extensively in sand located on beaches, stream beds and desserts along with man-made composites like concrete or mortar.
Who Are Affected by Exposure to Silica Dust?
Workers in various industries are regularly exposed to silica dust and are at high risk. This includes those in drilling, cutting, excavating or earth moving operations, workers working with stone or clay, those in the mining or construction sector, workers involved in concrete, stone or brick cutting, those in foundry casting or those involved with regular abrasive blasting.
What are the Health Hazards?
Being a tiny particle, silica dust is inhaled by the workers while they are at work. When inhaled over the years, the prime health hazard is silicosis and chronic obstructive pulmonary disease (COPD), which is a respiratory disease.
Epidemiological data also suggests that regular exposure to silica dust can affect the kidneys and lead to renal diseases. However, the prime cause of concern is definitely silicosis.
What is Silicosis?
Silicosis is a terminal disease of the lungs that is caused due to long-term exposure or short-term, high-intensity exposure to silica dust. When there is enough accumulation of silica dust in the lung parenchyma, it leads to fibrosis – the build of connective tissues that thickens the lungs and affects its normal functioning.
Silicosis is a type of pneumoconiosis, a lung disease caused due to inhalation of toxic dust particles. It is an irreversible condition with gradual progression.
Depending on the exposure, silicosis has three levels. The first is acute silicosis that results from a very high exposure to silica over a few weeks or months (high-intensity, short-term exposure).
The second is accelerated silicosis that develops due to high exposure over at least five to ten years.
The third is chronic silicosis that forms due to regular exposure for more than ten years and above. This condition develops slowly and initially, the worker may not show any symptoms at all.
Typical symptoms of silicosis include breathlessness, pain while breathing, inflammation of the lungs, coughing and fever. In its most severe form, silicosis can lead to death due to extreme difficulty in breathing.
Ensuring Worker Safety While Working with Silica
According to doctors, silicosis is about to become Australia’s most widespread work-related pulmonary disease crisis since the asbestos crisis. In September 2018 alone, 35 cases of workers with silicosis were reported just in Queensland. Out of these, six were at the fatal stage.
Waking up to the impending disaster, the Government is mulling several steps and regulations to make the workplace safer for workers across all sectors who are exposed to silica dust.
Nationwide data is being collected to understand the extent of damaged caused. Furthermore, the Health Minister has urged all states to begin an awareness campaign both among workers and contractors regarding silicosis. The states have also agreed, in principle, to maintain a register to keep a track on the health of workers who are exposed to silica dust.
He has also announced the Government’s plans to request Safe Work Australia to immediately review the situation and formulate laws and regulatory standards to stem the epidemic.
The Existing Regulations
While more needs to be done to control the spread of silicosis and protect workers from exposure, certain regulations are already in place.
The Australian Institute of Occupational Hygienists Inc. (AIOH) – the largest society for occupational hygiene in Australia, permits an exposure of 0.1mg/m3 as a standard for measuring the level of exposure.
Safe Work Australia advises workers to visit their doctors for regular tests if they are exposed to silica dust extensively and regularly. Even workers who had been exposed more than a decade ago are advised to go for appropriate tests and check-up.
The tests include different general health check-ups, medical history of the worker, current symptoms being exhibited along with a chest X-ray. The entire procedure has two sets of questionnaires that offer an insight into the conditions that caused silicosis and the present level of progression.
The first questionnaire is sent to the PCBU or the organization/contractor that has employed the worker. This questionnaire aims to gather information about workplace conditions so that further regulations can be introduced to make the workplace safer.
The second questionnaire deals with the worker’s health condition. It is retained by the patient and is used to evaluate his condition during subsequent check-ups.
Moreover, dry-cutting of stones has already been made illegal in Queensland due to the widespread reporting of silicosis in the state. Although other states are yet to take similar steps, the Government is nudging them to take positive measures in the same line.
Contractors are being urged to provide workers with cutting tools with dust collection and water suppression gadgets attached to them. Such gadgets significantly reduce the emission of silica dust while working with stones and other materials rich in silica.
Apart from the above, workers must be provided with a respiratory filter to reduce the impact of exposure to silica dust. These filters are graded according to their capacity to filter out harmful particles from the air. Filters graded as P1 have the lowest capacity while those graded P3 have the highest capacity.
Contractors should, therefore, provide workers with P3-graded respiratory filters, which are capable of reducing silica dust particles inhaled by workers by up to 98%.