The firefighter in critical condition is being treated in a hospital nearby.
It took more than five hours to get the blaze under control, though as of press time firefighters were still spraying the embers to ensure the fire is not reignited.
The factory is located on a 20-rai plot of land on Bangna-Trat Road and its paper products served as fuel, causing the blaze to spread rapidly.
The area around the factory has been blocked to outsiders and marked as a hazard zone.
A company representative estimates the damage at more than 100 million baht. The cause of the fire has yet to be determined and investigators are expected to check the premises later today (December 3).