By Gia Chinh  December 8, 2018 | 01:17 pm GMT+7 Fire trucks are seen at a steel plant in Hai Phong City to help with an explosion on Friday. Photo acquired by VnExpress Police are investigating a steel plant explosion in Hai Phong that killed a worker and hospitalized 11 Friday noon. The blast took place at 12.30 p.m. Plumes of black smoke billowed from the plant run by the Dragon Steel Joint Stock Company in the northern city of Hai Phong, two hours east of Hanoi. The company is said to have leased the plant from the Cuu Long Vinashin Steel Company, a member of the state-owned Vietnam Shipbuilding Industry Group (Vinashin) last June. After several months of repair work, the plant was put into operation Friday morning. The explosion took place just hours after the opening. One unnamed worker died on the spot while 11 others suffered extensive burns and are being treated in local hospitals. The wounded workers are taken to hospital for treatment. Photo by VnExpress/Gia Chinh Investigators have not yet provided any details about the cause of the blaze. Vietnam has seen more than 2,900 fires and 24 explosions in the first nine months of this year, in which 78 people have died. Damage is estimated at VND1.6 trillion ($68.6 million), according to Vietnam Fire and Rescue Police Department.