Nigeria's Ogoniland region could take 30 years to recover fully¹ from the damage caused by years of oil spills, a long-awaited UN report says.

一份期待已久的联合国报告称，尼日利亚奥格尼地区常年的漏油问题可能需要花费30年时间才能彻底清理干净。

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The Ogoni people say their land has been devastated by pollution from the oil industry
The study says complete restoration could entail³ the world's "most wide-ranging and long-term oil clean-up".

Communities faced a severe health risk, with some families drinking water with high levels of carcinogens（致癌物） , it said.

Oil giant Shell has accepted liability for two spills and said all oil spills were bad for Nigeria and the company.

"We will continue working with our partners in Nigeria, including the government, to solve these problems and on the next steps to help clean up Ogoniland," Mutiu Sunmonu, managing director of the Shell Petroleum⁴ Development Company of Nigeria (SPDC), said in a statement.

The Bodo fishing community has said it will seek hundreds of millions of dollars in compensation.

Nigeria is one of the world's major oil producers.

'900 times recommended levels'

The UN assessment⁵ of Ogoniland, which lies in the Niger Delta⁶, said 50 years of oil operations in the region had "penetrated⁷ further and deeper than many had supposed".

"In at least 10 Ogoni communities where drinking water is contaminated with high levels of hydrocarbons⁸（碳氢化合物） , public health is seriously threatened," the UN Environmental Programme (Unep) said in a statement.

Some areas which appeared unaffected were actually "severely⁹ contaminated" underground, Unep said.

In one community, the report says, families were drinking from wells which were contaminated with benzene（苯） , a known carcinogen, at 900 times recommended levels.

It said scientists at the site, which lay close to a Nigerian National Petroleum Company pipeline¹⁰, found oil slicks eight centimetres thick floating on the water.

This was reportedly due to an oil spill more than six years ago, it said.

The report, based on examinations of some 200 locations over 14 months, said Shell had created public health and safety issues by failing to apply its own procedures in the control and maintenance of oilfield infrastructure¹¹.

But it also said local people were sabotaging¹²（妨害，破坏） pipelines¹³ in order to steal oil.

The report says that restoring the region could cost $1bn (£613m) and take 25-30 years to complete.

"The environmental restoration of Ogoniland could prove to be the world's most wide-ranging and long term oil clean-up exercise ever undertaken if contaminated drinking water, land, creeks¹⁴ and important ecosystems¹⁵ such as mangroves are to be brought back to full, productive health," Unep said.