What is ‘Silica’?
Silica (silicon dioxide, SiO2) is a naturally occurring mineral found in sand, rock, and quartz. It’s the most abundant mineral in the Earth’s crust and occurs in three main crystalline varieties, including quartz, tridymite, and cristobalite. The informal use of the word ‘Silica’ can refer to any combination of the various minerals that may contain silicon Dioxide.
Where is Silica Dust found?
Silica dust is released during many industrial processes, including:
- Sandblasting
- Countertop manufacturing
- Concrete resurfacing
It can be a by-product to many manufacturing, industrial and construction processes anytime varieties of quartz, granite and other such minerals are used as a material or in a manufacturing process.
Why Is Silica Dust Harmful?
Silica dust poses significant health risks when inhaled as dust. Prolonged exposure to silica can lead to serious conditions like:
- Silicosis (a lung disease)
- Lung cancer
- Other respiratory illnesses
Recognizing the critical need to monitor and control silica exposure in the workplace is essential for occupational safety and health.
When did silica dust become a worker safety hazard?
Silica exposure has been a documented health risk since ancient times. Evidence suggests pre-Egyptian stoneworkers used damp cloths to filter dust while cutting stone blocks. More recently, in 2023 OSHA, has placed more emphasis on preventative measures in using protection when working with silica dust.
Where does Silica exposure occur?
Silica exposure can occur directly inside manufacturing zones / areas , as well as anywhere in the general work environment where cross-contamination may occur. Ventilation, windows, doors and improper function of engineering controls can lead to greater exposure to silica dust and higher airborne concentrations.
How is Silica exposure tested for?
There are three main ways to test for silica dust:
- Area air sampling: Measures silica levels in the general environment.
- Personal exposure sampling: Uses a cassette worn by workers to monitor their breathing zone.
- Surface sampling: Collects samples from AC vents and work surfaces.
Who sets the limits on Silica?
Exposure limits are set by various regulatory and advisory bodies in the US, including:
- OSHA (Occupational Safety and Health Administration)
- NIOSH (National Institute for Occupational Safety and Health)
- ACGIH (American Conference of Governmental Industrial Hygienists)
What is NIOSH 7500?
NIOSH 7500 refers to a specific analytical method developed by the National Institute for Occupational Safety and Health (NIOSH) for the testing of silica dust in the air. This method plays a pivotal role in occupational health, helping to assess workers’ exposure to silica and enforce safety standards.
How are samples collected and analyzed?
Airborne particles are collected using a pump and cyclone separator and either measured as ambient air or a personal exposure. Samples are then analyzed in a lab to quantify silica content using methods like X-ray diffraction (XRD) or infrared (IR) spectrometry.
Silica Dust – Final Thoughts
Silica dust exposure has been a worker hazard for centuries. Products containing silica are currently, and will most likely continue, to be a part of our everyday lives for Millenia to come. Understanding the risks associated with silica can assist both workers and employers follow regulations and prevent unnecessary exposure. If you or your company have silica testing needs, Full Spectrum Environmental can perform testing and inspections relating to occupant exposure. More information can be found under our Air Quality Testing page.