02 May Silica Exposure – Preventing Silicosis

Silica Exposure – Preventing Silicosis

Silicosis is a serious, permanent lung disease caused by breathing respirable crystalline silica dust. Crystalline silica is found in many common construction materials, including concrete, brick, block, mortar, stone, rock, sand, and soil.

When these materials are cut, drilled, ground, crushed, chipped, or otherwise disturbed, very small silica particles can become airborne. These particles may be too small to see, but they can travel deep into the lungs and cause permanent damage.

When Can Silica Exposure Occur?

Workers may be exposed to respirable crystalline silica during activities such as:

• Cutting, sawing, grinding, or drilling concrete, brick, block, mortar, or stone.
• Jackhammering or chipping concrete and masonry.
• Drilling rock or silica-containing soil.
• Crushing or demolishing concrete or masonry.
• Tuckpointing or mortar removal.
• Abrasive blasting using silica-containing materials or blasting silica-containing surfaces.
• Mixing or handling dry materials containing crystalline silica.
• Cleaning areas where silica-containing dust has accumulated.
• Dry sweeping or using compressed air on silica-containing dust.

Dust-generating activities performed in enclosed or poorly ventilated areas can create particularly hazardous exposures.

Health Effects of Silica Exposure

Breathing respirable crystalline silica can cause silicosis, which results from inflammation and scarring of the lungs. The damage is permanent and can continue to progress even after exposure has stopped.

Silica exposure is also associated with other serious health effects, including:

• Lung cancer.
• Chronic obstructive pulmonary disease (COPD).
• Kidney disease.
• Increased susceptibility to tuberculosis and other respiratory infections.

Silicosis may develop gradually after years of exposure, but very high exposures can cause the disease to develop much more quickly.

Symptoms may include:

• Persistent cough.
• Shortness of breath.
• Fatigue or weakness.
• Chest pain.
• Difficulty breathing during physical activity.

Employees experiencing respiratory symptoms should report them and seek appropriate medical evaluation.

Control Silica Dust at the Source

The most effective way to prevent silicosis is to prevent silica-containing dust from becoming airborne or reaching the employee’s breathing zone.

Depending on the task, controls may include:

• Using wet-cutting, wet-drilling, or other water-delivery systems to suppress dust.
• Using tools equipped with local exhaust ventilation and appropriate dust collection systems.
• Using HEPA-filtered dust collection equipment when required.
• Isolating or enclosing dust-producing operations.
• Restricting access to areas where significant silica exposure may occur.
• Using alternative materials or work methods that generate less silica dust.
• Following established silica exposure-control procedures and manufacturer instructions.

Never disable, remove, or bypass a tool’s dust-control system.

Safe Cleanup Practices

Improper cleanup can put settled silica dust back into the air.

• Use HEPA-filtered vacuums or wet-cleaning methods whenever feasible.
• Do not dry sweep or dry brush silica-containing dust when these activities could contribute to employee exposure unless other cleaning methods are not feasible.
• Do not use compressed air to clean clothing or surfaces when it could contribute to silica exposure unless the compressed air is used with a ventilation system that effectively captures the dust cloud.
• Dispose of collected dust and debris in a manner that minimizes airborne dust.

Respiratory Protection

Engineering and work-practice controls should be the primary means of reducing silica exposure. Respirators may also be required for certain tasks or when other controls cannot adequately reduce exposure.

When respiratory protection is required:

• Use the type of respirator specified for the task and exposure.
• Employees must be included in the company’s Respiratory Protection Program.
• Required medical evaluations and fit testing must be completed.
• Employees must be trained in proper respirator use, inspection, maintenance, and limitations.
• Facial hair or other conditions must not interfere with the respirator’s seal.

A disposable dust mask should not automatically be assumed to provide adequate protection against respirable crystalline silica.

Protect Yourself and Others

Employees working around silica-containing materials should:

• Follow the company’s silica exposure-control procedures.
• Use required water-delivery or dust-collection systems.
• Keep other employees away from dust-producing operations when necessary.
• Wear required PPE and respiratory protection.
• Never intentionally create unnecessary dust.
• Wash hands and face before eating, drinking, smoking, or leaving the work area.
• Avoid bringing silica-containing dust home on clothing, footwear, tools, or personal items.
• Report damaged or ineffective dust-control equipment immediately.
• Report unusual dust conditions or respiratory symptoms to a supervisor.

Remember

Silica dust may be invisible, but the damage it causes can be permanent. Control the dust at its source, use proper work practices and respiratory protection when required, and never create unnecessary airborne dust.

The best way to prevent silicosis is to prevent workers from breathing respirable crystalline silica in the first place.