An ethics watchdog for the 2012 Games has quit in protest over the link between the Bhopal disaster and Dow Chemical Company's involvement with London's showpiece Olympic Stadium.
An enraged Meredith Alexander is stepping down as a commissioner on the Commission for a Sustainable London 2012 (CSL), whose job is to assure sustainability across the Olympic and Paralympic programme.
Up to 15,000 people died and tens of thousands were maimed when poisonous gas leaked from the Union Carbide factory in Bhopal in central India in 1984. It is one of the world's worst industrial disasters.
Dow bought Union Carbide in 2001 and denies responsibility for Carbide's Bhopal liabilities.
Alexander, who was appointed to CSL in May 2010, said: "I don't want to be party to a defence of Dow Chemicals.
"It is appalling that 27 years on, the site has still not been cleaned up and thousands upon thousands of people are still suffering.
"I believe people should be free to enjoy London 2012 without this toxic legacy on their conscience."
Dow, a global Olympic sponsor since 2010, has stepped in to fund the hi-tech fabric wrap for the 2012 Olympic Stadium which was ditched to save £7 million. Savings of £20 million had been called for.
Hundreds of survivors of Bhopal last month burned effigies of London 2012 chairman Lord Coe and Vijay Kumar Malhotra, the head of India's Olympic organising committee, to protest against the Dow deal.
Dow has always maintained it did not own or operate the Bhopal plant and that legal claims regarding the gas leak were resolved when Union Carbide paid compensation for those killed or injured.
Five Bhopal victims' rights groups have also demanded the scrapping of the sponsorship deal, saying it would give undue publicity to a company that was refusing to clean up the toxic contamination of soil and groundwater.
Amnesty International UK's director Kate Allen said: "Meredith Alexander has made a brave and principled stand.
"She obviously shares our outrage at this association and it is a shame that her concerns, like ours, have fallen on deaf ears.
"It is appalling that Dow has never accepted responsibility for the legacy of the horrific Bhopal tragedy."
She urged them to meet victims.
A London 2012 spokesman said: "Dow was appointed as the supplier of the Olympic stadium wrap in August 2011 following a thorough and competitive procurement process. We assessed all bids on the ability to deliver a sustainable solution and Dow met this criteria by some distance.
"The process has been independently validated by the Commission for a Sustainable London 2012. Dow is a financially sound, well-run international company with over 700 employees across 14 sites in the UK and has been a worldwide sponsor of the Olympic movement since 2010."
Culture Secretary Jeremy Hunt this week stated that there is "absolutely no question there was an appalling human cost", but blame cannot be pinned on Dow.
He told the Culture, Media and Sport Committee that Dow did not own Union Carbide at the time of the Bhopal disaster nor at the time of a final settlement with the Indian government in 1989 that has been upheld three times in the Indian supreme court.
This made him "confident that it was a very reasonable decision" for it to be involved with the stadium, he said.
The firm was also the best sustainability solution for the wrap, he said.
He told the committee this week: "I do not believe that Dow were responsible and I believe that we should support them as a company that wants to do the right thing by supporting a project that will be of huge benefit to the country."
Of the potential damage that the tie-up could cause to London 2012, he said: "Of course if people wish to protest and that attracts publicity that is something that may be with us for a while in the run-up to the Games.
"I think it is also important in these situations to be clear about your principles.
"I think the IOC (International Olympic Committee), Locog (the London 2012 organisers) and the Government have all looked very carefully at this decision. Ethically we think it was the right decision.
"We welcome sponsorship from ethically and morally responsible companies."
Alexander was appointed by London Mayor Boris Johnson to serve on the CSL.
Her CSL profile states: "Meredith Alexander is currently head of trade and corporates at ActionAid. Her career has been focused on communicating sustainability issues to different audiences in the UK and abroad.
"She has helped groups from students to pension fund members better understand how they can contribute to a more sustainable world. She has campaigned on issues including hunger, climate change, supply chains and major infrastructure projects.
"In addition to her work with a number of non-profit organisations, she was a board member for MakePovertyHistory and is chair of the Trade Justice Movement."
Responding to Ms Alexander's resignation, Labour's mayoral candidate Ken Livingstone said: "The controversy over Dow's sponsorship of the Olympic Stadium threatens long-lasting damage to the reputation of the Olympic Games and to the reputation of London.
"Locog and the mayor could resolve this matter by simply admitting they have made a mistake and find another sponsor."