What is Silica?
Silica is a very common mineral found in sand and rocks such as granite, sandstone, flint and slate, and in some coal and metallic ores and it is also used as a filler in some plastics. In the workplace, the dust created when a material is cut, sanded, carved, broken, drilled or crushed can be hazardous to health.
Occupations with common exposure to silica include:
- Foundry workers
- Tunnelling workers
- Glass manufacturers
- Stone cutters
- Demolition and construction workers
- Brick cutters.
In workplaces, there are also other every day activities that can cause silica to be released into the air:
- Dust that is not cleaned up safely, for example by dry sweeping rather than wet cleaning
- Clothing and surfaces that are contaminated with dust
- Accumulated dust being ‘raised’ from the ground or other surfaces by moving vehicles and people.
What is Silicosis?
Silicosis is a completely preventable but incurable respiratory disease. It is caused by inhaling silica dust (or ‘crystalline’ silica). If this dust is inhaled, small particles of it can become embedded into parts of the lung and cannot be cleared by mucous or coughing. The dust is toxic to the lining of the lungs and causes a strong inflammatory reaction. Eventually, this can result in the lung tissue becoming irreversibly thickened and scarred – a condition known as fibrosis. This scar tissue prevents the lungs from taking in oxygen properly.
Serious exposure to high levels of silica can cause disease within a year, but it usually takes at least 10 to 15 years of exposure before symptoms occur. The disease tends to progress slower the longer the interval between exposure and the onset of symptoms.
As well as silicosis, silica exposure can also lead to Chronic Obstructive Pulmonary Disorder (COPD), tuberculosis and lung cancer.
Is all dust dangerous?
Low level or infrequent exposure to dust is unlikely to be dangerous but regular exposure to high levels of dust in the workplace can affect the respiratory system and cause workers to become seriously ill. Dust is listed as a hazardous substance in the Control of Substances Hazardous to Health Regulations 2002 (COSHH) and dust exposure occurs across different industries and working environments.
Types of hazardous dust may include:
- Asbestos dust
- Construction dust
- Paper dust
- Wood dust
- Flour dust
- Coal dust
- Cotton dust
- Metal dust.
Inhalation of the dust types listed above can lead to serious lung diseases, such as cancer, byssinosis (caused by exposure to cotton dust), chronic bronchitis, silicosis, asbestosis, asthma, Chronic Obstructive Pulmonary Disorder (COPD), and ‘metal lung disease’ (caused by exposure to cobalt-containing hard metals).