Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

MAGNESIUM ALUMINOSILICATE (SMECTITE)

NFPA

PRODUCT USE

Manufacture of refractory materials.

SYNONYMS

"silicic acid, aluminum magnesium salt", "aluminosilicic acid, magnesium salt",
"aluminium magnesium oxide silicate", "aluminium magnesium silicate", "magnesium silicate
aluminate", alumino-silicate, "smectite group minerals", "smectite clay, hyrdogen form",
"Veegum T"

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

EMERGENCY OVERVIEW

RISK

Harmful: danger of serious damage to health by prolonged exposure through
inhalation.

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  The material has NOT been classified as "harmful by ingestion". This is because of the lack of corroborating animal or human evidence. 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, unintentional ingestion is not thought to be cause for concern.  

EYE

  Although the material is not thought to be an irritant, direct contact with the eye may cause transient discomfort characterized by tearing or conjunctival redness (as with windburn). Slight abrasive damage may also result. The material may produce foreign body irritation in certain individuals.  

SKIN

  Entry into the blood-stream, through, for example, cuts, abrasions or lesions, may produce systemic injury with harmful effects. Examine the skin prior to the use of the material and ensure that any external damage is suitably protected.  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.  

INHALED

  Inhalation of dusts, generated by the material during the course of normal handling, may be damaging to the health of the individual.  The material is not thought to produce respiratory irritation (as classified using animal models). Nevertheless inhalation of dusts, or fume, especially for prolonged periods, may produce respiratory discomfort and occasionally, distress.  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.  

CHRONIC HEALTH EFFECTS

  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.  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).  Limited evidence suggests that repeated or long-term occupational exposure may produce cumulative health effects involving organs or biochemical systems.  This material can cause serious damage if one is exposed to it for long periods. It can be assumed that it contains a substance which can produce severe defects. This has been demonstrated via both short- and long-term experimentation.  Exposure to large doses of Aluminum has been connected with the degenerative brain disease Alzheimer's Disease.