Taiwanese officials set up an independent commission Friday to investigate the conditions at a run-down building in the port city of Kaohsiung where a fire killed 46, while authorities scoured the blackened ruins for the cause of the blaze.

Prosecutor Hong Ruei-fen told reporters at the scene she would seek to determine the cause of Thursday’s fire as soon as possible, before donning a hard hat and walking into the cordoned-off building in the morning.

Outside, a Taoist priest in traditional robes chanted a prayer for those who died, many of whom were elderly or infirm residents unable to get out of the 13-story building after the fire broke out on the ground floor.

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The city’s administration said the building had been required to follow fire codes and submit to inspections, but that inspectors had not been able to access the premises recently because the doors were always locked and they were unable to coordinate visits with the property owners.

Mayor Chen Chi-mai announced that he had ordered his deputy to set up an independent team to investigate whether negligence contributed to the tragic fire, in which another 41 people were injured.

Of the 46 dead, Chen said there were 21 who had still not been identified. He said experts hoped to use fingerprint analysis to determine who the other 19 dead were, but for two others they would have to rely on other methods.

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The building had commercial facilities on lower floors, a closed movie theatre, restaurants and a karaoke bar — most out of business — and some 120 housing units above.

The fire broke out in the lower area at about 3 a.m. Thursday, and witnesses reported hearing a loud sound like an explosion. It took firefighters until after 7 a.m. to fully extinguish the blaze.

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.

According to neighborhood residents, the building was home to many poor, older and disabled people, and many appear to have been trapped in their apartments.

Lee Mao-sheng, 61, who lives across the street, said his friend Tseng Yong-kang was wheelchair-bound and died in the fire.

In the past, the two would play mahjong together but Lee said he hadn’t seen his friend in a while because the door in the building’s elevator frequently didn’t open and residents didn’t have the money to maintain it.

“The people who lived inside, many of them were not in good health. Many of them had a disability,” Lee said. Cheap rent was the main reason people lived there under less than ideal conditions, he said.

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.

Tsai Hsiu-Chin, 70, who had lived in the building for 15 years, said she escaped with just the clothing on her back after hearing someone screaming “fire” at 3 a.m.

“I didn’t bring anything. I just cared about saving my life,” she said, sitting opposite the charred building on Thursday night, trying to process her experience over a beer with a friend.

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.

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.