The cover of a ventilation unit fell from a Yau Ma Tei government office yesterday, hitting a pedestrian. Tang Kwok-hung, 31, was struck on the head at about 9.30am when the 33cm long plastic cover came free from the fan in the 12th-floor women's toilet of Canton Road Government Offices. Mr Tang was taken to Queen Elizabeth Hospital, conscious but bleeding from a head wound. He was in a stable condition. Senior Inspector Kwok Pak-chung, from Yau Ma Tei police station, said initial investigations showed the cover fell off when a 52-year-old female cleaning worker was repairing the fan. An Agriculture and Fisheries Department employee had complained it was loose. The cleaning woman was arrested for causing an object to fall from height. She was released on $500 bail and required to report back early next month. On Wednesday, Kwong Chor, 68, was hit by a piece of metal while shopping in Mongkok. Last Tuesday, lingerie hawker Liu Ngan-fong, 41, was killed when a piece of concrete fell from the roof of a 12-storey building in Mongkok.