Firefighters deployed to a blaze on the 17th storey of an Ap Lei Chau residential block on Thursday raised a ladder from a fire engine only 45 minutes after the alarm was sounded, the Fire Services Department admitted yesterday. The early-morning blaze, which broke out in a flat at block 10 of South Horizons, injured seven people. A nine-year-old girl and her mother remained in serious condition last night. The crew, made up of 162 firefighters in 28 fire engines, spent three hours dousing the flames after realising the building's hydrant system was out of order. Angry residents blamed them for taking too long to get the blaze under control and reach them. A senior officer defended the operation, saying the faulty hydrants meant they had to concentrate on pumping water from the ground outside the block. Yeung Chung-hau, assistant director of fire services, said they received a call at 6.12am and arrived at the scene in four minutes. They initially fought the blaze from inside, Yeung said. The aerial ladder was raised only at about 7am, because "normally, there is no need to shoot water at the fire from outside the building", he told RTHK. Shooting water [at the flat] from the ladder will push the heat and smoke into the building. It will be dangerous to our colleagues fighting the blaze inside and the evacuating residents "If we really need to do so, we have to ask our colleagues inside the building to leave first … Shooting water [at the flat] from the ladder will push the heat and smoke into the building. It will be dangerous to our colleagues fighting the blaze inside and the evacuating residents." Firefighters later went up the ladder and aimed a water jet at the periphery, in order to prevent the flames from spreading to other flats. Yeung also said the defective hydrants were the only factor that lowered the efficiency of the operation. After they secured a steady water supply, a pump truck and a fire engine with the ladder took the shortest emergency path to get closer to block 10, he said, adding that the vehicles had no problem reaching the site. But the strong heat damaged the equipment of some of the firefighters and caused them to retreat briefly, he said. Sanjay Jayaram, 62, a retiree who lived opposite the burning flat, said he had met the occupant - a 21-year-old man - and his father, who was a retired fire officer. He said the son had told him he was sleeping but was awoken by the smoke and sparks from the air conditioner. The son tried to get water from a hose in the common area, but there was no water. He then triggered the alarm and knocked on all his neighbours' doors to alert them. The father was thankful that all the medals he had received for his excellent service as a fireman, and a book signed by former US president Bill Clinton, were intact as his room was locked. "He was sad his flat was badly burned, but he was happy he could keep those things," the retiree said. The kitchen was badly damaged, though, because the wind blew the fire in that direction. Officers returned yesterday to inspect the fire system but had yet to find out what had gone wrong. The system passed an annual inspection in July.