Denver construction site fire impacts nearby businesses; Investigators still trying to determine cause

Smoke still fills the sky off Leetsdale Drive in Denver as firefighters wash down what they can, and people can't help but stare at the pile of debris. On Friday night, the apartment complex that was still under construction was engulfed in flames.

The fire was just across the street from Inga's Alpine Bar, where Peter McKnabb was working at the time.

"I have not seen a fire like that, ever, that up close. It was- it was massive," McKnabb said.

According to the architect's website, the nearly 300-unit Harker Heights apartment building was set to open in May. The developer, EMBREY, told CBS News Colorado they were working to gather all details of what happened at the site the day of the fire.

The Denver Fire Department says that a security guard was at the property at the time of the fire, but a passerby is the one who called 9-1-1. DFD says emergency crews were at the complex within minutes.

"I had customers rushing out," McKnabb said. "Shortly after, the fire department, police- they started evacuating all of us."

The fire demanded more than 150 firefighters from at least three different agencies. With hard to hard-to-reach hot spots under the debris, DFD expects to keep working at the site over the next few days. Meanwhile, McKnabb says Igna's temporarily lost power due to the fire and says they are still without the internet and only able to accept cash payments as traffic impacts slow business. McKnabb also says that while police asked them for any security footage of the fire, the outage has temporarily blocked their access to that footage.

A nearby home's siding was also partially melted from the heat. Denver Fire also says they're aware a firework may have gone off nearby as the building burned.

In a press conference Saturday, Denver Fire Division Chief of Operations Robert Murphy said, "Multiple portions of this building have collapsed. We are still unable to get inside to do any searches, which would help us determine a cause and also search for any potential victims that are inside."

On Sunday, the building's developer EMBREY did not confirm what was happening at the site before the fire, but spokesperson Jeff Cowart sent the statement: "Our entire team would like to express our deep gratitude to the emergency response teams from around the city who worked to contain the fire within the construction site and who continue to work to secure the site. Our priority remains working collaboratively with Denver Fire, investigators, and the community as the investigation continues to determine the cause and next steps."

DFD says they likely will need the building torn down to extinguish every hot spot, but they are not yet sure who is paying for that demolition. DFD hopes fire investigators can see more of the building this week before any of that happens.

As traffic delays continue, McKnabb hopes customers will continue to come in: "Clean it up fast. Open the road up. We're still here. That's all that really matters, is that people still know, you know, Inga's is here."