Beinjing, Jan 25 : The building tragedy in China's Jiangxi province that killed 39 people and injured nine others, was caused by illegal use of fire, local authority said on Thursday. The fire in Xinyu City broke out at around 3 p.m. Wednesday after workers doing refurbishment of a cold storage inside the basement used fire illegally, the authority said. According to Xinyu Mayor Xu Hong, heavy smoke soon engulfed the first and second floor, trapping students at training facilities and people in a hotel. The deceased included some students from higher vocational schools, Xinhua news agency reported. A total of 12 people have been taken into custody and are being investigated by the public security authorities. At least 20 fire engines were pressed into service and the inferno was put out at 6:50 p.m. Rescue operation, carried out by 118 members, concluded at 8:50 p.m., said Xinyu fire brigade head Gong Junhui. An inspection to identify hidden fire hazards in all educational institutions, especially boarding schools, has been launched and all after-school training facilities have been suspended, said Xinyu education bureau head Zeng Xianfeng. /IANS