With the Government having banned asbestos almost two decades ago, construction companies are still working to remove the fibres from buildings. Although companies are training staff to work safely within asbestos exposure sites, they do not always realise the dangers of silica dust. However, there is a mineral found in many materials, commonly used on construction sites, which can be equally as dangerous with high exposure.

What is Silica Dust?

Crystalline Silica (Silica dust) is a naturally occurring substance including being the main constitute of sand. It is also the second most abundant mineral in the world. Silica is generally harmless in solid form, and illnesses caused by exposure to it are rare considering the daily contact. Naturally occurring Silica is often found in solid substances which are processed to extract the compound.

Why is it dangerous?

Crystalline Silica is dangerous when it becomes airborne with inhalation of the dust causing many diseases in the lungs including silicosis, bronchitis, lung cancer and systemic autoimmune diseases. Construction workers are at the highest risk of exposure as Silica is a major component to many commonly used construction materials such as;

  • Sand
  • Cement
  • Granite
  • Clay
  • Stone

The dust is created through activities like cutting, drilling and grinding.

Respirable Crystalline Silica (RCS) particles are very small and impossible to see with the naked eye. Every harmful or hazardous substance covered by the Control of Substances Hazardous to Health (COSHH) Regulations is given a Workplace Exposure Limit (WEL). The maximum WEL of RCS is 0.1mg/m3 expressed as an 8-hour time-weighted average.

This limit is a guide for how much of the substance an employee should be exposed to within a certain timeframe, so employers can take the appropriate steps to ensure their employees are safe. This can be done by undertaking a risk assessment specifically for Silica dust exposure to find the average daily exposure and how to reduce it.

The Health and Safety Executive recommends not using compressed air to remove dust from clothing or dry sweeping to clear dust – use a vacuum or water sprays to prevent the dust from becoming airborne.

Silica-Related Diseases


Silicosis is caused by inhaling substantial amounts (exposure to a larger amount of RCS than the WEL dictates) of Respirable Crystalline Silica over time. The dust particles are attacked by the immune system once they enter the lungs. This causes inflammation of the airways and eventually leads to hardened scarring of the lung tissue (fibrosis). Lung tissue will not function properly when scarred in this way.

Symptoms usually take years to develop and many do not notice any issues until they’ve stopped working with Crystalline Silica.

There are three types of Silicosis;

Chronic silicosis

Chronic silicosis is the most common form of Silicosis. This results from long-term exposure to low amounts of crystalline silica, usually more than twenty years. People with this disease may have trouble breathing.

Accelerated silicosis

This is caused by exposure to substantial amounts of Silica dust over a period of approx. 5 to 15 years. With this condition, symptoms develop faster than chronic silicosis.

Acute silicosis

This can result from short-term exposure to extreme amounts of Silica dust. The lungs may fill with fluid to cause severe shortness of breath and low blood oxygen level.

All forms of Silicosis are irreversible. The conditions are preventable by using the appropriate Personal Protective Equipment (PPE) for the work that you are undertaking.

Silica exposure can also cause Chronic Obstructive Pulmonary Disease (COPD) which occurs when the lungs become inflamed, damaged and narrowed. Like Silicosis, the condition cannot be cured or reversed. However, it is largely preventable by not smoking and using appropriate PPE when exposed to Silica dust.

Employers must warn employees about the risks to their health, supply the necessary PPE and educate workers on the correct procedures to reduce the risk of exposure. Personal Protective Equipment should not be used as an alternative to control procedures. Depending on the work being undertaken, workers may be required to wear equipment such as hearing protection, hard hats, eye/face protection (if not combined) and work overalls. Respiratory Protective Equipment should be compatible with the PPE being used.

Using the correct Respiratory Protective Equipment (RPE) for the type of work you are doing is important to limiting the amount of exposure to RCS. RPE is given an Assigned Protection Factor (APF) of between 4 and 2000, meaning the wearer will only breath in that percentage of the amount of dust in the air.

The necessary level of APF for construction dusts, including Silica is generally APF 20. Disposable or half masks can become uncomfortable to wear over long periods of time. Powered RPE can help minimise this discomfort. For people working for longer than an hour without a break, powered RPE should be considered. Some work may require a tight-fitting respirator, in this case Face Fit testing is needed to ensure the equipment fits correctly.

The work you are completing may require you to wear a tight-fitting respirator. To use a tight-fitting respirator, you will need to make sure it fits correctly prior to use. Each respirator should be fitted individually for each member of staff. Here at SAMS Ltd, we offer a Face Fit course that complies with the Health & Safety Executive’s (HSE) guidance notes.