Transport authorities in Central China have come under fire for not closing a highway in heavy fog, which led to an accident that killed 13 people.

Visibility on the road was less than 30 meters in Henan province’s Mianchi county on the morning of Feb 1 when a truck loaded with 9 metric tons of fireworks exploded, destroying part of a 30-meter-high bridge, Southern Weekly reported on Thursday.

The traffic bureau is required to close a highway when visibility is less than 50 meters, according to a 1997 regulation issued by the Ministry of Public Security.

However, the highway was not closed until the accident occurred, and there were lots of vehicles on the highway, because it was the travel peak ahead of Spring Festival.

Thirteen people lost their lives in the accident, and 11 others were injured.

An official report on highway maintenance in 2012 found there were many fractures and pits on the surface and the highway had been contracted to unqualified companies, Southern Weekly reported.

The 4,395-km highway is a transport artery that links the coastal city of Lianyungang in eastern Jiangsu province and Horgos, a border port in the northwestern Xinjiang Uygur autonomous region.

The construction quality of the bridge was questioned by the public on the Internet, with many people mocking that the fireworks should be taken to the battlefield for military use.

There has been no official conclusion yet about whether the bridge has quality flaws.

Henan provincial transport authorities did not respond to China Daily on Thursday.

The Sanmenxia city government said on Wednesday that the police have taken 10 suspects in custody on suspicion of illegally producing and transporting explosive materials.

The government said previously that 10 people died in the accident. However, it revised the death toll to 13 on Wednesday after a news report revealed that the truck driver was not in the list of names officials released on Feb 4.

The three added people, including the 34-year-old driver Shi Yanfei, were on the truck carrying the fireworks truck when the accident occurred, the government said, adding that it had taken time to identify the bodies because of the extensive damage caused by the blast.

The fireworks were produced by an unlicensed company in Pucheng county, Shaanxi province, and Shi’s truck was not qualified to transport dangerous products, the government said.

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