Thousands of litres of furnace oil spilled into a canal after three tank wagons of a train carrying the thick liquid derailed in Hathazari upazila yesterday.
The waterbody flows into the Halda river, a unique natural breeding ground for carp.
The derailment occurred in Moddom Deyan Nagar around 2:40pm when the seven-wagon train was taking the oil to a 100MW power plant in the area.
It was coming from an oil depot in Patenga and each of the wagons had around 24,500 litres of furnace oil, said railway sources.
The local administration claimed they acted promptly and was able to prevent oil slicks from spreading to the Halda.
But the wagons could not be retrieved till last night, meaning there are chances that the river could be affected.
The accident spot is nearly three kilometres away from the Halda.
Visiting the area yesterday afternoon, this correspondent saw oil oozing from the wagons in the Morachora Canal. Oil slicks appeared at least one and half kilometres away.
Near Moddom Deyan Nagar, workers were seen throwing sand bags to build a makeshift dam.
Hafizur Rahman, a witness, said he heard a loud bang and saw wagons coming off the tracks. “I saw the train, it looked like its speed was higher than in other days,” he said.
Several railway sources echoed his views, but added a probe to this end was underway.
The sources said trains carrying furnace oil are advised to ply at maximum 20 kilometres per hour, but it appeared that the train was running over 30kmph yesterday.
Abu Taher, another local, said the local administration came up with a quick response, which apparently helped prevent oil spills mixing with the Halda water.
Contacted, Hathazari Upazila Nirbahi Officer Ruhul Amin said they constructed a total of 10 small makeshift dams with sand bags within one and a half kilometres of the spot, put up oil-booms over them and soaked up spilled oil using foams.
Banana trees were also thrown into the water.
“Hundreds of workers were immediately engaged so that the oil can’t reach the Halda. We were able to contain the [oil] spill,” he said, adding that they hoped to retrieve the wagons by this morning.
Prof Manzoorul Kibria, an expert on the Halda, said the oil did not spill into the river yesterday, thanks to a quick response from the administration.
“Halda and its diversity would have received a heavy blow had the oil flowed into the river,” he said, stressing the need for recovering the tank wagons immediately.
Manzoorul also said the railway tracks were too weak to sustain the weight of heavy tank wagons.
He then claimed that the railways did not take any lesson from a similar incident in Chattogram in 2015.
On June 19 that year, another train veered off its tracks and three oil wagons went into a canal in Boalkhali upazila’s Khitabchar area. A few days later, a huge quantity of furnace oil spilled into the Halda and the Karnaphuli rivers.
Contacted, Md Borhan Uddin, divisional railway manager (Chattogram Division), said a three- member probe body was formed to investigate yesterday’s incident.
The committee members include Md Mizanur Rahman, chief mechanical engineer; Abdul Jalil, chief engineer; and Sujit Kanti Das, chief operating superintendent; of the railway zone. They visited the spot yesterday.
“Another five-member probe body was formed at the divisional level. The committee would submit its report within a week,” he said.
He also said the investigation would also look into the speed of the train.