CHENNAI: At least six workers died and several others were seriously injured after an ammonia gas leak at a seafood export unit in Tiruvallur on Sunday (June 21).
According to reports, many were vomiting blood after inhaling the dangerous gas that is used for various purposes such as refrigerant and in the manufacture of plastics, explosives, pesticides, and other chemicals.
Ammonia is a colourless gas with a suffocating odour. It is manufactured by reacting hydrogen with nitrogen. About 80% of the ammonia produced is used in fertilizers. It is also used as a refrigerant gas, and in the manufacture of plastics, explosives, pesticides, and other chemicals, as a corrosion inhibitor, in the purification of water supplies, as a component of household cleaners, in the pulp and paper, metallurgy, rubber, food and beverage, textile and leather industries, and in the manufacture of pharmaceuticals, says the advisory issued by the Agency for Toxic Substances and Disease Registry (ATSDR) of the US.
In most cases, especially those reported in India, ammonia exposure happens in industrial units due to breathing the gas. The severity of symptoms depends on the degree of exposure. The victims will experience burning of the eyes, nose, and throat after breathing even small amounts, while higher doses may lead to coughing or choking.
Exposure to high levels of ammonia can cause death from a swollen throat or from chemical burns to the lungs, adds the ATSDR advisory.
It can also cause serious burns in the cornea of eyes or even blindness.
Those working in industrial units that regularly use the chemical are at higher risk because ammonia causes olfactory fatigue or adaptation – meaning their sense of smell gets adapted to the odour – making it difficult to sense its presence.
The gas is highly irritating to the respiratory tract, and can lead to swelling and narrowing of the throat and bronchi, leading to coughs and accumulation of fluid in the lungs. Upper airway swelling and pulmonary edema may lead to airway obstruction.
It causes rapid onset of a burning sensation in the eyes, nose, and throat.
Exposure can result in corrosive injury to the mucous membranes of the eyes, lungs, and gastrointestinal tract. Even fairly low airborne concentrations (50 ppm) of ammonia produce rapid onset of eye, nose, and throat irritation; coughing; and narrowing of the bronchi. More severe clinical signs include immediate narrowing of the throat and swelling, causing upper airway obstruction and accumulation of fluid in the lungs. This may result in low blood oxygen levels and an altered mental status.