A PetroChina unit in Shaanxi has been shut down after oil from a ruptured pipeline contaminated a source of drinking water for 200,000 residents of the city of Yanan .
The 100-kilometre pipeline, which runs upstream of the Wangyao Reservoir in Zhidan county, was damaged during a landslide sometime before Monday, when the leak was discovered, the local government said.
It is unknown how much oil reached the reservoir, which has a capacity of 200 cubic metres and serves some 200,000 residents. An estimated 13 tonnes of oil was lost during a similar leak from the same pipeline last week.
Nearly 2,000 workers, including 300 from PetroChina and 1,500 from the local government office, have been sent to repair the pipeline and contain the spill. It took 11 hours to repair last week's leak.
The city government shut PetroChina's pipelines, wells and storage facilities near the reservoir to protect the water supply, said China Business News. It has begun drawing its drinking water from another reservoir.
PetroChina's Beijing-based spokesman Mao Zefeng , said it was trying to contact the local unit for more details.
The landslide that ruptured the pipeline was one among many caused by days of torrential rainfall during the past two weeks. Zhidan county received more than 20cm of rainfall - or 4½ times the rainfall in the same period last year.
Yanan - a major oil-and-gas production site because of PetroChina's Changqing oilfield - had seen rainfall at once-in-a-century levels, said ya123.com Yanan's official news website. The city has a population of more than two million.
Flooding and landslides have been blamed for killing at least 26 people, injuring 118 and causing direct economic losses of 1.6 billion yuan (HK$2 billion), the city government said. More than 32,500 residents have been relocated, and the Shaanxi provincial government has set aside 4 million yuan for any contingencies.
It is not the first time supplies from Wangyao Reservoir had to be suspended because of an oil spill. More than 20 tonnes of oil leaked in a similar incident caused by heavy rain in 2007.
In November 2011, the central government issued a disciplinary warning to China National Petroleum Corporation, the parent of PetroChina. The warning was over an accident in 2010, when an explosion caused an oil spill that polluted an area of more than 183 square kilometres off the coast.
Additional reporting by Bloomberg