Another 34 people were injured in the explosion Sunday on the outskirts of the city of Panjin in Liaoning province east of the capital Beijing, ABC news reported.
News releases from the local government showed photos of flames and thick black smoke rising from the complex of chemical processing machinery, pipes and storage containers.
Fire crews have brought the blaze under control and the local environmental department was monitoring the impact on air quality in the area, the government of Panshan County in the city's suburbs said in a news release.
The cause of the accident remained under investigation, authorities said. People posting on social media said they felt the shock of the explosion, but the damage did not appear to extend beyond the plant.