Occupational exposures to respirable crystalline silica occur in a variety of industries and occupations because of its extremely common natural occurrence and the wide uses of materials and products that contain it. At least 1.7 million U.S. workers are potentially exposed to respirable crystalline silica [NIOSH 1991], and many are exposed to concentrations that exceed limits defined by current regulations and standards.
Silicosis, usually a nodular pulmonary fibrosis, is the disease most associated with exposure to respirable crystalline silica. Although the reported mortality associated with silicosis has declined over the past several decades, many silicosis associated deaths still occur (nearly 300 deaths were reported each year during the period 1992-1995) [NIOSH 1996a; Althouse 1998]. In addition, the number of silicosis associated deaths among persons aged 15 to 44 has not declined substantially [CDC 1998a,b]. An unknown number of workers also continue to die from silica-related diseases such as pulmonary tuberculosis (TB), lung cancer, and scleroderma. The number of cases of silicosis and silica-related diseases in the United States today is unknown.
Source: http://www.cdc.gov/niosh/docs/2002-129/02-129a.html
Showing posts with label silicosis. Show all posts
Showing posts with label silicosis. Show all posts
Friday, August 14, 2009
Monday, August 3, 2009
Symptoms of Silicosis as Per OSHA
What are the symptoms of silicosis?
Silicosis is classified into three types: chronic /classic, accelerated, and acute.
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 exposures 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 as long as 2 years following exposures to extremely high concentrations of respirable crystalline silica. Symptoms of acute silicosis include severe disabling shortness of breath, weakness, and weight loss, which often leads to death.
Source: http://www.osha-safety.org/osha_crystalline_silica.asp
Silicosis is classified into three types: chronic /classic, accelerated, and acute.
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 exposures 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 as long as 2 years following exposures to extremely high concentrations of respirable crystalline silica. Symptoms of acute silicosis include severe disabling shortness of breath, weakness, and weight loss, which often leads to death.
Source: http://www.osha-safety.org/osha_crystalline_silica.asp
Friday, July 31, 2009
HEALTH EFFECTS OF CRYSTALLINE SILICA EXPOSURE
Description of Silicosis
When workers inhale crystalline silica, the lung tissue reacts by developing fibrotic nodules and scarring around the trapped silica particles [Silicosis and Silicate Disease Committee 1988]. This fibrotic condition of the lung is called silicosis. If the nodules grow too large, breathing becomes difficult and death may result. Silicosis victims are also at high risk of developing active tuberculosis [Myers et al. 1973; Sherson and Lander 1990; Bailey et al. 1974].
A worker's lungs may react more severely to silica sand that has been freshly fractured (sawed, hammered, or treated in a way that produces airborne dust) [Vallyathan et al. 1988]. This factor may contribute to the development of acute and accelerated forms of silicosis.
Types of Silicosis
A worker may develop any of three types of silicosis, depending on the airborne concentration of crystalline silica:
Initially, workers with silicosis may have no symptoms. As silicosis progresses, there may be difficulty in breathing and other chest symptoms such as cough. Infectious complications may cause fever, weight loss, and night sweats. Severe mycobacterial or fungal infections can complicate silicosis and may be fatal [Ziskind et al. 1976; Owens et al. 1988; Bailey et al. 1974]. Fungal or mycobacterial infections are believed to result when the lung cells (macrophages) that fight these infections are overwhelmed with silica dust and are unable to kill mycobacteria and other organisms [Allison and Hart 1968; Ng and Chan 1991]. About half of the mycobacterial infections are caused by Mycobacterium tuberculosis (TB), with the other half caused by M. kansasii and M. avium-intracellulare [Owens et al. 1988]. Nocardia and Cryptococcus may also cause infections in silicosis victims [Ziskind et al. 1976].
Medical evaluations of silicosis victims usually show the lungs to be filled with silica crystals and a protein material [Owens et al. 1988; Buechner and Ansari 1969]. Pulmonary fibrosis (fibrous tissue in the lung) may or may not develop in acute cases of silicosis, depending on the time between exposure and onset of symptoms.
Furthermore, evidence indicates that crystalline silica is a potential occupational carcinogen [NIOSH 1988; IARC 1987; DHHS 1991], and NIOSH is reviewing the data on carcinogenicity.
