In this Feb. 1, 2013 photo provided by China's Xinhua News Agency, rescuers work at the accident locale where an 80 meter (260 foot) section of an expressway bridge collapsed in Mianchi County, Sanmenxia City in central China's Henan Province. An elevated portion of highway in central China collapsed on Friday after a truck loaded with fireworks for Lunar New Year celebrations exploded, killing at least nine people and sending vehicles plummeting 30 meters (about 100 feet) to the ground. (AP Photo/Xinhua, Zhao Peng) NO SALES In this Feb. 1, 2013 photo provided by China's Xinhua News Agency, rescuers work at the accident site where an 80-meter (260 foot) section of an expressway bridge collapsed in Mianchi County, Sanmenxia, central China's Henan Province. (AP Photo/Xinhua, Zhang Xiaoli) NO SALES ALTERNATE CROP OF XIN801 - In this Feb. 1, 2013 photo provided by China's Xinhua News Agency, rescuers work at the accident site where an 80-meter (260 foot) section of an expressway bridge collapsed in Mianchi County, Sanmenxia, central China's Henan Province. BEIJING (AP) - Chinese authorities say a truck that exploded and caused an elevated stretch of highway to collapse, killing 10 people, was loaded with holiday fireworks that were illegally produced and transported. State media say local authorities have shut down the factory where the fireworks were produced and detained four company officials after Friday's blast. It is unclear what set off the fireworks on its shipping route through the central province of Henan. The Ministry of Public Security said Saturday that Hongsheng Fireworks Manufacturing Co. Ltd., based in neighboring Shaanxi province, illegally produced the explosives, improperly packaged them and contracted with a trucking company unlicensed to handle hazardous commodities. Fireworks are a major part of the festivities surrounding the Chinese Lunar New Year, which falls on Feb. 10 this year.