Research from Imperial College London suggests that around 900 new cases of lung cancer each year in Britain can be attributed to past exposure to Silica dust in construction.
It is estimated that nearly 800 people die a year from lung cancer caused by Silica dust exposure at work with about half a million people exposed to Silica dust at work in the UK.
The Health and Safety Executive have published a draft plan on what they will be doing to help control and educate people on the risks of exposure to Silica dust.
Silica dust is a natural occurring substance found in stone, rocks, sand and clay as well as products like bricks, tiles, concrete and certain plastic composites. All these materials have different ranges of Silica contained within them, and it is important to understand what materials you are working with so you can manage the risk appropriately.
Approximate ranges of crystalline silica found in materials
Sandstone 70-90%
Plastic Composites 19-90%
Concrete/Mortar 25-70%
Granite 20-45%
Tile 20-40%
Slate 20-40%
Brick up to 30%
Silica dust is only harmful when it is inhaled deep into your lungs, where oxygen is taken up into the blood. It is the respirable fraction of the dust that is hazardous. Respiratory particles are typically less than around 5 microns in size. Compare this to the full stop at the end of this sentence, which is around 200-300 microns in diameter, and the finest sand on a beach, which is about 50-70 microns.
Exposure can be divided into two types acute and chronic. Acute silicosis occurs after several months or up to 2 years severe exposure to extremely high concentrations of respirable crystalline dust. Symptoms of acute exposure include severe shortness of breath, weakness and weight loss. There are three main types.
- Chronic exposure can lead to lung cancer, considered to be the most serious of consequences.
- Silicosis which is the result of scarring and then thickening of the lung tissue caused by inhalation of Silica dust.
- Emphysema which is a result of gradual damage to the air sacs in the lungs, making the sufferer progressively short of breath.
Numerous control mechanisms can be used.
Local exhaust ventilation can be employed to suck dust away before it can be breathed in.
One tool extraction can be integrated or mounted onto hand –held tools to capture the dust while it is being used.
Suppression is another method, using water to constantly dampen and reduce dust levels is a simple relatively low cost control. It is important to remember that wetting just be work starts is not enough and will not work!
Personal protective equipment in the form of FFP3 standard, or powered masks/hoods if the work is of a long duration is advisable.
Making sure that all site operatives are trained to fully understand the risks and dangers of exposure to Silica dust and they understand how to use all the control mechanisms in use. Safety briefings are the ideal platform to educate people.