May 7 (UPI) — Six people were injured, including two critically, when mechanical equipment collapsed into an indoor pool in Aurora, Colo.

First responders were called to an incident at the Gaylord Rockies Resort and Convention Center at about 9:50 a.m. on Saturday. Heating, ventilation and air conditioning had collapsed from above the indoor pool and fallen on several people below, according to a press release by Aurora Fire Rescue.

Two of the victims suffered life-threatening injuries. Six people were transferred to hospitals. The agency estimates that 50 to 100 people were inside the aquatic center at the time.

Multiple rescue teams responded to the scene, including Aurora Fire Rescue’s Technical Rescue Team which specializes in incidents with collapsed structures. There were also eight firefighters on site at the resort conducting training exercises.

The Technical Rescue Team ensured the safety of other first responders by assessing the scene and looking for more equipment that could potentially fall, according to Aurora Fire Rescue.

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

The Gaylord resort will be responsible for investigating the incident, Oughton told CBS News Colorado.

“We don’t have any information about what led up to the collapse,” Oughton said during a press briefing.

Oughton said he did not have information whether those injured were adults or children.