Chinese President Xi Jinping ordered local governments on Friday to prevent any more industrial disasters after a chemical plant blast left 47 people dead, injured hundreds and flattened an industrial park in the latest such catastrophe to hit the country.
Thursday's explosion in the eastern city of Yancheng, Jiangsu province was one of the worst industrial disasters to hit China, with Xi acknowledging that the country has seen a rash of major accidents in recent years.
Xi - who is on a state visit to Italy - urged "all-out efforts" to rescue those trapped and to identify the cause of the accident "as early as possible", according to the official news agency Xinhua.
The State Council, China's cabinet, has established a team to investigate the explosion, state media said.
The explosion toppled several buildings in the industrial park and caused a huge fire that raged through the night, while rescuers scrambled to find survivors in the wreckage of the plant owned by a company with a chequered past.
The windows of homes a few kilometres away were shattered.
"We knew we'd be blown up one day," said one 60-year-old woman surnamed Xiang who had harboured concerns about safety and pollution for a long time.
More than 600 people have received medical treatment following the blast, according to the city government.
Among them, at least 90 are seriously injured. Hundreds of rescuers have been dispatched to the scene, local authorities said, and some 4 000 people have been evacuated from the blast site.
In a shopping street in Yancheng, a bus was converted into a blood donation centre, with about 20 to 30 people lined up.
Local authorities, who are investigating the cause of the accident, said an unspecified number of people were taken into police custody on Friday.
The facility involved in the explosion belonged to Tianjiayi Chemical, a firm with 195 employees established in 2007 that mainly produces raw chemical materials, including anisole, a highly flammable compound.
Tianjiayi Chemical has a history of violating environmental regulations, according to online records from Yancheng city's environment and ecology bureau.
In 2015 and 2017, the firm was fined for violating rules on solid and water waste management.
In the aftermath of the explosion, several residents told AFP they were concerned about pollution from the industrial accident.
"We don't have drinkable water here," Xiang said. "Why hasn't the government sent us some water?"
According to a report released on Friday by Jiangsu province's ecology and environment department, several rivers near the blast site are contaminated with chemicals, including chloroform and dichloromethane.
The force of the explosion - which was so powerful that it apparently triggered a small earthquake - blew out windows and dented metal garage doors of buildings as far as four kilometres from the site.
Nearby residents - many of them elderly - have started sweeping up glass, and in some cases, seemed to have abandoned their homes entirely.
On the road where Xiang lived, consisting of basic two-storey homes, almost all the windows and some window frames were blown in.
The woman was sitting at home when the explosion occurred and said the force rocked her house and badly damaged her front door.
There was no immediate government help, she said, and residents were clearing the street themselves.
"I have no one to help me here," said a grandmother and single mom surnamed Wang.
"What am I going to do with all the shattered glass on the floor and a broken wall?" the 57-year-old told AFP, tearing up.
The blast toppled buildings, trapping workers. State broadcaster CCTV showed rescuers pulling a survivor from the wreckage.
Workers covered in blood were seen running out of the factory.
An aerial view of the blast area showed a large swath of destruction in the industrial park, where multiple fires had initially raged.
Firefighters extinguished the blaze on Friday after battling raging flames through the night. Three chemical tanks and five other areas had been on fire.
Deadly industrial accidents are common in China, where safety regulations are often poorly enforced.
In November, a gas leak at a plant in the northern Chinese city of Zhangjiakou that will host the 2022 Winter Olympics killed 24 people and injured 21 others.
In 2015, China saw one of its worst industrial accidents when giant chemical blasts in the northern port city of Tianjin killed at least 165 people.