‘Rarest of rare’: Overheating most likely led to deadly explosion at Telangana factory, experts say

The company manufactures microcrystalline cellulose (MCC) from wood pulp. The product is in powder form and is used in pharmaceutical capsules.

In a statement issued on Wednesday, the company denied reports that it was a reactor blast that caused the explosion. “As we wait for the results of the investigation, we would like to clarify that the accident was not caused by a reactor explosion, as mentioned in sections of the media… Since the time of the accident, we have been coordinating emergency response, family support and extending cooperation with the investigation and compliance efforts,” the statement from Sigachi Industries said.

The company also announced compensation of Rs 1 crore to the families of the deceased.

A V Ranganath, commissioner, Hyderabad Disaster Response and Asset Monitoring and Protection Agency (HYDRAA), told The Indian Express that overheating could have caused the blast.

“What could have happened is thermal decomposition of MCC in the spray dryer. That is, MCC powder would have decomposed because of overheating,” he said.

In the dryer, the temperature should be below 200 degrees Celsius, but could have risen above 399 degrees, Ranganath said. “It is at 399 degrees Celsius that the powered MCC starts decomposing. We think the temperatures inside the dryer reached this alarming height and that went unnoticed,” he said.

The temperatures could have been controlled had the interlocking system, which cuts off heat at a predetermined level or sets off an alarm, worked. “In this case, the rise in temperature, which reflects on a monitor in the factory, could have gone unnoticed or unchecked,” Ranganath said.

He said this sort of overheating is a “rarest of rare case”.

“There is no history, so to speak, of such massive overheating to have happened elsewhere. This was an unfortunate incident and a rarest of rare case,” he said.

The extent of the explosion was such that whole portions of the factory collapsed. A case has been registered against the company management under sections for attempt to culpable homicide not amounting to murder, and voluntarily causing grievous hurt. No arrests have been recorded in the case so far.

The company has been functioning out of its facility in Pashamylaram for 35 years, the HYDRAA commissioner said.

Another expert from the department of factories, who spoke on the condition of anonymity, said, “The company did have a mechanism to cut off heat because the product would have been compromised had there been no such mechanism. The cut-off mechanism is not just for safety but for ensuring the quality of the product.”

The number of casualties was high because workers from two shifts were present at the factory on the day of the incident, Ranganath said. There were workers from both the general shift and night shift at the factory when the explosion took place. “They were having a meeting when the explosion happened. This resulted in a high number of casualties and injuries,” he said.

Meanwhile, the search operation is still underway for those still missing following the blast. Officials have collected DNA samples of several relatives to find matches.

As per official sources, out of the 38 dead, 18 bodies have been handed over to family members. “A total of blood samples from 25 people are being processed at the lab. Five samples have already been matched,” a district administrative officer said.

The Telangana government has formed an expert committee comprising officials from the Indian Institute of Chemical Technology (IICT) to probe the accident.