LOS ANGELES (CBSLA) – A raging fire ripped through a commercial building in the Boyle Heights neighborhood of Los Angeles Wednesday, injuring several firefighters and destroying the structure.

About 150 firefighters were dispatched to the fire at the Passion Imports building in the 2800 block of E. Pico Blvd around 12:45 p.m.

Three firefighters were injured, including one critically, when the roof of the sprawling warehouse-type structure collapsed beneath their feet.

Plumes of thick, black smoke could be seen rising in the sky as crews battled flames.

The structure – a garment business – was believed to be a total loss.

Crews began pouring water on the structure and worked to vent the roof of the 16,000-square-foot building with initial reports indicating that as many as a dozen people might be inside, according to Los Angeles Fire Department Capt. Erik Scott.

A short time later, the roof gave way, and three firefighters who were on top of the building fell inside the burning structure, Scott said. All three suffered burn injuries, with one of them taken to a hospital in critical condition and the other two listed as fair, he said.

No other injuries were immediately reported.

Firefighters then assumed a defensive posture, pouring water on the structure from the outside. The blaze was declared knocked down around 3 p.m., but crews continued to spray water on the smoldering structure to prevent any flare-ups.

The Passion Imports website indicates the company specializes in apparel, accessories and souvenirs.

The business owner, Arun Dutt, told reporters at the scene that a crew of about 10 people had been inside the warehouse most of the day “changing the lights.”

“They were done almost, 60 percent, and then it starts — something happened in front of us and then they couldn’t control it,” he said.

At one point during the blaze, workers could be seen carrying what appeared to be propane tanks away from the burning structure.

The cause of the fire remains under investigation.

(© Copyright 2018 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)