Crystalline silica is an important industrial material found abundantly in the earth’s crust. Quartz, the most common form of silica, is a component of sand, stone, rock, concrete, brick, block, and mortar. Materials containing quartz are found in a wide variety of workplaces.
Silica dust is hazardous when very small (respirable) particles are inhaled. These respirable dust particles can penetrate deep into the lungs and cause disabling and sometimes fatal lung diseases, including silicosis and lung cancer, as well as kidney disease, generally over a period of time.
Occupational exposure to respirable crystalline silica occurs when cutting, sawing, drilling, and crushing of concrete, brick, ceramic tiles, rock, and stone products. Occupational exposure also occurs in operations that process or use large quantities of sand, such as foundries and the glass, pottery and concrete products industries. OSHA estimates that more than 2.3 million workers in the United States are potentially exposed to dust containing crystalline silica with nearly 90% of those workers employed in the construction industry.
Industries and operations in which exposure to crystalline silica can occur include, but are not limited to:
- Glass products
- Pottery products
- Structural clay products
- Concrete products
- Dental laboratories
- Paintings and coatings
- Jewelry production
- Refractory products
- Ready-mix concrete
- Cut stone and stone products
- Refractory installation and repair
- Railroad track maintenance
- Hydraulic fracturing for gas and oil
- Abrasive blasting in: Maritime work, Construction, General industry
Over the next few weeks, we will be discussing methods of controlling silica in the workplace for certain tasks and activities. There are 5 primary ways or controls when workers are exposure to hazards which can help eliminated or controlled that hazard, (such as silica).
- Engineering controls
- Administrative controls
- Personal Protective Equipment controls
Eliminating the hazard—physically removing it—is the most effective hazard control. For example, if employees must work high above the ground, the hazard can be eliminated by moving the piece they are working on to ground level to eliminate the need to work at heights.
Substitution, the second most effective hazard control, involves replacing something that produces a hazard (similar to elimination) with something that does not produce a hazard—for example, replacing lead-based paint with titanium white. To be an effective control, the new product must not produce another hazard. Because airborne dust can be hazardous, if a product can be purchased with a larger particle size, the smaller product may effectively be substituted with the larger product
An effective means of controlling hazards is engineered controls. These do not eliminate hazards, but rather isolate people from hazards. Costs of engineered controls tend to be higher than less effective controls in the hierarchy, however they may reduce future costs. For example, a crew might build a work platform rather than purchase, replace, and maintain fall arrest equipment. "Enclosure and isolation" creates a physical barrier between personnel and hazards, such as using remotely controlled equipment. Fume hoods can remove airborne contaminants as a means of engineered control.
Administrative controls are changes to the way people work. Examples of administrative controls include procedure changes, employee training, and installation of signs and warning labels (such as those found on the Safety Data Sheets). Administrative controls do not remove hazards, but limit or prevent people's exposure to the hazards, such as completing road construction at night when fewer people are driving.
Personal Protective Equipment:
Personal protective equipment (PPE) includes gloves, Tvek clothing, respirators, hard hats, safety glasses, high-visibility clothing, and safety footwear. PPE is the least effective means of controlling hazards because of the high potential for damage to render PPE ineffective. Additionally, some PPE, such as respirators, increase physiological effort to complete a task and, therefore, may require medical examinations to ensure workers can use the PPE without risking their health.
When you are exposed to silica, start thinking about how you can implement the higher level of control - eliminate. Sometimes it is impossible to "eliminate", but there are other controls you could use that might work. If you have an idea on how best to tackle the problem, bring it to the attention of your supervisor/manager. Working together to create a safe work environment.
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