Olympics: 98% of site now investigated for contamination

Olympic chiefs are hoping there will be no more nasty surprises buried beneath the site now that 98% of the 2.5km2 main park has been investigated for contamination.

All the Big Five venue sites are clean ahead of the start of construction this summer and two-thirds of the entire site has been cleared.

Soil contaminants discovered so far include petrol, oil, tar, arsenic, lead and radium. More than 1.5 million tonnes of contaminated soil has been cleaned for reuse, creating the platform for venues and parklands.

ODA chief executive David Higgins said: "We are cleaning up neglected and polluted land both for the Games and legacy. But we are also using the latest technology to do it in a sustainable way, reusing materials where possible and taking the minimum amount to landfill."