At Pro Safety and Training we pride ourselves on keeping workplaces safe, and reducing liability for businesses. Recently we have been helping more and more of our customers with respiratory protection solutions including face fit training and courses, face fit testing and consulting. One issue we are coming across more and more is crystalline silica. This news post aims to provide information on crystalline silica.
What is Silica?
Silica is essentially a mineral that occurs naturally. Silica exists in many forms however Quartz is the crystalline form of silica and it is in this form that it poses the most risk to workers. Exposure to Quartz is a known contributor of respiratory diseases.
Crystalline silica can be naturally occurring (found during mining and quarrying), or can be found in a variety of products including:
- Concrete
- Compressed fibro cement sheeting
- Roof tiles
- Asphalt
- Bricks
- Pavers
- Sandstone
- Tiles
When crystalline silica is stable and undisturbed it poses very little risk. However when disturbed through demolition, use of power and hand tools and any other process that can create respirable dust it becomes a significant hazard.
How does Silica enter the body?
Crystalline silica enters the body primarily through inhalation. With crystalline silica particles being extremely small (1 to 6 microns in diameter) they reach deep levels inside our lungs. Our lungs have scavenger cells (called macrophages) which dissolve dust particles by surrounding them. If there are high exposure levels the scavenger cells cannot completely clear the dust, and scars develop in the air sacs. With increased scarring you get an increase in shortness of breath.
Above: Worker is exposed to crystalline silica exceeding exposure standards.
Which industry groups are at risk?
Several industry groups are at risk including:
- Building and construction
- Manufacturing
- Mining
- Quarrying
- Civil
- Road infrastructure
Tasks involving the following are at an increased level of risk:
- Blasting into clay, soils, granite or sandstone
- Use of a grinder on bricks, mortar, concrete, tiles or fibro cement
- Drilling into concrete and brickwork
- Brick and block cutting
- Use of jackhammers
- Cleaning up dust and debris
- Dismantling and removing plant and equipment (such as scaffold) that can be covered in dust
- Demolition of buildings
- Roadworks
Above: Crystalline silica is generated through the use of hand and power tools.
What diseases are caused by exposure to crystalline silica?
Several diseases can be caused by exposure to crystalline silica. These diseases have physical and psychological effects that don’t just affect the victim but also affect people around the victim such as carers, co-workers, family and friends.
Exposure can cause:
- Silicosis, this is essentially scarring of the lung tissue which causes shortness of breath
- Lung cancer- with smokers at increased risk
- Kidney damage
- Scleroderma, a disease in the connective tissue of the body resulting in the formation of scar tissue in joints, skin and other organs in the body
- Chronic bronchitis
- Emphysema
How do we protect against respirable crystalline silica?
Like any hazard, it is controlled through the hierarchy of controls:
Elimination- eliminating exposure to crystalline silica
Substitution- changing or switching products for a safer alternative
Isolation
Engineering- this includes ventilation and extraction systems and dust suppression systems
Administration- this includes training, supervision, policies and procedures, schedules and processes
PPE- this could include the use of coveralls, respirators and gloves.
What is the exposure standard for respirable crystalline silica?
The current level of exposure for crystalline silica is 0.1 mg/ m³. This is detailed in Workplace exposure standards for airborne contaminants.
How Fit Testing can help keep workers safe?
One control measure for crystalline silica is RPE (Respiratory Protective Equipment). RPE is a great way to keep us safe, however it only does this if the RPE selected is suitable for the application (correct type of filters and protection factor given), if the user wears it correctly and there is an adequate facial seal (face fit testing has proved it fits correctly) and the RPE is maintained correctly.
To ensure that the respirator seals correctly for the user of the RPE quantitative face fit testing can be conducted. This type of face fit testing involves use of specialised and calibrated equipment that samples air inside and outside the RPE and calculates a “fit factor”. If the “fit factor” exceeds a certain level the users passes the test essentially proving that the RPE seals on the face correctly.
By having correctly fitting and sealing RPE you can ensure that workers will have the highest level of protection possible against crystalline silica.
Useful links:
Silica and the lung- Workplace Health and Safety
Construction Dust- Respirable crystalline silica
