NEW YORK (CBSNewYork) — An explosion caused a partial building collapse in Chinatown that sent eight people and four firefighters to the hospital Thursday afternoon.

The incident took place at 17 Pike St. near East Broadway. The area from East Broadway down to Henry Street was blocked off for hours, CBS 2’s Tracee Carrasco reported.

Apparent Gas Explosion Causes Partial Collapse Of Chinatown Building

Of the injuries, three were listed in critical condition, suffering from burns and smoke inhalation, EMS told WCBS 880. The firefighters’ injuries were listed as minor.

The cause of the explosion wasn’t immediately clear, but later investigators attributed it to improper use of bug bombs. The blast happened in a beauty salon in the rear of the building, 1010 WINS reported.

Firefighters could be seen pulling a man from the building into the bucket of a raised rescue tower ladder. The man did not appear to be conscious.

“We had a fire and an explosion on the first floor. We had minimum collapse but heavy fire on the first floor with extension to the second and third floor,” Fire Chief Robert Boyce said.

Building resident Tszkan Cheung said he heard a “boom, like a bombing, like an earthquake,” and saw firefighters carrying out a woman with a severely damaged leg.

“I almost freaked out and my heart was pounding really fast,” next door resident Jamie Lin, 12, told WCBS 880’s Peter Haskell.

“Heard the boom first and then see a fire and smoke come out,” witness Tao Ping Lin told Haskell.

John Sun said he was working on the first floor in one of the offices when he heard the explosion.

“I think like gasoline or something exploded. I feel very heavy thud like explosion and I just ran out. I have no idea what happened,” Sun told Carrasco.

Misty Lee lives on the fifth floor of the building and said she arrived home from school to the chaotic scene.

“I’m feel really bad about what happened to those people, but I’m just a little worried where am I going to stay,” Lee said.