4 August 2011
* Full restoration could take 30 years - U.N. report
* Work needs initial $1 billion fund to kick-start
* UN says Shell caused public health issues
* National oil firm, Shell blame sabotage attacks (Adds quotes, details, share price reaction)
By Camillus Eboh and Felix Onuah
ABUJA, Aug 4 (Reuters) - A U.N. report has criticised Shell and the Nigerian government for contributing to 50 years of pollution in a region of the Niger Delta which it says needs the world's largest ever oil clean-up, costing an initial $1 billion and taking up to 30 years.
The United National Environment Programme (UNEP) analysed the damage oil pollution has done in Ogoniland, a region in the oil-rich labyrinthine creeks, swamps and waterways of the Niger Delta, the heartland of Africa's largest oil and gas industry.
Royal Dutch Shell (RDSa.L) and the Nigerian state-oil firm own most of the oil infrastructure in Ogoniland, although the Anglo-Dutch giant was forced out of operating in the region by communities in 1993 who said it caused pollution that destroyed their fishing environment.
Shell stopped pumping oil from Ogoniland after a campaign led by writer and activist Ken Saro-Wiwa, who was later hanged by the Nigerian military government, provoking international outrage.
"The environmental restoration of Ogoniland could prove to be the world's most wide-ranging and long term oil clean-up exercise ever undertaken," a United Nations Environment Programme (UNEP) report released on Thursday said.