LOS ANGELES – Four firefighters injured in a fiery explosion in the downtown Los Angeles Toy District over the weekend remain hospitalized on Tuesday.

What You Need To Know

  • Fiery explosion left 12 firefighters injured

  • Investigation launched to determine cause of the fire

  • Butane canisters were found inside the building

  • Police describe this area of LA as “Bong Row”

Eleven firefighters were hospitalized with burn injuries after a "massive fireball'' engulfed them during the explosion Saturday, according to the Los Angeles Fire Department. A total of seven have been released.

A GoFundMe account has raised nearly $40,000 of its $60,000 goal to assist the family of LAFD Capt. Victor Aguirre, who was injured in the explosion. The money will be used for long-term bills, as well as to bring meals to his wife and children, who are staying at a hotel near where he was hospitalized. It was not immediately clear if Aguirre was one of the firefighters who was released on Monday and Sunday.

Los Angeles Fire Department's arson and counter-terrorism unit, and the criminal conspiracy section of the Los Angeles Police Department's Major Crimes Division were in charge of the probe, fire department spokesman Nicholas Prange said. The Los Angeles Times reported that the Federal Bureau of Alcohol, Tobacco, Firearms and Explosives was also working on the investigation.

Carbon dioxide and butane canisters were found inside the building but it's unknown if they contributed to the explosion, Prange told City News Service.

“The investigation is in its preliminary stage right now,'' Prange said. “So there are no details that can be reported yet.''

The explosion happened about 6:30 p.m. Saturday while firefighters responded to the initial call of a fire in the single-story building at 327 Boyd St., between East Third and Fourth streets. The business was called Smoke Tokes Warehouse Distributor, “a supplier for those who make butane honey oil,'' according to LAFD Capt. Erik Scott.

Firefighters had begun an offensive battle inside the building when there was an explosion and multiple buildings became involved, Scott said.

“There was a significant explosion that caused a mayday report,'' Scott said. “This was upgraded to a major emergency category.''

Some of the 11 firefighters suffered “obvious damage and burns'' in the explosion and were taken to County USC Medical Center, he said. Three firefighters with the Los Angeles Fire Department were released from the hospital Sunday, while eight others remained hospitalized, Prange said.

Two firefighters are in critical, but stable condition. A twelfth firefighter was treated and released from an emergency room Saturday for a minor extremity injury, he said.

Dr. Marc Eckstein, medical director for LAFD and a physician at County USC, said they all arrived at the hospital awake and alert, but two firefighters were put on ventilators due to smoke inhalation and four were sent to the intensive care unit for burns. Most of the burns, he said, were on their upper extremities.

Mayor Eric Garcetti said, “The good news is that everybody is going to make it,'' but he added, “We have a lot of firefighters who are shaken up.''

LAFD Chief Ralph M. Terrazas said the mayday call, which is used only when a firefighter is “down, missing or trapped,'' was “the kind of call I always dread.''

He said the injured men, who were from Engine No. 9, realized something was wrong when they were inside the building but could not escape in time to avoid the blast. Their fire engine parked outside was charred, and the aerial ladder was damaged -- with eyewitnesses saying firefighters on that ladder climbed down with their coats on fire.

Multiple ambulances and fire companies were called to the scene, with more than 230 firefighters responding and establishing a treatment area east of the building. The fire, which spread from the narrow one-story building where it originated to neighboring businesses, was knocked down at 8:08 p.m. The cause of the fire “is of paramount concern,'' Scott said.

Earl King, a 64-year-old man who lives in an alley a block away from the building that went up in flames, said at first the smoke was so minor he thought it was just a trash can fire.

“The smoke was getting bigger,'' he said. ''And then all the sudden there was a big 'ole popping sound...POP, POP, POP...That's when, BOOM! And then we can feel it -- you know that little vibration.''

The sound reminded him of a large train chugging right toward him, he said.

“It scared the hell out of me,'' he said. “And then when we looked up we seen all the smoke, and the ashes coming down with fire on 'em.... It was no joke. It was no joke.''

He said the blaze seemed to be in a complex that includes a vape shop warehouse where he's worked as a day laborer before.

“We be doing their containers,'' he said. “You know, unload their truck.''

King said when he was working in the building he noticed plenty of flammable materials.

“A lot of those warehouses have chemicals, you know the stuff, like butane for lighters, or whatever,'' he said.

Police described the area where the explosive fire occurred as “Bong Row'' because of a large number of cannabis, CBD and pipe businesses, the LA Times reported.