Silica Basics

Silica is present in many common materials, including:

• Concrete, cement, and mortar
• Stone, brick, tile, and masonry products
• Drywall and plaster
• Asphalt, sand, and soil
• Engineered stone

Exposure occurs when silica-containing materials are cut, ground, drilled, sanded, crushed, or demolished. These tasks can release fine dust particles that are small enough to stay airborne and be breathed in.

The smallest respirable particles are invisible and can reach deep into the lungs.

When respirable crystalline silica is inhaled, the particles lodge deep in the lungs where the body cannot remove them. Over time, the lungs form scar tissue, which reduces their ability to move oxygen into the bloodstream.

Damage can continue even after exposure stops and is linked to serious illnesses such as lung cancer, chronic obstructive pulmonary disease (COPD) and silicosis, an irreversible lung disease caused by inhaling silica dust. Symptoms of silicosis include a long-lasting cough, problems breathing, inflammation in your airways and scarring in your lung tissue. These illnesses may develop after repeated or high short-term exposures, and there may be no symptoms at first—making prevention especially important.

Prevention works. Silica-related illness is preventable when exposure is controlled. Reducing dust at the source, supporting safe work practices, and using protective equipment when required can significantly lower risk.

Preventing exposure depends on understanding where silica may be present and applying controls consistently across worksites.

Crystalline Silica
A natural mineral (silicon dioxide, SiO₂) found in sand, stone, rock, and mineral ores, most commonly as quartz. It becomes a health hazard when fine dust is created and breathed in.

Respirable Crystalline Silica
The smallest particles of crystalline silica dust that are invisible to the eye and can be breathed deep into the lungs. These particles are the main cause of silica-related disease.

Silica Dust
Fine dust released when materials containing crystalline silica are cut, ground, drilled, crushed, sanded, or otherwise disturbed.

Silicosis
An irreversible lung disease caused by inhaling silica dust. Symptoms of silicosis include a long-lasting cough, problems breathing, inflammation in your airways and scarring in your lung tissue.

Chronic Obstructive Pulmonary Disease (COPD)
A long-term lung disease that makes breathing difficult. Exposure to respirable crystalline silica can contribute to the development or worsening of COPD.

Hierarchy of Controls
A method for preventing exposure to hazards by prioritizing the most effective controls first. For silica, this includes eliminating or substituting materials or processes where possible, using engineering and administrative controls to reduce dust, and relying on PPE only as the last layer of protection.

Engineering Controls
Physical changes to tools, equipment, or work processes that reduce silica dust at the source, such as wet methods, local exhaust ventilation, dust collection systems, or process enclosure.

Exposure Assessment
The process of identifying silica-generating tasks and evaluating whether workers may be exposed to harmful levels of silica dust. This typically starts with reviewing materials and tasks and confirming that controls are working effectively.

Take-Home Exposure
Silica dust that leaves the worksite on clothing, skin, tools, or equipment and can expose others, including family members. Good housekeeping and hygiene practices help prevent this.