What You Should Know About Silica Dust
What are the Damaging Effects of Silica Dust?
Silica dust is an extremely common, and potentially hazardous, mineral compound found throughout numerous industries and applications across the globe. It exists in nature primarily as quartz, although in many areas it is a major component in sand. In fact, it is the second most common mineral in the earth’s crust. Occupationally, it affects approximately 2.3 million individuals in the United States alone. Any occupation which involves the handling or use of rock, brick, or sand, or participates in drilling, quarrying, or tunneling carries the risk of silica exposure. Inhaling crystalline silica dust can lead to debilitating and fatal lung cancers and diseases, most notably silicosis.
What is Silicosis?
Silicosis is an occupational disease caused by exposure to dust from crystalline silica, one of the most common minerals on our planet. Silicosis is a progressive, disabling lung disease caused by breathing dust that contains particles of crystalline silica so small you can only see them with a microscope. Silicosis isn’t curable, and sadly, workers still die from the disease, but it’s preventable. The keys to prevention are simple, identify workplace activities that create crystalline silica dust and then either eliminate the dust, or control it so that workers aren’t exposed to it.
Furthermore, silicosis is a lung affliction caused by breathing dust which contains fine particles of crystalline silica. If silica particles are inhaled, they become embedded in the lungs. The lung tissues then react by developing fibrotic nodules and scarring around the trapped particles. The scar tissue makes the lungs hard and stiff. Finally, this scarring can greatly reduce the function of the lungs, making it difficult and sometimes painful to breathe.
Most importantly, silicosis comes in three forms:
Chronic silicosis: The most common form of the disease, it may go undetected for years in the early stages. Chest X-rays may not reveal an abnormality until after 15 or 20 years of exposure. If you believe you are overexposed to silica dust, visit a doctor who knows about lung diseases. The progress of silicosis can only be stopped; but cannot be cured.
Accelerated silicosis: This type of silicosis tends to develop between 5 and 10 years after an exposure to high concentrations of crystalline silica dust. Examinations through x-rays and symptoms are often similar or exactly the same as chronic silicosis, but appear faster and accelerate quickly (hence the name).
Acute silicosis: Acute silicosis appears relatively rapidly after exposure to extreme amounts crystalline silica dust. There are recorded cases of patients showing signs of acute silicosis mere weeks after exposure. In these cases, symptoms are disabling and develop very quickly, including shortness of breath, weight loss, cough, and often imminent death.
Because of its abundance in nature, the use of silica has been in practice since ancient times in various applications. Its health risks – those that come primarily silica exposure via dust inhalation – were first documented in 1700 by Dr. Bernardino Ramazzini (the man often credited with the advent of occupational medicine) when he recognized symptoms of silicosis in stone cutters.
In the early 1900s, Dr. Alice Hamilton saw the same connections between silicosis and the dust being inhaled by granite cutters. This discovery and the engineering demands that followed would set in motion an increased awareness of silica exposure dangers across the globe. Today, occupational health and safety agencies all across North America strictly enforce regulations which limit and protect workers from silica dust exposure.
Symptoms of Silicosis
Because many cases silicosis do not develop until several years after exposure, patients may be slow to experience symptoms. This is why respirable silica dust exposure is so dangerous – there is very little to inform a worker there’s a problem until it’s too late. Once developed, symptoms may include:
- Shortness of breath, worsened by physical exertion
- Persistent and severe cough
- Chest pain
- Bluish skin
- Rapid breathing
- Weight loss and lack of appetite
- Dark spots appearing in nail beds
Eventually, as the lungs’ ability to perform efficiently wanes, patients faced with silica exposure may require the support of oxygen-supplying or other respiration-assistance devices.
The three types of silicosis each affect the lungs in a slightly unique way:
Chronic silicosis will involve lung swelling and expansion of lymph nodes in the chest, which leads to difficulty breathing.
Patients of acute silicosis will experience severe inflammation of the lungs as well as the introduction of fluid, which creates severe loss of breath and lowered levels of blood oxygen.
