YANCHENG, Jiangsu – At least 64 people have been killed and six hundred others injured in a massive blast at a Chinese chemical plant.

According to Xinhua, a total of 640 people were sent to a hospital following Thursday’s explosion at the Chenjiagang Industrial Park in the city of Yancheng, in Jiangsu province on China’s east coast. Many were in critical condition and dozens had severe injuries, the agency reports.

The cause of the explosion was under investigation, but an editorial in the China Daily newspaper said it was likely to be identified as “a serious accident caused by human negligence”.

The company, Tianjiayi Chemical Co – which produces more than 30 organic chemical compounds, has received six government penalties in the past over waste management and air pollution, according to the South China Morning Post.

Many neighbouring factories inside the industrial park caught fire after the explosion.

China’s earthquake administration reported a tremor equivalent to 2.2-magnitude at the time of the blast.

Provincial authorities said firefighters had to be brought in from across the province. The fire was brought under control at around 03:00 local time on Friday, state TV said.

The death toll makes it one of the country’s worst industrial accidents in recent years.

Industrial accidents ranging from factory fires to mining disasters are common in China, often due to poorly enforced safety standards.

The biggest accident in recent years was the August 2015 Tianjin explosion, which killed more than 160 people and injured nearly 1,000.

President Xi Jinping has called for an “all-out effort” to aid the injured and said authorities must learn lessons from the blast prevent future accidents.