The highly toxic methyl isocyanate gas leaked from the plant, killing 5,479 persons.
Nearly 21 months before the world's worst industrial disaster hit Bhopal, a lawyer had sent a notice to Union Carbide asking it to stop producing toxic gases at its pesticide plant here, citing grave public health risk.
However, the US multinational company summarily rejected his allegations, an act which proved costly as the monumental disaster unfolded on the intervening chilly winter night of December 2 and 3, 1984.
The highly toxic methyl isocyanate gas leaked from the plant, killing 5,479 persons and maiming more than five lakh others.
The lawyer, Shahnawaz Khan, served a legal notice to the Union Carbide India Limited (UCIL) on March 4, 1983, asking it to stop producing toxic gases that risked the lives of 50,000 persons living in the vicinity.
But, instead of putting its house in order by overhauling its safety apparatus, the UCIL on April 29, 1983, in a strongly-worded reply to Mr Khan, dismissed his concerns and charges as "baseless".
In the reply's last paragraph, UCIL's Bhopal unit works manager J Mukund then wrote, "We once again repudiate all the allegations made in your notice of 4th March, 1983, and should you take any legal action against us, the same shall be defended at your risk and cost." The Bhopal-based lawyer is the nephew of freedom fighter Khan Shakir Ali Khan, a four-time MLA from here who was popularly known as "Sher-e-Bhopal".
Shahnawaz Khan told PTI that after getting the reply to his notice, he started collecting documents from police and other sources on the incidents of leak and consequent death to file a case against the UCIL.
"Before I could collect documents, the gas leaked from the Carbide factory," the 73-year-old lawyer said.
Asked about his notice, Mr Khan said he was moved after a worker, Ashraf, of the now-defunct Union Carbide factory in Bhopal died following leak of phosgene gas from the plant on December 25, 1981.
"On January 9 (1982), twenty-five workers were hospitalised following leak at the plant, after which the workers protested," he recalled.
Another toxic gas leak incident occurred in March 1982. After yet another leak on October 5 the same year, hundreds of residents living near the plant were hospitalised, he said.
"Moved by this, I served a legal notice to UCIL on March 4, 1983," Mr Khan said, showing the document and the company's reply.
Mr Khan's notice pointed out that the factory was located within the Bhopal Municipal Corporation limits in the midst of a populated area and more than 50,000 persons are residing in residential colonies adjacent to it.
"Earlier, one person lost his life in your factory. A few days ago, a serious accident took place in your factory," it stated.
With the storage and usage of toxic gases and hazardous and poisonous chemicals, residents in the nearby colonies are living in constant danger. They are living in fear, there is lurking danger of anything untoward happening taking place, the notice said.
The lives of 50,000 persons are in danger. Death looms over them all the time, it stated.
"Therefore, you are hereby, through this notice, directed to stop usage of toxic gases and hazardous and poisonous chemicals in your factory within 15 days from the date of this notice, failing which I shall be constrained to take legal action against your factory in the competent court of law and the consequences thereof Union Carbide shall be fully responsible," it added.
More than a month after Mr Khan served the notice, UCIL's works manager Mukund in his reply said the allegations were baseless and made out of ignorance of the factory operations.
"Our pesticide complex at Bhopal, like any such complex in the world, is equipped with sophisticated devices for handling various types of chemicals in our manufacturing process or any hazardous incident in the course of manufacturing operations and all precautions are taken for safety of persons working in the factory all also those living in the vicinity," the reply read.
"In fact, we have taken appropriate precautions with a view to ensure that no pollution is caused by our pesticide complex and your allegation that the persons living in the various colonies near to the industrial area remain under constant threat and danger, is absolutely baseless," it stated.
The reply further said the company had the requisite permission from the Centre and the state government to operate the plant which is situated in an industrial area.
The US-based Union Carbide Corporation (UCC)-designed Union Carbide India Limited's plant was built in Bhopal in 1969, the lawyer said.
It was a formulation factory for UCC's Sevin brand of pesticides, produced by reacting methyl isocyanate and alpha naphthol, he said.
In 1975, the UCC decided to manufacture ingredients of Sevin at its Bhopal unit. Though the regulations then prohibited polluting activity in the two-km periphery from the railway station, the UCC got necessary clearance, he added.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)