Ludhiana: Ineffective manhole cleanup, chemicals disposed in sewers emerge as theories for Giaspura tragedy

Steps to be taken in the event of an industrial accident or to gauge its environmental impact lacking, say experts

By Rohini Krishnamurthy
Published: Monday 01 May 2023

Police stand guard in Giaspura, Ludhiana after the gas leakage on April 30. Photo: @PunjabGovtIndia / TwitterPolice stand guard in Giaspura, Ludhiana after the gas leakage on April 30. Photo: @PunjabGovtIndia / Twitter

A gas leak in Ludhiana killed 11 people while four others were admitted to hospital in the wee hours of April 30, 2023. The exact cause is still being investigated, but two theories have emerged.

Authorities have detected high levels of hydrogen sulphide, a highly toxic gas, in Ludhiana’s Giaspura locality. “It has been 24 hours since the incident, and the investigation is still going on,” Nivit Yadav, programme director of the industrial pollution unit at Delhi-based Centre for Science and Environment (CSE), told Down To Earth (DTE).

Hydrogen sulpide at low levels triggers irritation of the eyes, nose and throat. Moderate levels lead to headache, dizziness, nausea, vomiting, coughing and difficulty breathing. The gas gives an unpleasant smell at concentrations above 0.5 parts per million (ppm), according to a 2014 paper.

Higher levels can cause shock, convulsions, coma and even death, according to Centres for Disease Control and Prevention. Hydrogen sulphide concentration above 50 ppm is life-threatening, and above 700 ppm, it can be fatal.

Hydrogen sulphide occurs naturally in sewers. It tends to build up in low-lying and enclosed spaces, such as manholes and sewers.

Yadav has heard from sources that the manhole was cleaned recently. “But we cannot be certain how effective the cleaning was,” he added. Leakage may have occurred if the cleaning was not done correctly.

Alternatively, some chemicals may have been disposed of in the sewer. This, in turn, may have produced more hydrogen sulphide.

Also, according to sources, there was a broken manhole as well in the locality. “Most of the victims belonged to two families living near it,” Yadav noted.

Ludhiana, according to the expert, has a large number of garment industries. “It has to be seen whether any chemical was released. We will know more in the next 1-2 days,” he added.

He highlighted that if it was an industrial accident, a proper investigation needs to be done.

Past disasters

India has had its share of industrial accidents. From 2010 to 2020, 560 industrial accidents have been reported to have caused environmental damage, mainly air and water pollution, according to a 2023 paper published in Safety Science.

During this period, about 2,500 lives have been lost, and another 8,500 people injured, researchers wrote in their paper.

One of the world’s worst gas leaks occurred at Union Carbide Limited in Bhopal in 1984.

A pesticide plant in Bhopal released more than tonnes of methyl isocyanate gas, killing at least 3,800 people and causing significant morbidity and premature death for thousands more, a 2005 study noted.

More recently, in May 2020, styrene — a chemical used to make latex, synthetic rubber and polystyrene resins — leaked into the environment from a Visakhapatnam facility that produces expandable plastics. The levels were 500 times higher than the prescribed limit. The death toll was 11.

The same year in June, an explosion occurred at a pesticide factory in Gujarat’s Dahej town in Bharuch district. The disaster killed eight people and injured more than 50 workers.

In May and July, boilers exploded at the thermal power station of Neyveli Lignite Corporation Ltd in Tamil Nadu’s Cuddalore, killing at least six people and injuring 17 others.

“There are no stock-taking attempts at the national or sub-national level to evaluate the environmental damage due to the industrial accident,” the Safety Science paper read.

Environmental impacts of industrial disasters like contaminated water, contaminated soil, air pollution, or biodiversity loss can directly or indirectly impact human well-being, the paper warned.

It is also essential to take timely steps in the event of a leakage, G Srimannarayana, a retired professor at the Department of Chemistry, Osmania University, and Hyderabad, told DTE.

“Electronic sensors must be installed to alert people in control rooms. Additives such as ethyl mercaptan, which has a pungent smell, could be added to odourless, toxic gases. Ethyl mercaptan is added to LPG to warn people of leaks,” he says, adding that these steps are not being taken.

The Safety Science paper also urges policymakers to ensure that industries spell out appropriate safety measures, engage in community awareness of the risks involved in the organisations’ operations and take responsibility for human and environmental damage in the event of an accident.

The paper also called for efforts to maintain and update a national-level database on the environmental damage from industrial accidents.

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