MAGNESIUM ALUMINOSILICATE (CORDIERITE)
Flammability | 0 | |
Toxicity | 2 | |
Body Contact | 1 | |
Reactivity | 0 | |
Chronic | 2 | |
SCALE: Min/Nil=0 Low=1 Moderate=2 High=3 Extreme=4 |
Manufacture of refractory materials.
(Mg2[Al4O3(SiO3)3])Al4O18Si5.2Mg, "Al3(Mg, Fe)2Si5AlO8", "magnesium aluminium silicate",
alumino-silicate
Harmful: danger of serious damage to health by prolonged exposure through
inhalation.
Although ingestion is not thought to produce harmful effects, the material may still be damaging to the health of the individual following ingestion, especially where pre- existing organ (e.g. liver, kidney) damage is evident. Present definitions of harmful or toxic substances are generally based on doses producing mortality (death) rather than those producing morbidity (disease, ill-health). Gastrointestinal tract discomfort may produce nausea and vomiting. In an occupational setting however, ingestion of insignificant quantities is not thought to be cause for concern. Considered an unlikely route of entry in commercial/industrial environments.
Although the material is not thought to be an irritant, direct contact with the eye may produce transient discomfort characterized by tearing or conjunctival redness (as with windburn). The dust may produce eye discomfort causing smarting, pain and redness.
The material is not thought to produce adverse health effects or skin irritation following contact (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable gloves be used in an occupational setting.
The material is not thought to produce adverse health effects or irritation of the respiratory tract (as classified using animal models). Nevertheless, good hygiene practice requires that exposure be kept to a minimum and that suitable control measures be used in an occupational setting. Persons with impaired respiratory function, airway diseases and conditions such as emphysema or chronic bronchitis, may incur further disability if excessive concentrations of particulate are inhaled. Used, fired refractory materials are potentially more harmful than new refractories. Silica containing materials when exposed to high temperatures maybe devitrified (i.e. converted or part converted to crystalline forms) - this may present a higher hazard if inhaled. Crystalline silicas are more likely to produce lung changes (fibrosis) and have a much lower occupational exposure levels (OELs) than non crystalline silicas. Exposure to fired refractories is more likely when repairing, rebuilding or demolishing old structures. Devitrified, after-service alkaline earth silicate (AES) wools and refractory ceramic fibres (RCF) insulation containing crystalline silica, show no adverse reactions in toxicity assays. CMS fibres heated to 1000 deg. C. for 2 weeks were not cytotoxic to macrophage-like cells at concentrations up to 320 ug/cm2. In the same test, samples of crystalline quartz were significantly active at 20 ug/cm2. These findings are consistent with IARC's evaluation, which states "Crystalline silica inhaled in the form of quartz or cristobalite from occupational sources is carcinogenic to humans (Group 1)" and additionally notes, in respect of devitrified wools and fibres that "carcinogenicity in humans was not detected in all industrial circumstances studied. Carcinogenicity may be dependent on inherent characteristics of the crystalline silica or on external factors affecting its biological activity or distribution of its polymorphs" (IARC Monograph Vol 68, 1997). Acute silicosis occurs under conditions of extremely high silica dust exposure particularly when the particle size of the dust is small. The disease is rapidly progressive and spreads widely through the lungs within months of the initial exposure and causing deaths within 1 to 2 years.
Primary route of exposure is usually by inhalation of generated dust. Long term exposure to high dust concentrations may cause changes in lung function i.e. pneumoconiosis; caused by particles less than 0.5 micron penetrating and remaining in the lung. Prime symptom is breathlessness; lung shadows show on X-ray. Prolonged or repeated skin contact may cause drying with cracking,irritation and possible dermatitis following. Chronic dust inhalation has been associated with lung disease. [NIOSHTIC] Repeated exposures, in an occupational setting, to high levels of fine- divided dusts may produce a condition known as pneumoconiosis which is the lodgement of any inhaled dusts in the lung irrespective of the effect. This is particularly true when a significant number of particles less than 0.5 microns (1/50,000 inch), are present. Lung shadows are seen in the X-ray. Symptoms of pneumoconiosis may include a progressive dry cough, shortness of breath on exertion, increased chest expansion, weakness and weight loss. As the disease progresses the cough produces a stringy mucous, vital capacity decreases further and shortness of breath becomes more severe. Pneumoconiosis is the accumulation of dusts in the lungs and the tissue reaction in its presence. It is further classified as being of noncollagenous or collagenous types. Noncollagenous pneumoconiosis, the benign form, is identified by minimal stromal reaction, consists mainly of reticulin fibres, an intact alveolar architecture and is potentially reversible. Exposure to large doses of Aluminum has been connected with the degenerative brain disease Alzheimer's Disease. Crystalline silicas may produce long term adverse effects. Crystalline silicas activate the inflammatory response of white blood cells after they injure the lung epithelium. Chronic exposure to crystalline silicas reduce lung capacity and predispose to chest infections. A large part of the crystals accumulates in the lungs. Silicosis can occur, a condition where irreversible scarring of the lung occurs. Symptoms do not appear until months to years after exposure. Smoking increases this risk. Most simple cases of silicosis do not produce symptoms, but they can progress and eventually cause a tuberculosis-like syndrome which can be fatal. When silicosis is advanced, there is an increased risk of lung cancer and lymphoma. Laws in some areas require those exposed to silica to be under health surveillance.