Kanpur, Aug. 21 -- Three persons were charred to death and another sustained injuries after a chemical-laden truck and a dumper collided head-on on the Hardoi-Unnao Road in Unnao district early on Wednesday. The impact of the collision, which occurred around 3 am, triggered a massive explosion, and within minutes, both vehicles were engulfed in flames. Eyewitnesses said the drivers of the two vehicles and a cleaner were trapped in their cabins as the blaze spread rapidly. Despite desperate attempts by locals to rescue them, the men remained stuck for nearly half an hour. The deceased were identified as Mahipal (30), the DCM truck driver from Muzaffarnagar; Pawan Yadav (24), the dumper driver; and Sumit (24), one of the cleaners. Sonu, another cleaner, managed to escape by jumping out of the cabin through a window. He sustained injuries to his leg and was admitted to the district hospital. While the truck was reportedly carrying chemical supplies from Muzaffarnagar to Kanpur, the dumper was ferrying red sand to Safipur. Residents recounted that the explosion was so loud it was heard nearly half a kilometre away, while flames shot up to 15 feet high. The accident led to a traffic jam with vehicles stranded on both sides of the road. Police and fire brigade personnel battled the blaze for nearly three hours before bringing it under control. Traffic movement was restored by around 6 am. "The men trapped inside were crying for help, but the fire was too intense. Within moments, everything turned to ashes," recalled eyewitness Rahul Bhadauria. Another local, Mahendra Pal, said the tragedy could have been far worse had it not been for the low traffic volume at that hour. SP Unnao Deepak Bhuker said the charred bodies were retrieved after breaking open the cabin doors and sent for a post-mortem examination. Both vehicles had since been removed from the site, he added....