Columns of thin smoke were still rising from the upper house of the Egyptian parliament on Wednesday, a day after a fire gutted much of the three-story palace, including the 19th century building's historic halls and its archives, AP reported. Egypt's general prosecutor has opened an investigation into the cause of the fire. Initial reports suggested that a spark during maintenance work on Tuesday afternoon might have ignited the blaze, a security official said. He spoke on condition of anonymity because he wasn't authorized to speak to the press. One firefighter is missing and believed to be dead, a security official said. At least 16 workers and firefighters were hospitalized for smoke inhalation and other minor injuries, said Ahmad Salah, the fire operations supervisor. Firefighters on truck-mounted cranes directed water hoses on the building throughout the day to «cool» the wood to try to prevent the fire from re-igniting, Civil Defense Gen. Mohammed Nousser told the state-run news agency, MENA.