The lungs of an accelerated silicosis patient will experience the same symptoms as chronic silicosis, except they will develop must faster.
Identifying hazardous activities: You may be using products or materials that contain crystalline silica and not even know it. If your workplace is dusty, or if you work with materials that produce dust, you should be concerned about silicosis and crystalline silica hazards.
Activities that could put workers at risk:
Manufacturing: Metal casting; Working with glass products; Ceramics, clay and pottery; Asphalt paving material; Cut stone and stone products; Abrasives; Paint and rubber products; Filtered food and beverages.
Construction: Chipping, hammering and drilling rock, Abrasive blasting; Crushing, loading, hauling and dumping rock; Cement work; Sawing, hammering, drilling, grinding, and chipping masonry or concrete; Demolition of concrete or masonry structures; Dry sweeping or using pressurized air to blow concrete, rock or sand dust.
How to eliminate or control crystalline silica dust hazards: Once the activities that expose workers to hazardous levels of crystalline silica have been identified, you need to eliminate the exposure or control it so that it’s not hazardous. Here are some suggestions.
In work activities where there’s a potential to eliminate silica exposure:
- The best way to eliminate exposure is to use materials that don’t contain crystalline silica. This is an example of the “engineering” approach to hazard control. There are a number of abrasive materials that can be used to eliminate crystalline silica exposure including metal or plastic shot, organic materials such as apricot pits and corn cobs and emery, garnet or glass beads
In work activities where exposure to silica can’t be eliminated:
Use Dust-Containment Systems
- Install dust-collection systems on machines that generate dust or using enclosed cabinets with gloved armholes to do hazardous tasks
- Use wet drilling or sawing methods to control dust. Remove dust and debris with a wet vacuum, or hose it down rather than blowing it around with compressed air or dry sweeping it
- Use local-exhaust ventilation systems to keep work areas dust free
- PPE such as respirators and dust masks can protect workers from hazards, but it doesn’t eliminate them. If the equipment fails, or it’s not appropriate for a particular job, workers can still be exposed
- If you work with materials containing crystalline silica, you should always practice good personal hygiene. Wash your hands before eating, drinking or smoking. Shower, if possible, and change into clean clothes before leaving the worksite. Never eat, drink, or use tobacco in abrasive blasting areas
There is no known cure for silicosis, but it is 100 percent preventable by utilizing OSHA silica exposure safety procedures. Treatment options are limited, as physicians ordinarily simply instruct workers to permanently remove themselves from exposure zones, avoid respiratory irritants, and quit smoking. Silicosis often comes with respiratory infections, so antibiotics may also be prescribed.
That said, the best way to avoid the horrific and debilitating consequences of silicosis is to prevent it from occurring altogether. Employers who are involved with the use and handling of silica in the workplace are required by law to install various measures to ensure worker exposure is below a dangerous level, and it is the workers’ responsibility to abide by those measures.
Engineering controls such as ventilation systems, work displacement, or substitution with an equal-yet-less-hazardous material may be used. Workers should comply with and respect any installed systems. Additionally, handling dust properly when it’s created is important. Dust should never be cleaned with air or other procedures which could reintroduce it into the breathable atmosphere.
If respiratory protection is required, workers must undergo thorough medical examinations to determine their safe compatibility with respirators, and be trained in how to use, store, and maintain them.
Most importantly, workers should use any on-site facilities provided to ensure silica dust does not cross contaminate. A change of clothes is critical to avoid carrying silica dust home with you on your work clothes.
Though silicosis shows no symptoms at first, the victim eventually has trouble breathing and develops a severe cough. Other symptoms include fatigue, loss of appetite, chest pains and fever. Only a complete work history, chest X-ray, and a lung-function test will determine whether a worker has the disease. If you think you may have silicosis should see a medical doctor who specializes in occupational medicine.
Safety Services Company is committed to helping employers in the U.S. and Canada provide safe and healthful workplaces for their employees through innovative OSHA silica training programs.
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