The death toll in an explosion at a chemical plant in eastern China has risen to 47, with hundreds of others injured.

Thursday’s blast at the Tianjiayi chemical plant in the city of Yancheng is one of China’s worst industrial accidents in years, and has left 90 people in a serious condition in hospital.

Nearly 1,000 area residents have been moved to safety as a precaution against leaks and additional explosions, the city government said.

Aerial photo released by China's Xinhua News Agency, fires burn at the site of a factory explosion in a chemical industrial park in Xiangshui County of Yancheng in eastern China's Jiangsu province
The local government reports the death toll has risen, with dozens seriously injured ((Ji Chunpeng/Xinhua/AP)

Windows in buildings as far as three miles away were blown out by the force of the blast.

The city government statement said 3,500 medical workers at 16 hospitals had been mobilised to treat the injured, dozens of whom remain in critical condition.

The blast created a crater and more than 900 firefighters were deployed to extinguish a fire that burned into the night.

The cause of the explosion remains under investigation.

Chinese president Xi Jinping, on a state visit to Italy, demanded “all-out efforts” to find and rescue victims, the official Xinhua News Agency reported.

Xi Jinping
Chinese leader Xi Jinping demanded ‘all-out efforts’ to find and rescue victims (AP)

He added: “Relief work must be well done to maintain social stability. Meanwhile, environmental monitoring and early warning should be strengthened to prevent environmental pollution as well as secondary disasters.”

China experiences frequent industrial accidents despite orders from the central government to improve safety at factories, power plants and mines.

Among the worst accidents was a massive 2015 explosion at a chemical warehouse in the port city of Tianjin that killed 173 people, most of them firefighters and police officers.

In November, at least 22 people were killed and scores of vehicles destroyed in an explosion outside a chemical plant in the north-eastern city of Zhangjiakou, which will host competitions in the 2022 Winter Olympics.

Thursday’s disaster occurred at a factory run by the Jiangsu Tianjiayi Chemical company. Located among a cluster of chemical factories in Yancheng, it has a dismal safety record.

In February 2018, China’s State Administration for Work Safety cited 13 types of safety hazards at the company, including mishandling of tanks of toxic benzene, the source of Thursday’s explosion.

The site of the blast
The site of the blast (Ji Chunpeng/Xinhua/AP)

Those violations came despite the plant having racked up 1,790,000 RMB (£203,000) in fines since 2016 for violations of environmental regulations, according to judgments issued by local county and city environmental protection bodies.

Those included improperly dealing with hazardous waste and evading air pollution supervision.

A 2017 explosion that killed 10 at a nearby plant prompted China’s national safety regulator, the State Administration of Work Safety, to dispatch inspectors.

They discovered over 200 safety hazards at chemical factories in Yancheng and four nearby cities, including 13 at the Tianjiayi plant.

Safety hazards cited included leaks and drips, employees who did not understand safety procedures, and a lack of emergency shut-off valves on tanks carrying flammable chemicals.

In 2014, the company’s chairman, Zhang Qinyue, and Wu Guozhong, its former supply chief, were arrested on suspicion of dumping and burying hazardous waste by-products near a temple and a village landfill, according to a Jiangsu court criminal judgement.

They were convicted in 2017 and the company was fined 1,000,000 RMB (£113,000).