Twelve people were suffering from fume inhalation and one was injured by burns, they said. They were taken to hospital and their conditions were not life threatening, but five of them were hospitalized.
A production line at the plant caught fire at around 2:20 p.m., local police said. Witnesses reported black smoke coming out of one of the 12 material mixing machines in a smelting process facility at the plant, the police said, adding that another fire broke out in a distributing box in an electric room some 70 meters away from the mixing machines.
Around 20 people were working near the machine when the fire broke out, the police said.
The fire was extinguished around 5 p.m. after gutting around 800 square meters of the facility, according to local fire officials.
Local police and fire department will jointly conduct inspections Saturday morning to find out the cause of the fire, the police said, adding they will investigate the case on suspicion of professional negligence resulting in injury.
The plant, occupying around 378,000 square meters of land, employs around 1,200 workers and produces tires for trucks and buses. The plant halted all of its operations immediately after the fire broke out.
Last September, a fire broke out at another tire plant run by Bridgestone in Kuroiso, Tochigi Prefecture. About 5,000 residents in the area were ordered to evacuate their homes.
Yoshiharu Inoue, chief of the Amagi plant, told a press conference Friday, ''The cause of the fire is not yet known. We offer a sincere apology to the local residents for causing such trouble.''
Meanwhile, Bridgestone President Shigeo Watanabe said, ''We deeply regret that we failed to prevent such a disaster from happening again despite our efforts to rebuild our disaster prevention system after the fire at our Tochigi plant. We are determined to further make every possible effort to devise effective disaster prevention schemes.''
