Silica Dust News

Silicon is natural and abundant in the earth's crust. Crystalline silica (also known as free silica), in fact, is the main component in rocks, granite, sand, sandstone, soil and other minerals. Contained in common building sources like cement, concrete, tiles, clay bricks and ceramic mediums, it is an ever-present threat to those who are exposed to its airborne particles.

Silica is not dangerous in its natural environment. However, once silica- containing materials are cut, drilled, or smashed, fine particles become airborne and therefore respirable. Silica dust is extremely light and can remain airborne for a long period of time. It can affect unsuspecting individuals as it travels distances in the air and remains undetected. Once inhaled, these particles penetrate deep into the lungs and begin their journey of damage.

Workplace exposure is the most common medium for contracting silica-related illnesses. Those workers involved in mining, tunneling, brick-making, glass manufacturing, granite cutting, blasting (with explosives), demolition work and road building are in a high risk category if precautions are not taken to protect the lungs throughout entire exposure periods.

Short term exposure to silica dust may cause symptoms of irritation in the nose, throat and eyes, not unlike a generalized allergic response to varying, aggravating environmental agents. An initial annoying cough may become dry and persistent. Excessive eye tearing and blinking may also be present, and ocular pain can occur as the dust settles in and about the eye. There is some correlation with corneal opacities, and therefore an actual decline in visual acuity, but this is not considered to be an absolute cause and effect link.

It is silicosis, once referred to as Potter's Rot, Grinder's Rot and Stonemason's Disease, that is the most clearly associated occupational and incurable lung disease resulting from exposure to respirable crystalline silica. As the toxic dust is inhaled, a strong inflammatory reaction takes place within the lungs. This leads to scarring. Macrophages (scavenger cells) release enzymes which are responsible for the actual scarring. Initially, the scarring resembles tiny lumps. However, over a period of time the lumps combine and merge, thus leading to both tissue thickening and even greater scarring (fibrosis). Scarring prevents normal oxygen transport to the blood, and breathing becomes difficult. Even if exposure to silica is discontinued, the disease process cannot reverse itself. In fact, fibrosis may continue to progress even after exposure to the dust has ceased. It is important to note, however, that when silicosis is diagnosed in its early phases, the process of decline can be retarded.

Silicosis is broken down into four basic classifications based on exposure amounts and durations. Diagnosis can determine the presence of Chronic (Classic) Silicosis, Complicated Silicosis, Accelerated Silicosis or Acute Silicosis. General silicosis symptoms may present themselves via a dry and chronic cough, increased production of phlegm, fever, difficulty breathing and sleeping, decreased appetite, chest pain, and blue tinted nails (indicative of oxygen deficiency).

More specific symptoms and explanations based on the actual classifying categories of silicosis are as follows:
Chronic (Classic) Silicosis

• May take 15 years or more to develop
• Lung impairment is mild
• Can progress to more advanced forms of illness
• Complicated Silicosis
• Weight loss
• Shortness of breath
• Fibrosis
• Tuberculosis risk increases

Accelerated Silicosis

• Presents after 5 to 10 years of extreme exposure
• May lead to rheumatoid arthritis and / or autoimmune disorders
• Progressive, massive fibrosis can ruin lung function

Acute Silicosis

• Presents after 6 months to 2 years of highly intense exposure
• Marked weight loss
• Severe breathing difficulties (shortness of breath)
• High Tuberculosis risk

Chronic Obstructive Pulmonary Disease (COPD) encompasses that group of illnesses responsible for blocking airflow and creating breathing-related complexities and problems. It is therefore a major risk factor when considering the debilitating effects of silica exposure. As victims develop smaller or clogged air passages, COPD becomes apparent. COPD is a major cause of illness, disability and sometimes death.

The following diseases, classified within the COPD category, are linked to silica exposure:

• Emphysema: characterized by alveoli destruction
• Chronic Bronchitis: inflammation and scarring of bronchi
• Asthma
• Lung Cancer

Severe complications and illness may occur throughout the body as the silica particles continue to wreak their havoc. We see complications and diseases of the kidney (glomerulonephritis), liver, and spleen, in addition to an unraveling of the immune system. As the immune system becomes more and more vulnerable the lungs lose efficiency with both respiratory function and their ability to battle bacteria and infection. That is why exposure to tuberculosis becomes such a threat. The bacteria cannot be handled effectively by the immune system any longer.

Heart attack is another grave concern due to the ever-present, and sometimes escalating, scar tissue present in the lungs. The compromised lungs force the heart to work harder, and as it strains and labors to circulate blood throughout the body it can become strained. Specifically, lung damage strains the right side of the heart and can lead to cor pulmonale, a type of heart failure.

A link may exist between respirable silica and connective tissue diseases such as scleroderma (a rare disorder leading to diseased or inflammatory changes of the skin, blood vessels, joints, skeletal muscles), or systemic lupus erythematosus (SLE). With lupus, an overly active immune system erroneously attacks good and healthy cells and tissues. This can result in rash, joint pain and organ damage. Silica dust may be a trigger that alters the recognition of useful, healthy cells and causes the body's immune system to turn on itself.

It has also been determined that there is an increased risk of developing Rheumatoid Arthritis (inflamed and highly painful joint lining due to autoimmune dysfunction) with silica exposure. Rheumatoid Arthritis, in turn, can lead to Caplan's Syndrome (also known as Rheumatoid pneumoconiosis), a disorder where the lungs become inflamed and scarred.

Sarcoidosis, an uncommon illness resulting from changes in the immune system, is also linked to silica inhalation. This granulomatous illness often originates in the lungs, but it ultimately affects different organs within the body. As tiny sand-like granulomas form, they expand and adhere to one another. The resulting lumps affect organ function. Generally more than one organ will be affected through both the active and non-active phases of the illness. Symptoms may remain mild or, in severe cases, result in death.

Silicosis and other related illnesses can be prevented with responsible precautions to reduce exposure. This can be achieved through the initial identification of environments that produce the silica dust and then by systematically eliminating exposure. Areas need to be cleaned with vacuums and wet sweepers. Cleaner air can be obtained through ventilation systems, monitoring and creating parameters for exposure time, education of workers in high risk environments (seminars, brochures, posters), mandatory respiratory protection (through the use of simple disposable masks and/ or actual respirators), protective clothing (which should be vacuumed and cleaned after exposure to dust), tools with dust collecting devices and water attachments when appropriate, on-site showers (to remove any silica particles from the hair and skin), and the implementation and routine testing of effective dust control systems. Whenever possible, of course, safer materials (silica substitutions) should be used.

Clearly, exposure to silica dust is extremely dangerous and can affect different body organs and systems. Risk increases as exposure increases. The exposure amount and duration determine just how disabling and detrimental the effects may be. It is imperative that measures be taken to protect the lungs of those who work with this material.