At least five people have died and 10 others have been injured after the reactor in a chemical factory in Telangana's Sangareddy district exploded.
Several others are still trapped, officials told NDTV, meaning the number of dead could increase, perhaps drastically. Local reports suggest 50 men were in the building at the time of the explosion.
Disturbing visuals from the scene showed the magnitude of the blast; one photo showed a smouldering pile of wreckage with smoke rising from the debris and the setting sun, a fiery ball of orange, providing a poignant backdrop. Others showed the body of some of the men who died.
One of the men who died is believed to be the factory manager.
Local media have said there is concern another reactor in the building could explode next, and authorities have begun evacuating people from surrounding areas.
The injured have been shifted to a government hospital.
More details are awaited.
On Monday, a fire broke out at a cotton storage shed in the same district. Officials told news agency PTI the cause was a short circuit. The fire was brought under control and there were no casualties.
And last week a fire broke out at a food production unit in the district's Katedan industrial area. That incident took place on March 28. Six fire tenders were rushed to the unit, which made biscuits, wafers, and confectionary. Fortunately, no casualties were reported from this incident either.
With input from agencies