Authorities are investigating what caused the dangerously high levels.
One child is dead and at least five other children are hospitalized after they reportedly suffered carbon-monoxide poisoning at an indoor-pool in Michigan.
According to the authorities, staff at the local Quality Inn and Suites in Niles found six children laying on the pool deck unconscious and unresponsive on Saturday around 10 a.m.
Fire Department Capt. Don Wise said it’s not clear how long the children, ages 12 to 14, were in the area where they were found.
Hotel officials immediately opened windows and called police. The children were transferred to local hospitals where one was pronounced dead on arrival.
“When we first went in with our [air] monitors, the monitors went off,' Wise said, according to ABC News. “All the responders took a little bit more risk, but we had to get those kids out of there and into fresh air for their best chance at survival.”
A total of 12 people, including hotel staff and officials, were transferred to the hospital.
The hotel was also evacuated.
The carbon monoxide levels in the hotel were reportedly 16 times the safe limit, reports said.
"That’s an extreme danger level," the fire captain told reporters. "At those levels, they don’t have much time before they're going to go unresponsive."
Read: Hunters Discover and Save Unconscious Children Poisoned by Carbon Monoxide
Authorities are investigating what led to the dangerously high levels of carbon monoxide in the pool area.
There were also high levels of carbon monoxide in other areas of the hotel, although not as high as in the pool area.
Watch: 4 Kids Killed After They Are Poisoned From Black Market Pest Control Chemical
