What is Silica?
Silica, also known as Silicon dioxide, is an oxide of silicon with the chemical formula SiO2, most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as synthetic product. Notable examples include fused quartz, fumed silica, silica gel, and aerogels. Silica is used in structural materials, microelectronics (as an electrical insulator), and as components in the food and pharmaceutical industries.
Silica Dust Exposure
Silica exposure may occur in a variety of industrial trades, including in the construction and manufacturing settings. Some occupational settings that may place workers at an increased risk of exposure to silica dust include the following:
· Construction work
· Glass manufacturing
· Ceramics work
· Steel industry work
· Stone cutting
· Tunnel working
· Coal mining
· Hard rock mining
According to the Occupational Safety and Health Administration (OSHA), breathing in silica dust can lead to a debilitating, irreversible, and a potentially fatal respiratory disease called silicosis, as well as a number of other health conditions and cancers. OSHA’s Respirable Crystalline Silica standard for construction requires employers to limit worker exposures to respirable crystalline silica and to take other steps to protect workers.
Health Effects of Silica Dust Exposure
Inhaling silica dust is toxic and can lead to severe inflammation of the lung tissue, silicosis, bronchitis, lung cancer, and systemic autoimmune diseases, such as lupus and rheumatoid arthritis.
Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of nodular lesions in the upper lobes of the lungs. It is a type of pneumoconiosis. Silicosis (particularly the acute form) is characterized by shortness of breath, cough, fever, and cyanosis (bluish skin). It may often be misdiagnosed as pulmonary edema (fluid in the lungs), pneumonia, or tuberculosis.
Because chronic silicosis is slow to develop, signs and symptoms may not appear until years after exposure. Signs and symptoms include:
- Dyspnea (shortness of breath) exacerbated by exertion
- Cough, often persistent and sometimes severe
- Tachypnea (rapid breathing) which is often labored,
- Loss of appetite and weight loss
- Chest pain
- Gradual darkening of skin (blue skin)
- Gradual dark shallow rifts in nails eventually leading to cracks as protein fibers within nail beds are destroyed.
In advanced cases, the following may also occur:
- Cyanosis, pallor along upper parts of body (blue skin)
- Cor pulmonale (right ventricle heart disease)
- Respiratory insufficiency
Patients with silicosis are particularly susceptible to tuberculosis (TB) infection—known as silicotuberculosis. The reason for the increased risk—3 fold increased incidence—is not well understood. Even workers with prolonged silica exposure, but without silicosis, are at a similarly increased risk for TB.
Pulmonary complications of silicosis also include chronic bronchitis and airflow limitation, non-tuberculous Mycobacterium infection, fungal lung infection, compensatory emphysema, and pneumothorax. There are some data revealing an association between silicosis and certain autoimmune diseases, including nephritis,scleroderma, and systemic lupus erythematosus, especially in acute or accelerated silicosis.
In 1996, the International Agency for Research on Cancer (IARC) reviewed the medical data and classified crystalline silica as “carcinogenic to humans.” Numerous subsequent studies have been published confirming this risk.
Types of Silicosis
Classification of silicosis is determined according to the disease’s severity, onset, and rapidity of progression. These include:
Chronic simple silicosis
Usually resulting from long-term exposure (10 years or more) to relatively low concentrations of silica dust and usually appearing 10–30 years after first exposure.This is the most common type of silicosis. Patients with this type of silicosis, especially early on, may not have obvious signs or symptoms of disease, but abnormalities may be detected by x-ray. Chronic cough and exertional dyspnea (shortness of breath) are common findings. Radiographically, chronic simple silicosis reveals a profusion of small (<10 mm in diameter) opacities, typically rounded, and predominating in the upper lung zones.
Silicosis that develops 5–10 years after first exposure to higher concentrations of silica dust. Symptoms and x-ray findings are similar to chronic simple silicosis, but occur earlier and tend to progress more rapidly. Patients with accelerated silicosis are at greater risk for complicated disease, including progressive massive fibrosis (PMF).
Silicosis can become “complicated” by the development of severe scarring (progressive massive fibrosis, or also known as conglomerate silicosis), where the small nodules gradually become confluent, reaching a size of 1 cm or greater. PMF is associated with more severe symptoms and respiratory impairment than simple disease. Silicosis can also be complicated by other lung disease, such as tuberculosis, non-tuberculous mycobacterial infection, and fungal infection, certain autoimmune diseases, and lung cancer. Complicated silicosis is more common with accelerated silicosis than with the chronic variety.
Silicosis that develops a few weeks to 5 years after exposure to high concentrations of respirable silica dust. This is also known as silicoproteinosis. Symptoms of acute silicosis include more rapid onset of severe disabling shortness of breath, cough, weakness, and weight loss, often leading to death. The x-ray usually reveals a diffuse alveolar filling with air bronchograms, described as a ground-glass appearance, and similar to pneumonia, pulmonary edema, alveolar hemorrhage, and alveolar cell lung cancer.
If you or a loved one has been diagnosed with a silica-related disease, contact the offices of DuBose Law Firm, PLLC today to schedule your free consultation by calling (888) 295-3943 or firstname.lastname@example.org. We provide over 20 years of experience litigating occupational lung disease cases, and our attorneys will provide you with a no-cost, no-obligation review of your case and explain the legal options available to you. We are standing by and ready to help.