TAIPEI — Officials in Taiwan were pursuing leads Friday into the cause of a fire in a run-down mixed commercial and residential building in the port city of Kaohsiung in which 46 people were killed and another 41 injured.

The fire in the 13-story building that was home to many poor, older and disabled people broke out early Thursday and raged for hours; reports AP.

Witnesses said they heard what sounded like an explosion at about 3 a.m. when the blaze erupted in the building’s lower floors, which housed abandoned restaurants and karaoke clubs.

On Friday morning, a wire mesh fence and supporting scaffolding cordoned off the building and the street in front was open again to traffic.

The building did not seem in immediate danger of collapse, though its lower floors were blackened and smoke marked the exteriors of the upper apartments. It took firefighters until after 7 a.m. to extinguish the blaze, while thick smoke enveloped the upper floors.

The building’s age and piles of debris blocking access to many areas complicated search and rescue efforts, officials said, according to Taiwan’s Central News Agency.

The decades-old apartment building is one of many in the Yancheng district, an older part of Kaohsiung, a city of some 2.8 million people in southwestern Taiwan.

Local media say police were questioning a female resident of the building who allegedly discarded a burning incense coil in a trash can inside the apartment where she had also stored small gas canisters.

A man who carelessly discarded a cigarette outside the building and the possibility of a fire in the electrical system were also being investigated, the reports said.

Kaohsiung Mayor Chen Chi-mai said the investigation would include issues of "administrative responsibility." He spoke to reporters at a city funeral home where traditional Buddhist and Taoist ceremonies were being held for the dead.

Fire extinguishers had been installed last month, but only three per floor because the residents could not afford to pay more, the United Daily News, a major newspaper, reported.

A 1995 fire at a nightclub in Taichung, Taiwan’s third-largest city, killed 64 people in the country’s deadliest such disaster in recent times. — Agencies