What Is Crystalline Silica?
Crystalline silica is a common mineral found in:
- Concrete
- Brick
- Block
- Mortar
- Stone
- Rock
- Sand
- Some ceramic tiles
When these materials are cut, ground, drilled, or crushed, tiny dust particles are released that can be breathed deep into your lungs.
Health Risks of Silica Dust
Silicosis
- Permanent, irreversible lung disease
- Causes scarring and stiffening of lung tissue
- Makes breathing difficult
- Gets worse over time, even after exposure stops
- No cure, only treatment for symptoms
Other Health Problems
- Lung cancer
- Chronic obstructive pulmonary disease (COPD)
- Kidney disease
- Increased risk of tuberculosis
- Autoimmune disorders
High-Risk Construction Activities
These tasks create dangerous levels of silica dust:
- Cutting/sawing concrete or masonry
- Grinding concrete surfaces
- Drilling concrete or stone
- Chipping or breaking concrete
- Dry sweeping or blowing dust with compressed air
- Using jackhammers on concrete
- Crushing rock or concrete
- Abrasive blasting with sand
- Demolition of concrete or brick structures
- Mixing concrete or mortar
OSHA's Silica Standard
OSHA has specific rules to protect workers:
- Permissible Exposure Limit (PEL): 50 micrograms per cubic meter, averaged over an 8-hour day
- Action Level: 25 micrograms per cubic meter, requiring additional monitoring and medical surveillance
- Required use of engineering controls, work practices, and respirators when needed
- Training on silica hazards and protection methods
- Medical exams for highly exposed workers
Controlling Silica Dust
Engineering Controls
These methods keep dust from getting into the air:
Water Methods
- Use saws with integrated water delivery systems
- Keep water flowing at the right rate
- Make sure water is directed at the cutting point
- Clean up slurry before it dries and becomes airborne
Vacuum Methods
- Use tools with built-in HEPA-filtered vacuum systems
- Ensure vacuum is on and working properly
- Use the right sized shroud or dust collection attachment
- Empty vacuum bags following safe procedures
Work Practice Controls
These methods reduce exposure even further:
- Work upwind when possible
- Limit the number of workers in dusty areas
- Use water spray to keep stored materials from creating dust
- Never use compressed air to clean surfaces or clothing
- Use wet methods for cleaning up dust
- Dispose of collected dust in sealed containers
Personal Protective Equipment
When engineering controls aren't enough:
Respirators
- N95 filtering facepiece respirators for lower exposures
- Half-face respirators with P100 filters for higher exposures
- Full-face respirators or powered air-purifying respirators for even higher exposures
- Must be properly fit-tested and worn correctly
- Require medical evaluation before use
Other PPE
- Eye protection to prevent dust irritation
- Coveralls to keep dust off clothing
- Washable or disposable work clothes
- Facilities to wash hands and face before eating/drinking
Signs of Silica-Related Health Problems
See a doctor if you experience:
- Shortness of breath
- Severe cough
- Weakness and fatigue
- Weight loss
- Chest pain
- Fever
Early stages of silicosis often have no symptoms, so medical testing is important even if you feel fine.
Protecting Yourself
- Know which materials contain silica
- Learn which tasks create silica dust
- Use the dust controls provided by your employer
- Wear your respirator when required
- Don't eat, drink, or use tobacco products in dusty areas
- Wash hands and face before eating, drinking, or smoking
- Change into clean clothes before leaving worksite if possible
- Participate in air monitoring programs
- Get medical exams if offered
Employer Responsibilities
Your employer should:
- Develop a written exposure control plan
- Designate a competent person to implement the plan
- Restrict housekeeping practices that expose workers to silica
- Offer medical exams to highly exposed workers
- Train workers on silica risks and controls
- Keep records of exposure measurements and medical exams