Residents in Toa Payoh awoke to a fire that broke out in a Housing Board flat on Wednesday morning (Jan 10), after an explosion was heard. A photo sent by Straits Times reader Syed Hasanal showed black fumes rising up five storeys from the apartment on the 15th floor at Block 45, Toa Payoh Lorong 5. The freelance video editor said he was in his home at nearby Block 64 when he heard an explosion. "It was quite loud and didn't sound normal, like a big bang," said the 24-year-old. When The Straits Times arrived at the scene at around 10.35am, the unit's window looked charred and blackened. A fire engine and several police cars were parked below the block, next to a crowd of residents who had been evacuated from their homes. The Singapore Civil Defence Force (SCDF) said it was alerted to the fire at about 9.40am. Officers had to force their way into the flat as there was no one inside when the fire occurred. The blaze, which engulfed the flat's living room, was put out by firefighters using two water jets, said an SCDF spokesman. There were no reported injuries. An estimated 70 residents were evacuated by SCDF and police officers. The cause of the fire is under investigation, said the spokesman. A resident who lives on the fourth floor, Ms Dawn Tan, 23, said she woke up to a strong smell of smoke when her alarm clock rang at 9.30am. The undergraduate student woke up her brother Dexter Tan, 19, in a panic. "We've never seen a fire here before," said Mr Tan. "I didn't believe my sister at first, but we went down anyway." "There was already a fire engine here when they evacuated us," said Ms Tan, adding that she saw a crowd of onlookers below the block as she looked out her window. A 10th-floor resident, who wanted to be identified only by his surname Kong, said policemen rang his doorbell three times before he realised they were asking people to evacuate at around 10am. The 75-year-old retired odd-job worker woke up to the "smell of something burning", so he checked for any faulty electrical appliances in his home. He found none and realised the burning was happening upstairs. "I think a doctor lives in the flat, but he wasn't home, so they had to force open the door to put out the fire," said Mr Kong. The situation was calm when The Straits Times arrived, and the crowd of residents were shifted to the nearby Toa Payoh East Community Centre. At 10.38am, residents of the 14th floor and below were allowed to head back to their units.