10 years since Sterlite gas leak: Another reason why smelter was shut down

This anniversary is an occasion to remember that Sterlite's closure is not on account of a conspiracy but due to orders issued by a statutory body and a duly elected government and upheld by a court.

Today – March 23, 2023 – is the 10th anniversary of the Sterlite gas leak disaster in Thoothukudi. Many outside Thoothukudi may not remember the disastrous leak, or associate Sterlite's closure with the leak. But anniversaries are a good time for stock-taking and for remembering – Remembering, in the case of Sterlite, that the company is currently challenging two closure orders, not just one, in the Supreme Court.

The first is the set of 2018 orders of Tamil Nadu Pollution Control Board (TNPCB) and the Government of Tamil Nadu downing the controversial smelter's shutters, and the second, the March 2013 order of the TNPCB closing the factory in the wake of the gas leak. Both sets of orders were upheld by the Madras High Court in August 2020 when it found the directions to close down the smelter on two different occasions necessary and consistent with law.

This anniversary is a time to remember that Sterlite's closure is not on account of a conspiracy but due to orders issued by a statutory body and a duly elected government, orders that were subsequently upheld by a Division Bench of the Madras High Court.

On that fateful day in 2013, when morning walkers were still doing their rounds, an invisible gas descended upon the city of Thoothukudi. Thousands experienced suffocation and burning sensation in their throats and eyes; hundreds had to be rushed to the hospital and at least one pregnant woman reportedly miscarried. The gas leak brought back memories of an earlier incident in 1997 when 20 women workers from a dry flower factory on Sterlite's fenceline had to be hospitalised after inhaling toxic, corrosive fumes. The district collector shut Sterlite down; but the company managed to get off the hook by deflecting blame and taking advantage of "inconclusive" evidence. This time too, it attempted to explain away the leak and exculpate itself.

But this gas leak was different. For one, it was not an isolated incident inside a factory. An entire town was affected. And then, acting on directions from the TNPCB, the company had installed online sulphur dioxide (SO2) emissions monitors atop the smokestacks of the two Sulphuric Acid Plants (SAP), and ambient air quality monitors in a few locations around the factory. The monitors would measure SO2 in real time and instantaneously convey the readings to the TNPCB's CARE Air Centre in Chennai.

After having been shut down for maintenance from March 21, on March 23, at around 12.50 am Sterlite began start-up operations, and started the SAPs. In a copper smelter, SAPs are the main source of SO2, a corrosive and highly toxic gas. Between 2 and 2.45 am, and again from 9.15 am to 11.15 am., SO2 readings in the displays at CARE Air Centre went off the charts, exceeding 1123.6 ppm -- the highest end of the range of the analyser.

Sterlite's central defence lay in questioning the veracity of the reported incident by feigning ignorance about it, and with claims that the high SO2 values were of calibration gas not actual emissions, and that they had "inadvertently" left the software in "maintenance" mode even after calibration was concluded at 2.45 am.

After considering the arguments and counterarguments, the Madras High Court concluded that Sterlite's story did not add up.

Calling out the company for downplaying the leak, the Court observed that: "In the reply to the show cause notice, the petitioner states that they "understand" that certain complaints were received from the public regarding eye irritation and throat suffocation. This reply is dated 27.03.2013, and much prior to that, the statement given by the District Collector was reported in the Tamil dailies. . .Therefore to feign ignorance of the incident is unbecoming of a corporate of this magnitude, such as the petitioner."

Elsewhere, the court said "The incident cannot be disbelieved and it is held that there was admittedly a spike in the gas which has caused hardship to the public, which resulted in a panic situation in the area, which has compelled the Revenue Administration to issue a press release."

Dismissing the petitioner company's attempts to downplay the incident, the High Court observed: "The petitioner cannot attribute any motive to the local public because on one hand, they say several of the local public want their industry to continue operations. That apart, the petitioner cannot attribute motives to the general public spread over the length and breadth of Thoothukudi. Therefore, the petitioner cannot wriggle out to state that they have nothing to do with the said incident."

Commenting on Sterlite's defence of the high values by claiming that it was a calibration exercise and "inadvertent" error, the court said: "The candid admission of [Sterlite] that the software was in a maintenance mode inadvertently is hard to believe especially when, the petitioner has taken a stand that they have adopted a state of art technology and even their trucks, which transport the raw material are GPS monitored. Therefore, the "story" which they seek to tell about the maintenance mode of the software is unbelievable and to be disbelieved and there is something more than what meets the eye. . ."

To decide on Sterlite's culpability, the court relied on a guided interpretation of facts which were presented to them by TNPCB and citizen respondents.

At around 2.50 am, the Ambient Air Quality monitor recorded a steep increase in SO2 levels – from 10 ug/Nm3 to about 40 ug/Nm3 by 3.50 am, and declining thereafter until 5.50 am, at which point the monitor registered another surge. This time, it touched nearly 60 ug/Nm3. Data from this monitor mysteriously vanishes after 10.05 am.

"This is curious and raises questions as to why the monitor stopped working precisely around the time of the second instance (9.15 am to 11.15 am) that the CARE Air Centre recorded SO2 levels in excess of 1123.6 ppm," wrote Prof T Swaminathan, a retired chemical engineer from IIT-Madras, in an opinion that was relied upon by the court. Swaminathan is familiar with the company. He was a member of the Inspection Committee constituted by the Supreme Court when the company appealed a High Court order shutting them down in 2010.

The retired professor observed that complaints from Thoothukudi residents began flowing in from around 6 am reporting symptoms like coughing, burning sensation in eyes, nose and throat, difficulty breathing and a suffocating feeling.

These symptoms are consistent with SO2 poisoning. Copper smelters are a known source of SO2. According to the US Government's Agency for Toxic Substances and Disease Registry, SO2 severely irritates the eyes, mucous membranes, skin and respiratory tract. Exposure to even low concentrations can aggravate chronic respiratory diseases like asthma.

At the time of the leak, the wind was blowing from West Northwest to East Southeast at a speed of 1.22 km/hour, the court noted. That placed the densely populated portions of Thoothukudi exactly downwind of the factory. The edge of town is around 4km East Southeast from Sterlite and the coast in that direction is 9 km away.

"At [1.22 km/hour], the pollutants can begin affecting the edge of town within 3.5 hours, with more intense effects being experienced in places further downwind where the plume settles to the ground. This corresponds with the sequence of events and the timing of onset of symptoms reported by residents of Thoothukudi," Swaminathan wrote.

On 23 March, given the meteorological conditions, Sterlite was the sole large emitter of SO2 upwind of Thoothukudi. The thermal power plant and SPIC-TAC were in a crosswind direction from town, ruling out their hands in the day's poisoning.

Swaminathan is categorical in his conclusion: ". . .just going by the available readings, the chronology of events – namely, the timing of the disputed emissions from Sterlite, the meteorological conditions, the readings in SIIL Township's online AAQ monitor and the onset of symptoms, I am of the opinion that evidences strongly point towards Sterlite as the source of the emissions responsible for the acute exposure effects on 23.03.2013." AAQ here refers to Air Ambient Quality.

Giving due credence to the technical opinion offered by Prof Swaminathan, the High Court found "that the stand taken by the TNPCB to be just and proper and the professional opinion rendered by the expert also aids and strengthens the decision taken by TNPCB leading to closure of the petitioner industry."

Rightfully, today ought to have been the 10th year anniversary of Vedanta's closure. Thirteen people would not have fallen prey to police bullets.

(Nityanand is a social activist and writer and worked in solidarity with the Thoothukudi people's struggle to hold Vedanta accountable for pollution)