Three persons were killed and two injured in an explosion in the boiler of the ammonia plant of National Fertilisers Limited (NFL) in Nangal on Saturday.
The explosion took place around 11.40 a.m. due to leakage of hydrogen gas from a pipeline in the shift conversion section of the plant.
"The saturator tower fell and a few lines were detached because of the explosion. Immediate action was taken for safe shut down of the ammonia plant and other plants in the NFL. Total system was isolated and depressurised," said Kuldip Chand, the factory manager.
The extent of the damage and the exact cause of accident are being assessed, he said.
One of the injured has suffered 90 percent burn injuries and is in critical condition at the Dayanand Medical College and Hospital in Ludhiana.
The deceased workers have been identified as senior manager Deepak Chhabra, mechanical engineer Mohinder Anand and contract worker Jarnail Singh.
NFL authorities cordoned off the area after the explosion and nobody was allowed to enter the pant.
Deputy Commissioner Priyank Bharti has ordered a magisterial enquiry to ascertain the cause of the accident.
Police have ruled out sabotage behind the incident and said there was no gas leakage after the explosion.