The death toll for an explosion at a chemical plant in eastern China's Jiangsu province rose to 64 as of Saturday morning, with 21 in critical condition and 73 seriously injured, state-run broadcaster CCTV broadcaster reported.

Another 28 are still missing as of Saturday morning, the state-run Xinhua News Service reported.

The blast, which created an enormous fireball and registered as a magnitude 2.2 earthquake, occurred at 2:48 p.m. Thursday in the factory located in an industrial park in Yancheng city in Jiangsu province, about 270 kilometers north of Shanghai.

The cause of the blast is still under investigation. But a worker told Caixin that a fire started in a truck carrying natural gas and expanded to tanks storing benzene, which is highly flammable. Benzene is naturally found in crude oil and petroleum products and is commonly used to make plastics and synthetic fibers.

In the aftermath of the blast, all factories in the park have halted production, Caixin has learned. Many of those factories were damaged by the explosion.

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