Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

REFRACTORIES, FIBRES, ALUMINOSILICATE

NFPA

PRODUCT USE

Primarily used as thermal insulating material in the form of bulk fibres, blankets,
papers, boards, plug cones, ropes and tapes. One application is backup insulation in
melting and holding furnaces in ingot moulding. Other applications include lining, sealing
and packing joints in molten metal transfer troughs and insulation for expansion joints
and pit covers in furnaces.

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

EMERGENCY OVERVIEW

RISK

May cause CANCER.
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

  There is some evidence to suggest that this material can causeeye irritation and damage in some persons.  

SKIN

  All man-made mineral fibres, in common with their natural counterparts, may produce mild irritation and inflammation which results in itching or, in the case of certain sensitive individuals, a slight reddening of the skin. This is due to entirely to a mechanical reaction to the sharp, broken fibre ends and does not involve chemical or allergic effects. Itching and possible inflammation are mechanical reactions to coarse fibres greater than 5 micron in diameter These symptoms occur particularly in folds of skin around wrists, collars and waistbands. Perspiration aggravates the condition. Irritation is accentuated by fibre adhering to sweaty skin at elevated temperatures. Symptoms generally abate within a short time after exposure ceases. When products are handled continually, the skin itching often diminishes.  This material can cause inflammation of the skin oncontact in some persons.  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 may accentuate any pre-existing dermatitis condition.  Skin contact is not thought to have harmful health effects, however the material may still produce health damage following entry through wounds, lesions or abrasions.  The material is mildly abrasive and may produce discomfort which results in a temporary skin rash. Discomfort is accentuated by fiber adhering to sweaty skin at higher temperatures.  

INHALED

  There is some evidence to suggest that the material can cause respiratory irritation in some persons. The body's response to such irritation can cause further lung damage.  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.  The dust may produce upper respiratory tract discomfort. Nose and throat discomfort may be transitory. Cutting and trimming may result in fiber dislodgment and dust production.  

CHRONIC HEALTH EFFECTS

  Harmful: danger of serious damage to health by prolonged exposure through inhalation.  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.  Repeated or prolonged breathing of particles of respirable size may cause inflammation of the lungs leading to chest pain, difficult breathing, coughing and possible fibrotic changes in the lung. Pre-existing medical conditions, specifically bronchial hyperactivity or chronic bronchial or lung disease, may be aggravated by such exposure.  Pulmonary morbidity studies have been carried out amongst production workers exposed to refractory ceramic fibres (RCFs), in Europe and the USA. In the American study, pleural plaques(thickening along the chest wall) were reported in 2.9% of the workers examined. The plaques did not appear to cause any adverse symptoms and did not develop into disease or appear to produce disability.Pleural plaques seem to show a relationship with the following variable: (a) years since RCF production hire date: (b) duration of RCF production employment: and (c) cumulative RCF experience. The best evidence to date seems to indicate that pleural plaques are a marker of exposure only.Pleural plaques are not associated with pulmonary impairment. The pathogenesis of pleural plaques remains incompletely understood; however, the mechanism appears to be an inflammatory response caused by inhaled fibres.  Epidemiological studies of RCF production workers have indicated no increased incidence of respiratory disease nor other significant health effects. In earlier studies an apparent statistical "trend" was observed in the exposed population, between RCF exposure duration and some measured lung function. The observations were clinically insignificant. If these observations were made on an individual employee, the results would be interpreted as being within normal (predicted) respiratory range. A more recent longitudinal study of employees with 5 or more pulmonary function tests found that there was no effect on lung function associated with RCF production experience. Initial data (circa 1987) seemed to indicate an interactive effect between smoking and RCF exposure; more recent studies found no interactive effect.  Evidence cited by University of Cincinnati in conducting on-going epidemiological investigations, supports the proposition that:<ol TYPE=1>  · There is no evidence of any fibrotic lung disease (interstitial fibrosis) from evaluation of chest X-rays  · There is no evidence of elevated incidence of lung disease among RCF manufacturing employees.</ol>  In animal studies, long-term, high dose inhalation exposure resulted in the development of respiratory disease in rats and hamsters.  Animal studies with RCFs are confused as a result of insufficient experimental controls. In earlier studies, RCFs together with other man-made mineral fibres were regarded as inert. In the 70's and 80's tumours were produced in animals after intrapleural and intraperitoneal injection but several inhalation studies were inconclusive. Abdominal haemorrhage in hamster abdominal cavities also occurred but this could not be replicated in rat studies. In 1990, inhalation studies known as " the RCC experiments" were conducted with size selected fibres. Fibrosis, lung tumours and mesotheliomas were produced in animals exposed to very high concentrations. It was subsequently discovered that the size selection process lead to a serious contamination of the test samples with non-fibrous particles. The inhaled particles may have decreased the rate of clearance leading to a condition sometimes referred to as pulmonary overload. The significance of the RCC results are still subject to debate. In further tests, uncontaminated fibres have largely proved to be less biologically active. In other inhalation studies, alveolar proteinosis and interstitial fibrosis occurred in some species of rats but in others, further confusing the picture.  Other toxicological studies have been conducted which utilised non-physiological exposure methods such as intrapleural, intraperitoneal and intratracheal implantation or injection. Some of these studies have found that RCF is a potential carcinogen. It is suggested by some that such studies have limited relevance as the bypass many of the biological mechanisms that prevent fibre deposition of facilitate fibre clearance.  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).