Firefighters work at the blast site in Panshan County, Liaoning Province, northeast China, January 15
More than 30 other people were injured in the explosion Sunday on the outskirts of the city of Panjin in Liaoning province east of the capital, Beijing.
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 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 statement.
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.
China, with the world's second-largest economy, suffers deadly industrial accidents on a regular basis.
The central government has pledged stronger safety measures ever since an explosion in 2015 at a chemical warehouse in the northern port city of Tianjin killed 173 people, most of them firefighters and police officers.
In that case, a number of local officials were accused of taking bribes to ignore safety violatio