The fire at the plant in Shandong province broke out on Sunday evening and was brought under control a few hours later, the report said, adding that 13 people were being treated in hospital.
The company’s managers have been detained by police, Xinhua said, without providing further details.
China, the world’s second-largest economy, has a history of workplace disasters. Workers are often poorly trained or ill-equipped to protect themselves from industrial accidents.
A fire at a poultry slaughterhouse in the northeast province of Jilin in June 2013 killed 120 people. The blaze was blamed on poor management, lack of government oversight and locked or blocked exits. (Reuters)