The injured were being treated at an area hospital, the provincial bureau of workplace safety said, without specifying the extent of their injuries.
Some 430 firefighters were battling to douse the fire in Zhangzhou city, state-run Xinhua news agency reported.
This is the second accident in nearly two years at the same facility that produces paraxylene (PX), an industrial chemical used for making fiber and plastics.
Windows were broken at a gas station anout a kilometre away from the blast site.
PX plants are highly controversial projects in China. All the proposed plants have met strong public opposition in recent years.