There is a general lack of awareness about the silica hazards, such as silicosis and the sources of silica exposure on the worksite. According to the CDC, more than 1 million U.S. workers are exposed to crystalline silica (free silica).
Overexposure to crystalline silica can cause silicosis, a disabling lung disease, and other health conditions.
Hazards
Sand, rock, and soil are the most common materials that contain silica. The most common form of crystalline silica is known as quartz. Inhalation of airborne dust containing crystalline silica can occur in various settings: mining, quarrying, and stone cutting; foundry operations; paint/sand-blasting; glass manufacturing and etching; and some types of construction work. When might you expect silica exposure?
- During work with dry sand, quartz, or clay that contains silica
- During the demolition of concrete, brick, and mortar
- During drilling of quartz-containing rock, clay, or sandy soil
- During dry sweeping of concrete, rock, clay, or sand dust
Inhalation of crystalline silica can lead to chronic or accelerated silicosis. Chronic silicosis, the most common form of the disease, usually occurs after ten or more years of overexposure. As silicosis progresses, symptoms such as severe cough and shortness of breath follow physical exertion.
Controls
Without adequate dust controls, construction workers may develop silicosis, which extends over a period of years. There are many things that employers and workers can do to help prevent silica exposure, including:
- Control overall dust exposures by minimizing the dust around work areas
- Substitute less hazardous abrasive-blasting materials for those containing crystalline silica
- Install engineering controls (local exhaust ventilation) and containment methods (blast-cleaning machines and cabinets) to prevent dust from being released into the air
- Train workers about the health effects of silica dust and good work practices that reduce dust
- Wet down surfaces before clean-up
- Use vacuums with high-efficiency particulate air (HEPA) filters or wet-sweeping for clean-up
- Never dry sweep, or blow dust with compressed air
- Wear respirators, where necessary to Note: Ensure control measures are adequate and working avoid breathing dust
- Be aware that the highest silica concentrations may occur inside enclosed areas during tasks such as concrete or masonry sawing or abrasive blasting. Conduct a hazard assessment to determine the appropriate level of respiratory protection with the aid of the Safety Department
- Shower/wash-up and change into clean clothes before leaving the worksite
Examples from OSHA Table 1 (same as WA L&I):
Click here to view OSHA Exposure Table Guidelines.
The keys to preventing silica exposure and possible silicosis are to minimize the amount of silica-containing dust in the air and to avoid breathing silica-containing dust. Once it develops, there is no cure for the disease, but it is 100 percent preventable if employers and workers work together to minimize exposure.
