India: North Chennai ammonia leak contained, traced to undersea pipeline, say authorities

An ammonia gas leak that happened at an undersea pipeline in India’s Ennore region, North Chennai, has been contained, said Tamil Nadu government authorities in the early hours of Wednesday (Dec 27).

The leak is said to have occurred around 11.45 pm (local time) Tuesday and it led to the stench of ammonia spreading in the adjoining areas, which includes multiple petrochemical industries and densely populated residential areas.

More than 34 people are said to have been hospitalised after the gas leak occurred around the midnight hour, with the pungent ammonia odour causing eye irritation, a burning sensation in the throat, breathing difficulties, and other issues.

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The leak happened when the liquified form of the gas was being pumped out from a ship at sea to the fertilser manufacturing facility, Coromandel International Ltd. Factory, Ennore.

This facility is involved in the large-scale manufacture of Ammonium Phosphate Potash Sulphate (APPS), with an annual output of almost four lakh tonnes.

The raw material for making ammonia, being a major constituent of APPS, is brought in via ships and transported through a 2.5km long undersea pipeline that leads to the facility.

Estimates say that 3000-8000 tonnes of ammonia is pumped to the factory every month.

It was around 12.45 am on Wednesday that the facility notified the relevant authorities regarding the gas leakage. In the following hours, police and ambulances were mobilised.

At 3.33 am, a top Tamil Nadu Police official Vijaykumar posted on X that the situation had been controlled.

"No need to panic. stabilised. No more gas (ammonia) leak at Ennore. People reassured and are back home. Medical and police teams present."

Speaking to WION, a local resident at Ernavur locality, near Ennore, said that the strong stench of ammonia was observed around midnight hour and led to suspicion of a leak.

He added that his residential area near the coast does not experience such a strong stench, as they are at a considerable distance from the factories in the area.

As on Wednesday morning, he said that the ammonia stench was negligible in his locality when compared to the midnight hour.

Initial reports suggest that this mishap occurred in the run-up to the unloading of ammonia from the ship and not during the actual unloading of the chemical.

In order to transfer ammonia in liquid condition, it is said to be maintained at minus 330 degrees Celsius. At least 36 hours prior to the transfer of ammonia from the ships, pre-cooling of the undersea pipeline is carried out to pump ammonia in liquid form and finally into the storage tank within the factory.

In a statement, Coromandel International said that they noticed the abnormality on Wednesday at 11.30 pm in the ammonia-loading subsea pipeline near shoreside, outside the plant premises.

"Our Standard Operating Procedure activated immediately, and we have isolated the ammonia system facility and brought the situation to normalcy in the shortest time," read the statement.

During the process, a few members of the local community expressed discomfort and were given medical attention immediately. All are safe and normalcy was restored, the firm said.

"We have informed relevant authorities about the incident. Coromandel has always adhered to the highest safety standards and emergency response system" said the firm, in a statement authorised by Amir Alvi, President & Head, Manufacturing (Fertilizer) & Supply Chain, Coromandel International Limited.