The leak has been fully plugged and there is no cause for concern, the Tamil Nadu Pollution Control Board (TNPCB) said, following protests by people who sought closure of the plant.
"Within 20 minutes, the gas leak was plugged by specialists," an official release here said, adding that "the TNPCB has confirmed that there is no ammonia leak now." Following the gas leak, the TNPCB ordered immediate suspension of operation of the Ammonia offshore pipeline activity for precooling and transfer.
The unit shall resume activity only after ensuring the safety of the pipelines and after obtaining a No Objection Certificate from the Directorate of Industrial Safety and Health, the TNPCB said in a notice to the fertiliser manufacturing unit.
Also, other directions to the unit includes approval from Indian Register of Shipping and the TN Maritime Board.
The government has constituted a technical committee of experts to look into the matter and submit its immediate field assessment report within 24 hours and a full report within three days.
The gas leak took place around 11.45 pm on December 26 and some fishermen and local residents who happened to be on the beachfront at midnight noticed unusual sounds and water gushing from some spots above the subsea pipeline.
"We noticed abnormality on December 26 at 11:30 p.m. local time (1800 GMT) in the ammonia unloading subsea pipeline near shoreside, outside the plant premises," Coromandel said in an exchange filing earlier in the day.
Forty-four people were rushed to Akash Hospital in Chennai, two hospital officials told Reuters, on condition of anonymity, as they were not authorised to talk to the media.
Six others were admitted to Stanley Medical College and Hospital near Ennore, local media reported earlier, quoting Tamil Nadu Health Minister Ma. Subramanian.
The Tamil Nadu government said in a statement that the leak took place when Coromandel's fertiliser manufacturing unit was preparing to receive an ammonia shipment through its 2.5 kilometre-long (1.5 mile) undersea pipeline.
"The unit observed pressure drop in the pipeline at around 11.45 pm and simultaneously observed pungent odour around the storage terminal and near the material gate," the statement read.
"They will identify the exact location and the extent of pipeline damage within a day and will rectify the same before commencing the ammonia transfer."
"All are safe and normalcy is restored. We have informed relevant authorities about the incident," Coromandel added.
Coromandel's shares dropped as much as 3.7% on Wednesday, before closing 1.6% lower.
The incident comes weeks after an oil spill in the same area from a refinery belonging to Indian Oil-owned (IOC.NS) Chennai Petroleum Corp (CHPC.NS) during Cyclone Michaung.
