Crystalline Silica: Not Just Fun in the Sand
Although many of us like to spend our summers with our feet in the sand, we should all remember that one of the major components of sand can be a major health hazard for those that are exposed to it.
Crystalline silica is the second most common mineral in the Earth’s crust and is found all over the world. Silica actually can be in one of three forms - Quartz, Cristobalite, and Tridymite. Quartz is the most common form and is found in many of our everyday building materials.
When workers chip, grind, saw, or cut materials that contain silica, small “respirable” pieces can be made that can be easily inhaled. While larger pieces of silica are filtered out in our nose and trachea, respirable silica can continue down our respiratory tract and become lodged in our lungs. These microscopic particles are responsible for the health hazards associated with exposure to silica.
Between 1968 and 1992 approximately 20,000 employee deaths were associated with exposure to silica in the workplace. These deaths were caused by silicosis (a scarring of the lung tissue caused by silica), lung cancer, and kidney disease.
Silicosis is the most common disease associated with silica exposure. It can take 15-20 years to develop chronic silicosis with low to moderate exposures to silica, but it can take only a few months to a few years of high exposures to develop acute silicosis.
Because of the increased understanding of the health effects of silica exposure, OSHA introduced a new standard in 2017 to reduce employee exposures. Regulation 29 CFR 1926.1153, which goes into effect on September 23, 2017, contains many new requirements for the protection of employees who are exposed to silica:
- The Permissible Exposure Limit (PEL) will be reduced from 100 ug/m3 to 50 ug/m3 for an eight hour Time Weighted Average (TWA).
- Airborne silica exposures to the Action Level of 25ug/m3 will trigger closer employee monitoring to ensure that the PEL is not exceeded.
- Table 1 in the standard addresses specific work tasks with potential exposures to silica and the engineering and work practice controls required to reduce airborne particles.
- New medical monitoring criteria for those employees exposed above the PEL.
Do you want to know more about the new OSHA standard for silica? MEMIC customers in Maine can register to attend one of the Silica Training Workshops to be held by MEMIC Loss Control in Scarborough (August 29, 2017) or Bangor (September 26, 2017). Additional silica information can be found in our previous three-part silica standard Safety Net Post written by Luis Pieretti, PhD, CIH, CSP.
OSHA’s Silica webpage contains further information about the upcoming enforcement of this new standard, sampling methods, fact sheets, Table 1, and frequently asked questions.