The Olympic stadium is sitting under an embarrassing PR cloud after Dow Chemicals were awarded its exclusive marketing rights - a decision which MP Diane Abbott has branded “scandalous” and which could see Indian athletes drop out of the London 2012 Games.

The stadium’s finishing touch, a 20 metre high plastic wrap, is to be provided by the parent company of Union Carbide, which caused one of the world’s industrial disasters.

In 1984 a toxic gas leak from its factory in Bhopal, central India, killed up to 15,000 and injured many more, and even today babies are born with severe disabilities.

Health and human rights groups in Bhopal continue to report high rates of congenital deformities and cancers among families who are forced to use contaminated groundwater sources.

Dow maintains it acquired Union Carbide long after the disaster in 2001, and legal claims were resolved after Union Carbide paid $470m as compensation.

But campaigners say those responsible have still not paid their dues and the matter is subject to ongoing litigation.

Shadow health minister and MP for Hackney North and Stoke Newington Diane Abbott said: “These Olympics were meant to be about a fitter Britain, but they’ve got a series of sponsors associated with ill health and death.

“You’ve got Coca Cola, you’ve got MacDonalds hamburgers which are the key culprit for childhood obesity, and now you’ve got Dow that was once responsible for killing 15,000 people.

“It’s just a grotesque contradiction in terms to talk about the Olympics, but to have so many sponsors who have negative connotations when it actually comes to good health.”

At a press conference last week, MPs, NGOs and campaigners say if the deal is not reversed, Indian athletes could boycott London 2012.

But Olympics bosses defended their links with Dow, which became an Olympic sponsor last year.

A LOCOG spokesman said: “The 1989 Settlement has been challenged twice in the India Supreme Court and both times the settlement was determined to be appropriate.

“This was put out as an open tender in the same way all of our supplier contracts are and Dow put forward the best and most sustainable proposal to supply the wrap.”