What Is Silica?
Silica is a natural substance found in most rocks, sand and clay and in products such as bricks and concrete. Silica is also used as filler in some plastics. In the workplace these materials create dust when they are cut, sanded, carved etc. Some of this dust may be fine enough to breathe deeply into your lungs and cause harm to your health. The fine dust is called respirable crystalline silica and is too fine to see with normal lighting.The quantity of silica contained in stone and other materials varies considerably between different types of stone:
Approximate crystalline silica content of different materials
Sandstone 70–90%
Concrete, mortar25–70%
Tile30–45%
Granite 20–45%, typically 30%
Slate 20–40%
Brick Up to 30%
Limestone 2%
Marble 2%
Occupational exposure to respirable crystalline silica can occur in many industries, including:
construction and demolition processes – concrete, stone, brick, mortar;
quarrying;
slate mining and slate processing;
potteries, ceramics, ceramic glaze manufacture, brick and tile manufacture;
foundries;
refractory production and cutting;
concrete product manufacture;
monumental and architectural masonry manufacture, stone fireplace and kitchen worktop manufacture;
grit and abrasive blasting, particularly on sandstone.
Certain activities create dust containing respirable crystalline silica, such as:
grinding, drilling, cutting, sanding, chiselling, blasting;
polishing, conveying;
fettling;
mixing and handling, shovelling dry material;
rock drilling/breaking/crushing/screening.
How can respirable crystalline silica harm your health?
By breathing in respirable crystalline silica, you could develop the following lung diseases:
Silicosis: Silicosis makes breathing more difficult and increases the risk of lung infections. Silicosis usually follows exposure to respirable crystalline silica over many years, but extremely high exposures can lead rapidly to ill health.
Chronic obstructive pulmonary disease (COPD): COPD is a group of lung diseases, including bronchitis and emphysema, resulting in severe breathlessness, prolonged coughing and chronic disability. It may be caused by breathing in any fine dusts, including respirable crystalline silica. It can be very disabling and is a leading cause of death. Cigarette smoking can make it worse.
Lung cancer: Heavy and prolonged exposure to respirable crystalline silica can cause lung cancer. When someone already has silicosis, there is an increased risk of lung cancer.
The health risks from respirable crystalline silica are insignificant when exposure to dust is adequately controlled.
RCS's fully trained engineers can carry out a full site survey to determine sources of respirable crystalline silica and provide options for potential Local Exhaust Ventilation (LEV) systems and stone dust control solutions. Our engineers are fully COSHH compliant.
Protecting Your Workers
Employers must comply with The Control of Substances Hazardous to Health Regulations 2002 (COSHH) (as amended) and need to:
assess the risks to your health – this is called a ‘risk assessment’;
keep a written record of the risk assessment if they employ more than five people;
tell you anything significant about the risk assessment;
consider where practicable substituting material with a lower respirable crystalline silica content;
prevent or control exposures to respirable crystalline silica by:following good occupational hygiene practice to achieve adequate control of exposure – more advice can be found in HSE’s COSHH essentials (see ‘Find out more’);
for respirable crystalline silica, control measures must be effective in keeping exposure below the Workplace Exposure Limit (WEL) (0.1 mg/m3 respirable dust, averaged over 8 hours);
where necessary, provide you with personal protective equipment;
maintain all equipment used as control measures in good working order;
instruct and train you to use equipment properly, and tell you about health risks;
monitor to ensure that controls are effective and that the WEL for respirable crystalline silica is not exceeded, (this may include measurement of the dust levels in your work area);
where appropriate arrange health surveillance.
What Can RCS Do For You?
RCS's engineers will endeavour to provide you with the most effective and cost-efficient solution for stone dust extraction, fully COSSH compliant, following current HSE guidelines and your own individual requirements. Call us on +44(0)1563 546807 or click here to contact us for more information.