Silica dust exposure is a serious occupational hazard that affects workers across numerous industries, particularly in construction, mining, demolition, foundries, and manufacturing.
When materials containing crystalline silica are cut, ground, or drilled, fine particles become airborne—posing a lifelong health threat to exposed workers.
Without proper controls and compliance programs, silica dust can lead to chronic illness, permanent disability, or death. Employers have both a legal and moral obligation to control exposure and protect their workers.
What Is Silica Dust and Where Is It Found?
Silica is a naturally occurring mineral found in sand, rock, quartz, concrete, brick, and mortar. When these materials are cut, crushed, or sanded, they release respirable crystalline silica—invisible, airborne particles small enough to penetrate deep into the lungs.
Common activities that generate silica dust include:
- Cutting or grinding concrete and stone
- Sandblasting
- Jackhammering
- Demolition of structures
- Mixing dry cement
- Tunneling, mining, and excavation
Even short-term exposure without protection can lead to long-term health issues.
Health Risks Associated with Silica Dust Exposure
Silica dust is a Group 1 carcinogen classified by the International Agency for Research on Cancer (IARC). Inhalation of fine crystalline silica particles can lead to:
- Silicosis – A progressive, irreversible lung disease
- Lung cancer
- Chronic obstructive pulmonary disease (COPD)
- Kidney disease
- Autoimmune disorders
- Increased risk of tuberculosis in workers with compromised lungs
Symptoms of silicosis may not appear for years, making early prevention critical. Learn more from CCOHS Silica Information. (DoFollow)
Occupational Exposure Limits (OELs) in Canada
Most Canadian provinces and territories set occupational exposure limits for crystalline silica at or below:
- 0.025 mg/m³ (respirable fraction) as a time-weighted average (TWA) over an 8-hour shift
Exceeding this limit requires immediate intervention. Jurisdictions including Ontario, BC, and Alberta enforce strict penalties for non-compliance under OHSA legislation.
How to Control Silica Dust Exposure
Control strategies follow the Hierarchy of Controls: eliminate, substitute, engineer, administer, and protect.
1. Elimination or Substitution
- Use pre-cut materials to eliminate on-site cutting
- Replace silica-containing materials with non-silica alternatives when possible
- Avoid dry sweeping—use wet methods instead
2. Engineering Controls
These are the most effective methods short of elimination:
- Water suppression systems on saws, drills, and grinders
- HEPA-filtered vacuum dust collection systems
- Isolation of high-exposure tasks in enclosed or ventilated spaces
- Use of enclosed cabs for equipment operators
Example: Using a saw with integrated water delivery can reduce airborne dust by up to 90%.
3. Administrative Controls
These include procedural changes such as:
- Limiting duration and frequency of dusty tasks
- Scheduling dusty operations during low-traffic hours
- Rotating staff to reduce individual exposure
- Posting warning signs and restricting access to dusty zones
- Maintaining proper housekeeping using wet methods or vacuums
4. Personal Protective Equipment (PPE)
When exposure cannot be eliminated, provide appropriate PPE:
- NIOSH-approved respirators (N95 or better)
- Reusable elastomeric respirators with P100 filters for high-exposure work
- Full-face protection for long or intense jobs
- Coveralls to prevent dust from being carried home
All workers should be fit-tested and trained in proper use, care, and limitations of PPE.
5. Air Monitoring and Exposure Assessment
Regular air sampling ensures silica levels remain below the OEL. Employers must:
- Conduct baseline and periodic monitoring
- Use personal sampling pumps for accurate results
- Document exposure data
- Provide results to employees
Hire a qualified occupational hygienist for professional monitoring and assessments.
Training and Worker Awareness
Every worker potentially exposed to silica dust must receive training on:
- Health risks
- Exposure sources
- Safe work procedures
- PPE use and limitations
- Emergency procedures
Use safety bulletins, toolbox talks, and posters to reinforce key messages. For more safety training resources, visit OHSE.ca. (Internal link)
Medical Surveillance and Recordkeeping
Employers may be required to offer medical surveillance for workers in high-risk roles, especially where exposure exceeds limits. This includes:
- Regular health exams and lung function tests
- Detailed exposure history
- Long-term records retention
Medical data must be kept confidential and used only for health protection.
Silica Dust in Construction: A Case Study
Construction workers, especially those in concrete cutting and drywall sanding, are among the most affected. A recent study by WorkSafeBC found that many sites failed to implement even basic dust control.
After an inspection blitz, enforcement orders rose by over 200%. In response, companies improved:
- Use of wet cutting techniques
- Deployment of vacuum systems
- Distribution of proper respirators
Compliance and Legal Accountability
Failure to control silica dust can result in:
- OHSA citations and fines
- Worker compensation claims
- Criminal charges under Bill C-45 for negligence
- Reputational damage and work stoppages
Employers must demonstrate due diligence and comply with provincial standards and federal guidelines from Employment and Social Development Canada. (DoFollow)
Conclusion: Protect Now, Prevent Forever
Silica dust exposure is a silent but deadly workplace hazard. Through risk assessments, controls, training, and compliance, employers can prevent devastating health outcomes and meet regulatory requirements.
Whether in construction, mining, or manufacturing, the time to act is before exposure occurs. Protect your workers today to preserve their health tomorrow.
