At least six people were killed in an explosion at a pesticide plant in the eastern Chinese province of Jiangsu on Thursday, state media reported.
The accident occurred in Yancheng and seriously injured 30 people, according to the city’s official account on social media platform Sina Weibo.
Rescue operations were still under way and the cause of the accident is still unknown, the fire department said.
“The cause of the accident is under investigation,” officials said.
A video of the explosion released on social media showed a massive fireball exploding over the factory followed by enormous plums of smoke.
News of the explosion had been viewed by 140 million on Sina Weibo as of Thursday evening and prompted 28,000 comments.
Around the time of the explosion, China’s earthquake administration reported a 2.2-magnitude tremor in Lianyungang, a city near the Yancheng blast.
Footage from state broadcaster CCTV showed windows of nearby houses blown out from the force of the explosion. An aerial view of the blast area showed a large swath of destruction in an industrial park, where multiple fires still raged.
A CCTV reporter on the scene said that toxic fumes were coming from the blast site.
According to official news agency Xinhua, citing local authorities, the explosion occurred following a fire in a fertiliser factory in a chemical industrial park.
Workers near the site of the blast were trapped after shockwaves from the explosion knocked down nearby factory buildings, the report said.
Workers covered in blood were seen running out of the factory, Xinhua added, citing witnesses.
Images broadcast by state media showed an enormous explosion, with flames engulfing the top of the chemical plant.
Other shots showed thick grey smoke billowing skyward from the site of the blast.
Public anger over safety standards has grown in China over industrial accidents ranging from mining disasters to factory fires that have marred three decades of swift economic growth.
In November, a gas leak caused an explosion at a PVC production plant in a northern Chinese city that will host the 2022 Winter Olympics, killing 24 people and injuring 21 others.
A report published by local authorities in February revealed that the Chinese chemical firm responsible for the accident had concealed information and misled investigators.
Last July, a blast at a chemical plant in southwest Sichuan province left 19 dead and 12 injured. The company had undertaken illegal construction that had not passed safety checks, according to local authorities.
And in 2015, giant chemical blasts in a container storage facility killed at least 165 people in the northern port city of Tianjin.
The explosions caused more than one billion dollars in damage and sparked widespread anger at a perceived lack of transparency over the accident’s causes and its environmental effect.