Silica Dust: How to Reduce/Remediate the Health Risk it Presents on Construction Sites

Silica dust is a hazard in construction, mining and manufacturing industries. This article provides an overview of:

• what silica dust is
• the health risks it poses
• the regulations surrounding it
• how to control exposure
• how to remediate areas impacted by silica dust

What Is Silica Dust?

Silica is a natural mineral commonly found in materials widely used in the construction industry, including sand, stone, concrete and mortar. It exists in two forms:

• Crystalline silica: the more common and dangerous form and the focus of this blog.
• Amorphous silica: less structured and typically less hazardous.

Crystalline silica dust is generated when materials containing crystalline silica are cut, ground, drilled, crushed or otherwise disturbed. The particles released are microscopic, about 100 times smaller than a grain of sand; these particles can become suspended in the air where they can easily be inhaled.

Health Risks of Silica Dust Exposure

Prolonged or high levels of exposure to respirable crystalline silica can potentially lead to several health conditions which can include:

• Silicosis: an incurable and potentially fatal lung disease caused by inhaling silica dust. It occurs when tiny silica particles lodge in the lungs, causing inflammation and scarring.
• Lung Cancer: the International Agency for Research on Cancer (IARC) classifies crystalline silica as a Group 1 human carcinogen (meaning it is a substance known to cause cancer in humans). Long-term exposure significantly increases the risk of developing lung cancer.
• Chronic Obstructive Pulmonary Disease (COPD) – silica exposure can exacerbate or contribute to the development of COPD, including progressive lung diseases such as chronic bronchitis and emphysema.

Regulations and Standards

Given the serious health risks associated with exposure to respirable crystalline silica, regulations limiting occupational exposure to the material have been established. The Occupational Safety and Health Administration (OSHA) has set standards for workplaces including:

• Permissible Exposure Limit (PEL): People working in areas where silica dust is generated cannot be exposed to more than 50 micrograms per cubic meter of air (50 µg/m³), averaged over an 8-hour workday.
• Action Level: When levels exceed 25 µg/m³, employers must implement exposure monitoring and control measures.
• Additional Regulations: A full list of OSHA standards for respirable crystalline silica can be found in OSHA Standard 1926.1153

Controlling Silica Dust

Reducing exposure to silica dust usually includes a combination of engineering and administrative controls, personal protective equipment and housekeeping practices.

Engineering controls to effectively minimize silica dust at the source include:

• Applying water to cutting, drilling, grinding or crushing surfaces to suppress dust and/or utilizing equipment with integrated water delivery systems.
• Utilizing equipment with vacuum systems that capture dust at the point of origin.
• Separating dust-generating processes from workers with enclosures and isolation.

Administrative controls to change the way work is done to reduce exposure include:

• Rotate work to limit the time each worker spends in high-exposure areas.
• Schedule dusty tasks during times when fewer workers are present.
• Provide training programs to ensure proper handling procedures.

Personal Protective Equipment (PPE) provide a critical last line of defense:

• Respirators: The minimum requirements when working around silica dust include an N95 NIOSH-approved respirator or higher filtration level half-face respirator with P100 filters, depending on the type of work performed and level of exposure.
• Protective clothing can prevent dust from adhering to workers’ clothing.
• Hygiene facilities, such as showers and clean changing areas can help to reduce contamination.

Housekeeping Practices

Avoid dry sweeping or using compressed air that can aerosolize the dust to clean up silica dust. Instead, consider using high efficiency particulate air (HEPA) vacuums and wet cleaning/wiping methods.

Remediating Areas Impacted by Silica Dust

Assessment and Planning

• Conduct air and surface sampling to determine contamination levels and the extent of impacts.
• Identify high-risk zones.
• Develop a remediation protocol based on regulatory requirements.

Containment

• Use physical barriers (i.e., plastic sheeting) to isolate the contaminated area.
• Implement negative air pressure environments if necessary to prevent dust migration.
• If applicable, seal all HVAC units and do not operate them during remediation.

Dust Suppression

• Mist or fogging systems may be used to suppress airborne particles before cleanup begins.
• Avoid dry disturbance of contaminated materials.

Cleaning

• Use HEPA vacuums to remove settled dust.
• Follow up with wet wiping or mopping using a non-dispersive cleaning agent.

Waste Handling

• Collect and dispose of silica-containing materials in accordance with local hazardous waste regulations.
• Label containers clearly to prevent accidental exposure during transport or disposal.

Verification and Clearance Testing

• Conduct post-remediation air and surface testing.
• Compare results against regulatory standards.
• If levels are acceptable, remove containment and resume normal operations.

Documentation

• Keep detailed records of exposure levels, remediation steps, equipment used, and final clearance results to ensure regulatory compliance.

How Can VERTEX Help?

VERTEX has a team of environmental professionals, including Certified Industrial Hygienists, with the expertise and experience to:

• Inspect silica dust contaminated properties
• Determine the extent of the impact and the necessary response activities
• Identify any potentially responsible parties
• Determine appropriate remedial efforts and the regulatory reporting necessary to correct the environmental condition
• Evaluate costs for reasonableness

VERTEX’s strategic nationwide locations allow us to mobilize on behalf of our clients to identify and mitigate challenges associated with pollution claims.

For more information, contact Ashton Gant, Project Manager II at agant@vertexeng.com or info@vertexeng.com.