Source: http://www.cdc.gov/niosh/consilic.html
When workers inhale crystalline silica, the lung tissue reacts by developing fibrotic nodules and scarring around the trapped silica particles [Silicosis and Silicate Disease Committee 1988]. This fibrotic condition of the lung is called silicosis. If the nodules grow too large, breathing becomes difficult and death may result. Silicosis victims are also at high risk of developing active tuberculosis [Myers et al. 1973; Sherson and Lander 1990; Bailey et al. 1974].
A worker's lungs may react more severely to silica sand that has been freshly fractured (sawed, hammered, or treated in a way that produces airborne dust) [Vallyathan et al. 1988]. This factor may contribute to the development of acute and accelerated forms of silicosis.
Types of Silicosis
A worker may develop any of three types of silicosis, depending on the airborne concentration of crystalline silica:
- Chronic silicosis, which usually occurs after 10 or more years of exposure to crystalline silica at relatively low concentrations
- Accelerated silicosis, which results from exposure to high concentrations of crystalline silica and develops 5 to 10 years after the initial exposure
- Acute silicosis, which occurs where exposure concentrations are the highest and can cause symptoms to develop within a few weeks to 4 or 5 years after the initial exposure [Peters 1986; Ziskind et al. 1976]
Initially, workers with silicosis may have no symptoms. As silicosis progresses, there may be difficulty in breathing and other chest symptoms such as cough. Infectious complications may cause fever, weight loss, and night sweats. Severe mycobacterial or fungal infections can complicate silicosis and may be fatal [Ziskind et al. 1976; Owens et al. 1988; Bailey et al. 1974]. Fungal or mycobacterial infections are believed to result when the lung cells (macrophages) that fight these infections are overwhelmed with silica dust and are unable to kill mycobacteria and other organisms [Allison and Hart 1968; Ng and Chan 1991]. About half of the mycobacterial infections are caused by Mycobacterium tuberculosis (TB), with the other half caused by M. kansasii and M. avium-intracellulare [Owens et al. 1988]. Nocardia and Cryptococcus may also cause infections in silicosis victims [Ziskind et al. 1976].
Medical evaluations of silicosis victims usually show the lungs to be filled with silica crystals and a protein material [Owens et al. 1988; Buechner and Ansari 1969]. Pulmonary fibrosis (fibrous tissue in the lung) may or may not develop in acute cases of silicosis, depending on the time between exposure and onset of symptoms.
Furthermore, evidence indicates that crystalline silica is a potential occupational carcinogen [NIOSH 1988; IARC 1987; DHHS 1991], and NIOSH is reviewing the data on carcinogenicity.
Source: http://www.cdc.gov/niosh/consilic.html
Thursday, July 30, 2009
Silica, Crystalline, Silicosis Safety Issues
Recognizing potential hazards is key in preventing and minimizing the effects of silica exposure. Silicosis is a disabling, nonreversible and sometimes fatal lung disease caused by overexposure to respirable crystalline silica. The following references aid in recognizing crystalline silica hazards and health effects.
What is crystalline silica?
Crystalline silica is a basic component of soil, sand, granite, and many other minerals. Quartz is the most common form of crystalline silica. Cristobalite and tridymite are two other 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 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 rockdrillers. Crystalline silica has been classified as a human lung carcinogen. Additionally, breathing crystalline silica dust can cause silicosis, which in severe cases can be disabling, or even fatal. The respirable silica dust enters the lungs and causes the formation of scar tissue, 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. In addition, smoking causes lung damage and adds to the damage caused by breathing silica dust.
Source: www.OSHA.gov
What is crystalline silica?
Crystalline silica is a basic component of soil, sand, granite, and many other minerals. Quartz is the most common form of crystalline silica. Cristobalite and tridymite are two other 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 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 rockdrillers. Crystalline silica has been classified as a human lung carcinogen. Additionally, breathing crystalline silica dust can cause silicosis, which in severe cases can be disabling, or even fatal. The respirable silica dust enters the lungs and causes the formation of scar tissue, 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. In addition, smoking causes lung damage and adds to the damage caused by breathing silica dust.
Source: www.OSHA.gov
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