DENVER (KDVR) — Video shows a tent engulfed in flames on a downtown Denver sidewalk on Tuesday morning. It happened on 22nd between Curtis and Arapahoe streets.

No one was inside the tent at the time.

“It just burned to the ground,” said Mike Johnson, who recorded video of the tent fire. “It was very dangerous. If there had been any cars in the parking spaces next to it, they’d have definitely burned up.”

Alex Pacheco was on break from work nearby.

“I heard a really loud boom, and it took me a second to realize what was going on, and then I saw huge plumes of black smoke and the flames,” she said.

After firefighters doused the flames, Luis Alvarado started to sift through the rubble. He said he’d been staying in the tent in that location for about a month and had walked away. He said there was a candle and empty butane tanks inside the tent.

“I had two of those,” he said.

Dozens of fires reported among unhoused community

The Denver Fire Department said they have not determined a cause of the fire but said arson was being investigated and said it started around 9 a.m. They say to date, firefighters have responded to about 130 fires involving people who are homeless.

Denver firefighters say that compressed gases like propane or butane tanks are not allowed in the public right of way, and if seen, they will be confiscated. The city does outreach in the area to let people know about the dangers.

Video taken of the fire showed flames that were a few feet high before it was put out. As of 10:30 a.m., the fire had been put out.