A record appeared on the web from a surveillance camera that captured a mass accident that occurred last Monday, February 17, on a expressway in South Korea.It all started with the fact that the trailer carrying armored vehicles stopped in the tunnel due to ice. Just a few seconds later, an accident occurred near him and a cork began to accumulate.Gradually, more and more cars drove up to the site of the collision, crashing into the standing vehicles. Some drivers managed to navigate the situation and continued to move after the accident, having managed to leave a dangerous place, but there were a minority of them.The situation deteriorated sharply after several trucks flew into the cluster of cars, including a tank truck carrying about 18 tons of nitric acid, the toxic fumes of which filled the space of the underground section of the route.After that, a powerful fire broke out in the tunnel - the arrived firemen did not immediately manage to cope with the fire.According to local media , three dozen cars became participants in the collision, four people died, another 43 received injuries of varying severity.Currently, law enforcement officers have failed to identify all the victims of the incident, as the bodies were badly damaged by the fire. Police turned to specialists from the National Institute for Scientific Research with a request to conduct a genetic examination.In addition, law enforcement agencies paid close attention to the work of the road services responsible for servicing the section of the highway where the accident occurred. In particular, the investigation is interested in anti-icing measures that were held that day.