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
BEIJING (AP) — A truck that exploded and caused an elevated stretch of highway to collapse in central China, killing 10 people, was loaded with holiday fireworks that were illegally produced and transported, authorities said Saturday.
Local authorities have shut down the company that made the fireworks, Hongsheng Fireworks Manufacturing Co. Ltd., and detained four company officials following Friday's blast, state media reported.
It remained unclear what set off the fireworks as they were shipped eastward on a major highway through Henan province. State-run China Central Television said witnesses believed a collision caused by heavy smog might have triggered the blast, which occurred about 90 kilometers (55 miles) west of the ancient city of Luoyang.
The Ministry of Public Security said Hongsheng, based in the neighboring province of Shaanxi, had illegally produced the explosives, packaged them in disguise and contracted with a trucking company unlicensed to handle hazardous commodities.
It said the factory had failed to check the credentials of the trucking company's personnel.
The state-run China News said the explosives had been declared as general commodities.
Preliminary investigations blamed the explosion for the collapse of the 80-meter (260-foot) stretch of the elevated highway in Mianchi county, sending trucks and sedan cars plummeting 24 meters (79 feet) to the ground, according to a statement by the provincial government of Henan.
Most of those who were killed died from the fall, CCTV said. Eleven people were injured.
Photos by state media and television footage showed hunks of concrete, overturned trucks and crumpled cars in the debris. In one photo, a truck's back wheels were perched at the edge of a shorn-off section of the highway.
"It was horrible. It was horrible," survivor Hou Chunlin murmured from his hospital bed in an interview by CCTV.
Fireworks are a major part of the festivities surrounding the Chinese Lunar New Year, which falls on Feb. 10 this year. To meet the demand, fireworks are made, shipped and stored in large quantities, sometimes in unsafe conditions.
As a result, there are periodic catastrophes. In 2006, on the first day of the Lunar New Year, a storeroom filled with fireworks exploded at a temple fair in Henan, killing 36 people and injuring dozens more. In 2000, an unlicensed fireworks factory in southern China exploded, killing 33 people, including 13 primary and secondary school students working there.