Section 1 - CHEMICAL PRODUCT AND COMPANY IDENTIFICATION

PRODUCT NAME

MAGNESIUM HYDROXIDE

NFPA

PRODUCT USE

Intermediate for the manufacture of magnesium metal. Used in sugar refining, paper
manufacture and as an oil additive, therapeutic (laxative, antacid), dentifrices, drying
agent in food etc.

SYNONYMS

Mg(OH)2, "magnesium hydrate", brucite, "milk of magnesia", antacid

Section 2 - HAZARDS IDENTIFICATION

CANADIAN WHMIS SYMBOLS

None

EMERGENCY OVERVIEW

RISK

POTENTIAL HEALTH EFFECTS

ACUTE HEALTH EFFECTS

SWALLOWED

  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.  Magnesium salts are generally absorbed so slowly that oral administration causes few toxic effects, as the dose is readily expelled via the bowel. If evacuation fails, mucosal irritation and absorption may result. This can result in nervous system depression, heart effects, loss of reflexes and death due to paralysis of breathing. These usually do not occur unless the bowel or kidneys are damaged.  

EYE

  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).  

SKIN

  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

  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.  Not normally a hazard due to non-volatile nature of product.  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.  

CHRONIC HEALTH EFFECTS

  Principal routes of exposure are by accidental skin and eye contact andinhalation of generated dusts.  Prolonged use of magnesium hydroxide may result in faecal stones composed  of magnesium hydroxide and carbonate. Magnesium-contaning antacids may  cause renal failure after prolonged use as a result of the precipitation  of magnesium ammonium phosphate in the kidneys. Studies conducted in human  volunteers show that prolonged excessive ingestion of nonadsorbable  antacids containing magnesium-aluminium hydroxide results in depletion of  body phosphorus reserves by rendering dietary phosphorus nonadsorbable  (producing insoluble phosphates in the intestine). This results in  hypophosphataemia, hypophosphaturia, increased absorption of skeletal  calcium and phosphorus and debility with anorexia, weakness, bone pain,  and malaise. Low phosphate diets are also associated with osteomalacia and  proximal myopathies.