What is silica and what are the possible dangers of working with silica?

Silica may be of several distinct types. For example, quartz is a crystalline form of silica and is the most common mineral in the earth’s crust. When rock containing quartz is chipped, hammered, drilled, crushed, loaded, hauled, or dumped, small particles of silica are released into the air and can be inhaled by workers.

Silica sand containing quartz is used in sandblasting equipment to clean surfaces. The outsides of buildings and bridges and the insides of storage tanks and pipes are some of the surfaces that are cleaned by sandblasting.

The silica sand used in sandblasting breaks into fine particles that stay in the air (Figure 1). If these particles are small enough to be inhaled deeply into the lungs, they are known as respirable crystalline silica. Inhaling these fine silica particles causes more lung damage than inhaling larger particles. This process causes rapid and severe forms of silicosis in sandblasters.

What is silicosis?

When workers inhale crystalline silica, the lung develops scar tissue around the silica particles. This process results in a lung disease known as silicosis. As more lung tissue is damaged by silica dust, breathing becomes more difficult, chest pain occurs, and death may result. Silicosis patients suffer shortness of breath, fever, and cyanosis. Some patients are diagnosed incorrectly as having pulmonary edema, pneumonia, or other lung diseases.

The three types of silicosis are as follows:

Chronic silicosis, which occurs after 10 or more years of exposure to low concentrations of crystalline silica.

Accelerated silicosis, which occurs 5 to 10 years after exposure to high concentrations of crystalline silica.

Acute silicosis, which occurs a few weeks to 5 years after exposure to very high concentrations of crystalline silica.

How many workers are exposed to dusts containing crystalline silica?

More than 2 million U.S. workers are potentially exposed to dusts containing crystalline silica. More than 100,000 of them are in high-risk occupations, including sandblasting. Most sandblasters work in construction and shipbuilding. Workers may be exposed to crystalline silica in many other industries, including surface and underground mining, pottery, drywall hanging, glassmaking, foundry work, quarry work, work with sandblasting materials, agriculture, and automotive repair.

What fields of occupational health protect workers from occupational hazards?

Industrial hygiene is the science of recognizing, evaluating, and controlling hazards in the workplace and environment. Industrial hygiene practices protect workers from hazards. Other professionals important for protecting workers’ health include occupational health physicians and nurses as well as engineers.

What practices are used to protect workers from silicosis?

Industrial hygiene practices are used to protect workers from silicosis and other workplace hazards. These practices include the use of substitution, engineering controls, work practices, respiratory protection, and air monitoring. Employers are responsible for implementing these practices when they are needed to provide safe and healthful workplaces.