Seven people, including six toll plaza employees and the driver of an LPG tanker, were injured after the vehicle crashed into a toll booth and caught fire in Uttar Pradesh's Kaushambi on Friday.
According to the police, the tanker went out of control in the Kokhraj police station area, struck a road divider and then rammed into a toll booth.
The impact caused gas to leak from the tanker, which subsequently ignited, triggering a massive fire that engulfed the area.
The flames were so intense that they were visible from nearly two kilometres away.
Several fire tenders rushed to the spot and brought the blaze under control.
Superintendent of Police Satyanarayan Prajapat said the tanker driver fled after the accident.
He said all fire brigade units in the district, along with civil police personnel, were deployed at the site.
Fire personnel continue to monitor the area even after the fire was put out, he added.
Four toll plaza employees -- Alok Singh, Hiramani, Atul Mishra and Krishna Pal Maurya -- along with the driver were admitted to the district hospital before being referred to SRN Hospital in Prayagraj after their conditions were found to be serious.
Two other injured toll workers were admitted to the Muratganj Community Health Centre and are stated to be out of danger, the police said.
Officials said the district supply inspector and a technical team have been informed about the accident.
The technical team will investigate all aspects of the accident to ascertain the cause of the fire.
(With inputs from PTI)