Krishna Swamy (59), who had suffered 82 per cent burns and was undergoing treatment at Apollo DRDO Hospital, died at 5.30 pm, a release from the private hospital said.
Eleven others are still undergoing treatment at the hospital and three of them are in critical condition, it said.
The blast and subsequent fire occurred at Explosives Division of the private company on February 23 when some detonators were being disposed of.
Cyberabad Police had earlier registered a case under IPC Section 304A (causing death by negligence), 337 and 338 (causing hurt by act endangering life or personal safety of others) against the company management and started a probe into the cause of the explosion.