Chemicals used in crackers and their harmful effects

•    Lead : Affects the central nervous system in humans. When heated it can emit highly toxic fumes. Young children can suffer mental retardation and semi-permanent brain damage by exposure to lead.

•    Magnesium : Inhalation of magnesium dust and fumes can cause metal fume fever. Particles embedded in the skin produce gaseous blebs and gas gangrene. Dangerous fire hazard in the form of dust or flakes when exposed to flames. Poisoning takes the form of progressive deterioration in the central nervous system.

•    Zinc : Pure zinc powder is non-toxic to humans by inhalation but difficulty arises from oxidation (burning), as it emits zinc fumes. It stimulates the sensation of vomiting.

•    Manganese : Toxicity caused by dust or fumes. The main symptoms of exposure are languor, sleepiness, weakness, emotional disturbances, spastic gait and paralysis.

•    Sodium : When heated in air, it emits toxic fumes of sodium oxide. Can cause dangerous fire hazard when exposed to heat and moisture.

•    Potassium : Dangerous fire hazard and explosion can occur.

•    Copper : Inhalation of copper dust and fume causes irritation in the respiratory tract. Absorption of excess copper results in "Wilson's disease" in which excess copper is deposited in the brain, skin, liver, pancreas and the myocardium (middle muscular layer in the heart).

•    Cadmium : Its absorption can damage the kidneys and can  cause anaemia. Cadmium causes increased blood pressure and also a disease called "Itai-Itai", which makes bones brittle resulting in multiple fractures.

•    Phosphorous in the form of PO4 : Dangerous fire hazard when exposed to heat or chemical reaction. Poison by inhalation, ingestion, skin contact and subcutaneous routes. Ingestion affects the central nervous system. Toxic quantities have an acute effect on the liver and can cause severe eye damage.

•    Sulphur in the form of SO4 : It affects the upper respiratory tract and the bronchi. It may cause edema of the lungs or glottis, and can produce respiratory paralysis. Poison to humans by inhalation. An eye, skin and mucous membrane irritant and corrosive.

•    Nitrate : Highly inflammable and on decomposition they emit highly toxic fumes. The symptoms are dizziness, abdominal cramps, vomiting, bloody diarrhea, weakness, convulsions and collapse.

•    Nitrite : Large amounts taken by mouth may produce nausea, vomiting, cyanosis, collapse and coma. Repeated small doses can cause a fall in blood pressure, rapid pulse, headaches and visual disturbances. When heated, emit highly toxic fumes of NOx.