The explosion occurred on Tuesday at a factory in central China's Henan province, the country's media said, citing local authorities.
Footage allegedly taken at the scene and circulating online shows the moment the sky turns red from the flames and a massive mushroom cloud rising after the blast occurred.
Another video shows the explosion from several angles.
According to social media reports, the incident occurred at an electrolytic aluminium smelter, and between 40,000 and 50,000 tonnes of capacity may be affected.