A fire broke out at a Sinopec Shanghai Petrochemical Co Ltd plant in Shanghai early on Saturday, killing one person, the company said.
Roaring fire was seen engulfing part of a sprawling factory, emitting columns of thick black smoke, in a video posted on Twitter by the state-backed Shanghai Daily.
The fire at one of China's biggest refining and petrochemicals plants started around 4 a.m. (2000 GMT on Friday) and had been brought under control by 9 a.m. but "was difficult to handle", state media Xinhua reported, citing fire officials.
It was expected to continue burning for some time.
The driver of a third-party transport vehicle died and a company employee suffered a minor injury, said a Sinopec representative.
He said the fire affected the ethylene glycol facility at the plant in Jinshan, a southwestern suburb of China's financial capital.
State-owned Sinopec said on its official Weibo account it was monitoring volatile organic compounds and impact to rainwater outlets, and no impact on the surrounding water environment had been found.
Sinopec Shanghai has processing capacity for 16 million tons of crude oil a year and 700,000 tons of ethylene, according to its website.
It is building a 3.5 billion yuan ($520 million) carbon fiber project as it seeks to diversify away from refining, and focus on resin and fibers.