Mumbai. According to the naval board of inquiry, the fire was caused due to problems in the cables of the vessel. This particular incident led to the resignation of Chief of Naval Staff (CNS) Admiral D K Joshi on 26 February, who owned moral responsibility for the incidents in the past few months. March 2014: While in Mumbai, had a malfunction on board which led to a toxic gas leak killing Commander Kuntal Wadhwa. According to the Indian Navy, the ship suffered a malfunction in its carbon dioxide unit while undergoing machinery trials, leading to gas leakage. Since the ship was not commissioned at the time of the incident, the enquiry into the mishap will be done by Mazagon Dock Limited, where the ship was constructed. March 2014: One civilian worker was killed and two people were injured in an accident in Vishakapatnam where India was building its nuclear ballistic submarines. The incident took place when the pressure of the hydraulic tank of the Arihant class submarine was being tested and the tank's lid fell on the workers at Building-5 of the shipbuilding centre. May 2014: suffered a minor explosion in the boiler room while undergoing a refit at the Mumbai dockyard. Four people suffered minor injuries. There was no fire and no equipment was damaged. November 2014: Indian Navy's Astravahini-class torpedo recovery vessel TRV A 72 sank off Vishakapatnam during a routine exercise on 6 November; one sailor was killed during the rescue and four were missing, feared dead. The auxiliary ship sank to a depth of about 370 meters, about 35 nautical miles south of Visakhapatnam and 28 nautical miles from the closest point of the coast. At the time of incident there were 28 personnel on board of which 24 were rescued by naval ships. The main cause of the accident was indicated as cracks in the seals attached to the shaft, which allowed in seawater and resulted in flooding This was one of 24 accidents in the previous 3 years involving Indian naval ships and submarines reported in the Rajya Sabha by the Defence Minister in response to a query April 2016: A sailor lost his leg while two others were injured in an oxygen cylinder explosion on board . The explosion took place on 16 April while a diving bailout bottle, a small oxygen bottle that is carried by divers in their diving helmet, was