The ruling Chinese Communist Party on Monday blamed "human error" for a fatal oil pipeline explosion that has killed at least 55 people and injured 136 in the eastern province of Shandong.
"This is a very serious accident caused by human error," the state news agency Xinhua quoted Yang Dongliang, director of the State Administration of Work Safety, as saying amid the launch of a probe into the accident, which rocked an industrial district in the port city of Qingdao on Friday.
Yang said an initial investigation had uncovered poor design of the pipeline and local drainage networks, negligence on the part of safety officials and bad maintenance practices.
He also blamed local officials' failure to seal off the affected area and evacuate residents after the leak was detected, seven hours before the blast, Xinhua said.
Authorities in Qingdao's Huangdao district had imposed a security lockdown by Monday around the site of the blast, which came after a leak in a pipeline owned by major state-owned oil company Sinopec, residents said.
Photos published by state media showed large sections of road torn apart into sections, surrounded by overturned vehicles and billowing smoke.
Local residents said they had received scant information about the accident from local authorities, however.
"They should give local residents an explanation," said a resident of Qingdao's Huangdao district, who gave only his surname Zhao.
"They knew before the explosion that there was an oil leak, so why didn't they evacuate everyone?"
Zhao said the site of the leak had only recently been safety checked by Sinopec staff.
"How do you explain the fact that the section that was checked and found to be sound was the section that exploded?" he said. "It's quite possible that they just went through the motions [of checking]."
Friday's blast came after the pipeline began to leak, resulting in the worst oil spillage into Chinese waters in recent years, Xinhua cited local government sources as saying.
The leak spread across more than 3,000 square meters of sea around the Jiaozhou Bay area of the Yellow Sea, the Qingdao municipal government said in a post to its official account on the Twitter-like service Sina Weibo.
Zhao said police had since sealed off the area near the pipeline, which was still at risk.
"There are still hidden dangers in the pipeline, and if they're not dealt with properly, there could be a second explosion," he said. "They aren't even letting pedestrians go past it."
He said local people were still very worried about their safety.
"The pipeline is too close to the residential area," Zhao said. "It's right in the center of a major avenue [underground], and the residential area is just to one side of that."
A second Huangdao resident, who gave only his surname Song, said Chinese president Xi Jinping had arrived in the city on Sunday.
"He went to the hospital to take a look, and to comfort the relatives of those who died or were injured," Song said.
"We heard the explosion; it was very powerful," he added.
"All the windows in Huangdao were shattered. It was lucky that the explosion happened on a Friday; if it had been a Saturday, I think a lot more people would have died."
Pledge to investigate
A third resident surnamed Gao said local people still remembered a blast that shook Huangdao in 1989, when a series of oil tanks blew up after a lightning strike.
"They should never have built that refinery," Gao said. "The house prices in Huangdao have all fallen, and no one wants to live there."
"The local people never agreed to it," he said. "The Qingdao government is very corrupt, and local people have become numb to it."
Sinopec said it was "deeply sorry" for the accident, and said it was launching a probe into the cause of the blast.
"We ... express our sincere condolences to the victims and their families," the state-owned company said in a statement on its website.
"We will investigate the cause of the accident in a responsible manner, and keep the public informed of our progress."
According to China's State Administration of Work Safety, more than 27,700 people were killed or went missing at workplaces in the first half of this year alone.
Last June, two people died in a blaze at an oil complex owned by PetroChina, which the company described as a "serious accident" at the time.
Qingdao, a major oil port, is home to a mega-capacity refinery and petrochemical complex owned by Sinopec.
The city's environmental protection bureau said authorities are currently organizing a major clean-up of the oil spill. The leak wasn’t caused by a terrorist attack, the bureau said.
Reported by Qiao Long for RFA's Mandarin Service. Translated and written in English by Luisetta Mudie.