The death toll from a huge explosion at a chemical plant in eastern China surged to 47 on Friday, making it one of the country's worst industrial accidents in recent years.

The blast occurred on shortly before 3pm on Thursday afternoon in Yancheng in Jiangsu province, north of Shanghai.

The explosion was so powerful that it apparently triggered a small earthquake, knocked down several factory buildings and shattered the windows of homes a few kilometres away.

Hundreds of rescuers have been dispatched to the scene of the facility run by Tianjiayi Chemical, local authorities said, and more than 3,000 people have been evacuated from the blast site.

Authorities, who are investigating the cause of the accident, said an unspecified number of people were taken into police custody.The force of the explosion blew out windows and dented metal garage doors of buildings as far as four kilometres from the site.

Nearby residents have started sweeping up glass, and in some cases, seemed to have abandoned their homes entirely. Black smoke could still be seen rising from the chemical plant on Friday morning. The fire was brought under control at around 03:00 local time on Friday.