SHANGHAI — Chinese authorities detained four people after determining that unlicensed welders may have been responsible for a fire that engulfed a high-rise apartment building undergoing renovations, killing at least 53 people and injuring at least 90 others in one of the deadliest fires here in years, according to Xinhua , the official news agency.
Video posted on the Internet and some online accounts suggested that some residents were trapped on the roof of the building and that a few may have jumped to their deaths. Three helicopters tried to rescue residents from above, but flames and thick black smoke hampered the efforts, Xinhua said. Some people clung to scaffolding; some were able to climb down.
Local officials said that 180 families lived in the building and that many residents were retired teachers, state-run media reported. Many people remained unaccounted for.
The fire raged for more than four hours and more than 60 fire engines responded, Xinhua reported, but fire hoses could not reach the upper half of the 28-story building. Only when hoses were set up on top of a nearby building, it said, could the fire be contained.
According to Xinhua, the fire was started by unlicensed welders and four people have been detained. The state-run Web site Eastday.com cited a construction worker as saying that crews were installing energy-saving insulation when the fire occurred, The Associated Press reported, and a witness told Xinhua that he saw construction materials burning before the fire. The building, constructed in the 1990s, was nearly covered by scaffolding. Many residential buildings in Shanghai lack sprinkler systems, but it was not yet known whether there were sprinklers in the building that burned.
“I saw at least four or five people hanging onto the scaffolding which covers the building, screaming for help,” said Li Qubo, who works nearby, according to China Daily, an English-language newspaper. “Firefighters were trying to get closer and use their hoses to cool a path on the scaffolding so that they could climb down and escape.”
The reports deepened the unease in this city of 20 million, most of whom live in high rises. Against the backdrop of a nationwide construction boom, buildings all over the city are under construction or renovation.
Scores of survivors were being treated at hospitals for smoke inhalation and other injuries. At one hospital, The A.P. reported, the father of a 30-year-old resident said: “She called her husband and said: ‘It’s on fire! I have escaped from the 22nd floor to the 24th floor,’ but then the phone got cut off. That was the last we heard from her.”
Firefighters were similarly frustrated in Beijing in February 2009, when an illegal fireworks show set off a ferocious fire that destroyed a building as it was nearing completion. With hoses unable to reach more than about a dozen stories, the 34-story building burned all night. Meant to house a hotel and cultural center, it was part of a complex designed by the Dutch architect Rem Koolhaas as the headquarters of the state television network CCTV.
China's  said Tuesday that at least 53 people were killed in Shanghai during a deadly fire. The blaze, which occurred on Monday at 2:15 p.m.  (0615 ), consumed a 28-story high-rise apartment building in the city's .

The building was being renovated at the time of the fire, and was home to over 150 families. At least 100 victims have been admitted to area hospitals, although some later died. Most survivors were not seriously injured, but needed treatment for . Firefighters were still looking for survivors and over 70 were still hospitalized on the morning after the fire.

The fire was the worst in recent Shanghai history and took over 100 fire engines more than four hours to contain. Strong winds blew heavy smoke into the air, hampering rescue efforts by helicopters. The smoke was seen by witnesses around 15 kilometres (9.3 miles) away from the high-rise. The fire was largely extinguished by 6:30 p.m. local time (1000 UTC), allowing fire and rescue officials to enter the building.

The apartment building, built in the late 1990s, was home to mainly retired teachers. Some residents climbed down the scaffolding to escape, while others called for help but were unable to flee the blaze. "I saw at least four or five people hanging onto the scaffolding which covers the building, screaming for help," said Li Qubo, who was working near the high-rise.

The cause of the fire has not yet been determined, but local residents said fire safety regulations were not strict, and workers often tossed used cigarettes into the building's hallways. Qiu Jingshu, a 38-year-old worker who was outside the 18th floor when the fire struck, said he saw sparks from welding being done on an adjacent building fly over onto the high-rise. The sparks lit up foam on the scaffolding around the apartment, according to Qiu. "We had tried to put out the blaze, but the fire was so big and spread so quickly that we could barely escape ourselves," he said. Crews were said to have been installing insulation at the time of the fire, and witnesses saw construction materials on fire before the building was overtaken by flames.

Two nearby buildings were evacuated, and their residents were temporarily sent to local hotels, and a school. , China's , said that an investigation would determine who was responsible for the fire, so they could be punished accordingly. Meng said that a team had been formed under  to look into the disaster.

A similar incident occurred in Beijing early last year. In February 2009, the illegal use of fireworks  that gutted a 34-story building under construction at the time.

Shanghai has a population of about 20 million, housed mainly in high-rise apartments. Many buildings in the city are under construction or being renovated.