The Hazards of Free Silicon, Why Do We Need to Use Dust-Free Sand?

What are the hazards of crystalline silica?

Silica exposure remains a serious threat to nearly 2 million U.S. workers, including more than 100,000 workers in high-risk jobs such as abrasive blasting, foundry work, stonecutting, rock drilling, quarry work, and tunneling. The seriousness of the health hazards associated with silica exposure is demonstrated by the fatalities and disabling illnesses that continue to occur in sandblasters and rock drillers. Crystalline silica has been classified as a human lung carcinogen. Additionally, breathing crystalline silica dust can cause silicosis, which can be disabling or even fatal in severe cases. The respirable silica dust enters the lungs and causes scar tissue formation, thus reducing the lungs’ ability to take in oxygen. There is no cure for silicosis. Since silicosis affects lung function, it makes one more susceptible to lung infections like tuberculosis. Also, smoking causes lung damage and adds to the damage caused by breathing silica dust.

What is crystalline silica?

Crystalline silica is a primary component of soil, sand, granite, and many other minerals. Quartz is the most common form of crystalline silica. Cristobalite and tridymite are two different forms of crystalline silica. All three forms may become respirable size particles when workers chip, cut, drill, or grind objects that contain crystalline silica.

What are the symptoms of silicosis?

Chronic/classic silicosis, the most common, occurs after 15–20 years of moderate to low exposures to respirable crystalline silica. Symptoms associated with chronic silicosis may or may not be obvious; therefore, workers need to have a chest x-ray to determine if there is lung damage. As the disease progresses, the worker may experience shortness of breath upon exercising and have clinical signs of poor oxygen/carbon dioxide exchange. In the later stages, the worker may experience fatigue, extreme shortness of breath, chest pain, or respiratory failure. Accelerated silicosis can occur after 5–10 years of high exposure to respirable crystalline silica. Symptoms include severe shortness of breath, weakness, and weight loss. The onset of symptoms takes longer than in acute silicosis.
Acute silicosis occurs after a few months or two years following exposures to extremely high respirable crystalline silica concentrations. Acute silicosis symptoms include severe disabling shortness of breath, weakness, and weight loss, leading to death.

Where are general industry employees exposed to crystalline silica dust?

The most severe exposures to crystalline silica result from abrasive blasting, which is done to clean and smooth irregularities from molds, jewelry, and foundry castings, finish tombstones, etch or frost glass, or remove paint, oils, rust, or dirt from objects needing to be repainted or treated.

What can employers/employees do to protect against exposures to crystalline silica?

• Replace crystalline silica materials with safer substitutes whenever possible.
• Provide engineering or administrative controls, where feasible, such as local exhaust ventilation and blasting cabinets. Where necessary, to reduce exposures below the PEL, use protective equipment or other protective measures.
• Use all available work practices to control dust exposures, such as water sprays.
• Wear only an N95 NIOSH certified respirator if respirator protection is required. Do not alter the respirator. Do not wear a tight-fitting respirator with a beard or mustache that prevents a good seal between the respirator and the face.
• Wear only a Type CE abrasive-blast supplied-air respirator for abrasive blasting.
• Wear disposable or washable work clothes and shower if facilities are available. Vacuum the dust from your clothes or change into clean clothing before leaving the worksite.
• Participate in training, exposure monitoring, and health screening and surveillance programs to monitor any adverse health effects caused by crystalline silica exposures.
• Be aware of the operations and job tasks creating crystalline silica exposures in your workplace environment and know how to protect yourself.
• Be aware of the health hazards related to exposures to crystalline silica. Smoking adds to the lung damage caused by silica exposures.
• Do not eat, drink, smoke, or apply cosmetics in areas where crystalline silica dust is present. Wash your hands and face outside of dusty areas before performing any of these activities.
• Remember: If it’s silica, it’s not just dust.