Six people were injured when an air conditioning equipment collapsed Saturday morning at the Gaylord Rockies Resort pool, where between 50 and 100 people were inside the aquatics center, Aurora authorities said.

All six were rushed to local hospitals, two of them suffering from life-threatening injuries, authorities said.

Aurora Fire Rescue said it received multiples calls that an HVAC system collapsed inside the pool area at the resort and dispatched several units, including a team that specializes in collapsed structures.

As it turned out, eight firefighters from nearby Aurora Fire Station No. 16 were already on scene, as they were conducting training at the Gaylord property and working in the stairwells there.

Aurora authorities said this allowed a quicker response by highly trained paramedics and EMTs, who immediately went to the pool to assist patients.

“I would like to share that the men and women of this agency train for this type of incident every day,” said Aurora Fire Chief Alec Oughton. “I am proud of their rapid and effective response in caring for our community.”

Oughton said it’s not clear what caused the collapse at this point, and that an investigation will be conducted by Gaylord Rockies, not Aurora Fire.

In a statement, city officials said they expect a “thorough” investigation into what happened and why.

“Our hearts go out to all those who were injured today, to their families and to those traumatized by witnessing what occurred,” city spokesman Ryan Luby said on behalf of Aurora’s mayor, council and staff.

“We expect a thorough investigation, and our immediate focus is the well-being of those involved, and we thank our first responders for their quick response and care,” he said.

According to the hotel’s booking site, the pool was closed for maintenance recently, and it’s not clear when it reopened.

“We don’t have any information on what led up to the collapse. There will be an investigation,” Oughton said. “That’ll be all the Gaylord’s responsibility. It’s not a fire department investigation. But I know they have an interest in looking into what happened and getting to the bottom of it.”

A spokesperson for Gaylord Rockies declined to comment, saying that the Aurora Fire Department was investigating. 9NEWS had asked Gaylord Rockies for clarification on who is investigating the collapse.