Mumbai: India’s Navy on Friday said two of its sailors and two civilian dockyard workers were taken to hospital following an explosion on the Indian Naval Ship (INS) Ganga in the Mumbai Dry Docks where it was undergoing repairs and a refit.

Authorities said a loud noise was heard at about 11.15am on Friday in the boiler room of INS Ganga and added that “the cause of the loud noise was possibly due to gas accumulation.”

Although several news reports said there was a fire and some naval personnel were injured, a release from the Ministry of Defence stressed that “there has been no fire or any damage to any equipment in the ship. Two sailors and two civilian dockyard workers were taken to hospital only for precautionary check-up and have been immediately been discharged. The situation is normal.”

Earlier news reports, quoting naval sources, said that during welding work, the welding gun took time to ignite and when it did, thick flames erupted from the gun, injuring three people including two civilians. They sustained burns and were taken to the naval dispensary for first aid.

The INS Ganga is a Godavari-class guided-missile frigate built in Mumbai by Mazgaon Dock Limited and commissioned on December 30 1985. The ship was deployed for patrolling in the Gulf of Aden to protect the marine jurisdiction from Somali pirates.

Though the incident may be minor, a string of nearly 10 mishaps involving the Navy’s ships and submarines over the last year has become a matter of concern.

The latest incident comes only a few days the new Chief of Naval Staff Admiral R.K. Dhowan said that the Indian Navy had taken a serious note of the recent accidents involving its submarines and investigations were underway.

In March 2014, a toxic gas leak in the INS Kolkata, which was under construction at Mazgaon Dock, killed Commander Kuntal Wadhwa instantly.

A month earlier in February, a fire on board the INS Sindhuratna, a Kilo-class submarine, resulted in smoke leading to suffocation and death of two officers. Seven sailors were also injured and they were airlifted to the naval hospital in Mumbai.

This particular incident led to the resignation of Chief of Naval Staff Admiral D.K. Joshi who owned moral responsibility for the incidents.

Other incidents include naval ships colliding with a fishing trawler, hitting a jetty, running aground and a hole in the pillar compartment of the INS Vipul forcing the ship to return to harbour.

The worst incident was in August 2013 when blasts ripped through the torpedo compartment of the submarine INS Sindhurakshak while it was berthed at the naval dockyard in Mumbai. Fifteen sailors and three officers were killed.