An explosion at a residential building in Beijing early on Friday killed one woman and injured eight other people.

The reason for the explosion was under investigation, but residents suspected it was related to a hydrogen tank used by a hardware store adjacent to a bottom-floor apartment.

The blast occurred at around 5:30 am in the Zuojiazhuangbeili community in Chaoyang district.

Rescuers found an injured elderly woman at around 8:10 am and rushed her to a hospital after providing emergency treatment at the scene. She died later at the hospital.

One of the eight who were injured was in serious condition, but the injuries did not appear life-threatening, according to medical personnel.

Scaffolding had been erected all around the building as part of a project to install fireproof material on the its exterior surface, residents said.

The explosion bent the scaffolds outside the windows and doors of the apartment, and damaged windows and doors. At least five vehicles parked nearby were also damaged, with most of their glass broken.

A large piece of the coating layer of the apartment's internal wall fell off. Part of the external wall was cracked.

Debris, including broken windows and doors, twisted metal, furniture and bricks were scattered around in the apartment and in the street in front of it.

The force of the blast was so massive that it bent the gate of an opposite building opposite about 50 meters away, and it displaced the security door of an apartment on the building's ground floor.

A lot of glass in nearby buildings was shattered.

Lu Hua who lives on the first floor of a nearby building said she had never heard a bigger sound before.

"I remember the sound of artillery from the Japanese invaders. The sound of this explosion was even bigger," the 79-year-old said, adding that the building shook as though it were in an earthquake.

"I was so frightened that I almost collapsed, and my legs still tremble now if I stand up," Lu said five hours after the blast.

Hou Jun, Lu's grandson, said the explosion forced open the door of his home, though he had locked it the night before.

Hou said the ceiling of his house cracked, and several window screens fell.

Li Jianmin, who runs a fruit stand just outside, said he was sleeping in his van only 5 meters away from the blast site.

"All of my van's glass was broken, and I had to creep out of the vehicle through the window because I couldn't open the door," the 25-year-old said. "The whole building was engulfed in white smoke when I came out."