Ludhiana gas leak leads

Source: By Raakhi Jagga: The Indian Express

11 people died due to a gas leak in the Giaspura area of Ludhiana, Punjab, while four people fell ill and were hospitalised. Any definitive reasons for the leak are not known so far.

Surabhi Malik, the Deputy Commissioner of Ludhiana, said a magisterial inquiry into the incident has been initiated. She said that according to the air quality sensors used by National Disaster Response Force (NDRF) team, high levels of Hydrogen Sulphide gas, a kind of neurotoxin, have been detected and it is being ascertained how this gas might have led to the incident. “It is likely that neurotoxins released might have caused deaths. We are studying the matter,” she said.

What happened in Ludhiana?

The Giaspur area of Ludhiana has several factories and is a thickly-populated area. While the inquiry for the cause of the leak is on, it is suspected that poisonous gas may have emanated from a partially open manhole in the locality and spread to the shops and houses nearby, police said in an FIR. The autopsy reports suggested that the deaths were due to “inhalation poisoning”.

“The cause of death has come out as inhalation poisoning but the type of poison will be clear only after viscera examination. Hydrogen sulphide is so toxic that even one breath of it taken inside can kill a person. Probably some acidic waste was thrown into sewer which reacted with methane, carbon monoxide and other sewerage gases to produce hydrogen sulphide,” said Dr Charan Kamal, forensic expert at Civil Hospital, Ludhiana. The postmortem examination of 10 of the people who died was conducted at this hospital.

“There are several possibilities that may lead to high concentration of Hydrogen Sulphide. It indicates that the sewerage system was not cleaned properly, due to which the gas formation continued. There were no vents within the sewerage system to let the gasses escape,” said a senior Punjab Pollution Control Board official, requesting anonymity.

What are neurotoxins?

Neurotoxins are poisonous substances which can directly affect the nervous system. Neurotoxicity occurs when exposure to natural or man-made toxic substances alters the normal activity of the nervous system. These substances can eventually disrupt or even kill neurons or nerve cells, which are important for transmitting and processing signals in the brain and other parts of the nervous system.

“They directly attack the respiratory tract of the body, thereby overpowering the oxygen concentration of the body and then the nervous system as well,” said Dr Sandeep Goyal, Medical Superintendent at the Dayanand Medical College and Hospital (DMCH) in Ludhiana.

And what are neurotoxic gases?

Methane, hydrogen sulphide, carbon monoxide and carbon dioxide are common neurotoxic gases, said Dr Vitull Kumar Gupta, chairman of The Associations of Physicians of India in Malwa, Punjab. He added, “While methane and carbon monoxide are odourless gases, hydrogen sulphide has a pungent odour and in higher concentration it can be fatal for humans.”

In the present case, the deputy commissioner has indicated that it is likely that a chemical might have reacted with methane gas that is generated during the breakdown of human waste. Samples of sewage were taken from nearby manholes to assess this.

To remove gases such as hydrogen sulphide from wastewater, chemical oxidation is done, where oxidants such as hydrogen peroxide are added to the wastewater.