KARACHI: Two men died after inhaling toxic gases while cleaning an underground water tank of a residential project in Gulistan-i-Jauhar whereas four persons, who attempted to save their lives, became unconscious, rescue services officials said on Thursday. Rescue-1122 official Hassaan Khan told that two employees of housing project Falak Naz, located in Block-18, went down a large underground water tank for its cleaning. However, they were not properly trained and entered the tank without masks or protective gear, Mr Khan added. And as they did not come back for a considerable time, four other persons, also employees of the high-rise building, went inside the tank to save them but they also became unconscious. Realising the gravity of the situation, the residents approached Rescue-1122 for help, the rescue official said. He said Urban Search and Rescue Team along with a disaster response vehicle and ambulance arrived at the spot and started the search operation. The people were rescued and sent to a nearby private hospital where two of them, identified as Moid, 40, and Ahmed, 30, were declared dead on arrival while Sartaj, 20, Haider, 25, Noor, 27, were admitted for treatment. The fourth one was a minor who was provided first aid on the spot by the rescue team. Their deaths were apparently caused due to toxic gases in the underground water tank, Mr Khan opined. The rescue team members cleaned the tank from toxic gases after the incident, he told. A private security guard was shot dead in an ‘accidental fire’ in the Defence Housing Authority on Thursday. Sahil SHO Iftikhar Arain said the rifle of Muhammad Noman, 30, went off “accidentally” at Zulfiqar Commercial. As a result, a bullet hit his chest and he died. He was the guard of an under-construction bungalow. The body was shifted to the Jinnah Postgraduate Medical Centre for medico-legal formalities.