Negligence and the violation of established safety procedures were the key causes behind a blast that killed 32 workers and injured 55 others  at the National Thermal Power Corporation’s (NTPC) power plant in the northern Indian state of Uttar Pradesh on November 1.

A magisterial inquiry has been set up to investigate the blast, but initial results point to the possibility of negligence, officials told Asia Times on the condition of anonymity since they are not authorized to speak to the media.

According to senior officials familiar with the probe, the blast was caused by extreme pressure – nearly 50-times higher than normal – due to over-accumulation of ash in the boiler furnace of the 1,550MW coal-fired power plant in the town of Unchahar.

Power station officials were aware of the problem and were working to fix it while the boiler was still running, sources said. “The funnel-shaped bottom of the boiler was being cleared manually by using rods to push out ash clinkers while the boiler was in operation, which is in violation of established safety norms,” government officials told Asia Times.

With the cleaning exercise underway, the furnace pressure increased to the point where hot clinkers of ash fell out, injuring nearby workers. Shortly after, a blast triggered the release of high temperature flue gas and steam, which blew off the boiler lid and caused the many casualties.

NTPC engineers were aware the accumulation of ash in the boiler furnace was choking its ducts. “Because of choked ducts, the temperature of the boiler’s vicinity used to shoot up. After complaints, the generation capacity of the plant was reduced on November 1 from 400MW to 190MW to fix the issue,” sources said.

But the move to reduce generation came too late. The temperature became unusually high and caused the explosion before workers could be evacuated. If plant managers had shut down the unit after spotting the problem, the disaster could have been prevented, the senior officials said.

An explosion at a power plant in the town of Unchahar in the northern Indian state of Uttar Pradesh on Nov. 1 killed at least 32 workers and seriously burned dozens of others. Photo: AFP
An explosion at a power plant in the town of Unchahar in the northern Indian state of Uttar Pradesh on Nov. 1 killed at least 32 workers and seriously burned dozens of others. Photo: AFP

The 500MW unit was commissioned in March and started functioning gradually from August 31. Before the accident, it was operating below its generation capacity, said Ruchi Ratna, an NTPC spokesperson from the Lucknow office.

“Three victims are NTPC employees, of whom one passed away,” she said. Only one of the 32 dead was an employee of NTPC, while the rest were contract laborers. The death toll is likely to go up since some of the injured sustained burns over 90% of their bodies.

According to Ratna, the manual cleaning of the unit was a normal practice. “Using rods to push out ash clinkers to clear the ducts is a normal practice used everywhere. Since the issue was not so severe, we decided to fix it while in plant was in operation. It is also common.”

Meanwhile, the National Human Rights Commission has asked the state government headed by Yogi Adityanath of the Bharatiya Janta Party (BJP) to furnish a detailed report within six weeks on whether negligence led to the explosion.