Fire-truckCarbon monoxide levels at least seven times higher than what’s considered dangerous were reportedly found in a southwest Iowa motel on Sunday.

Authorities say a paramedics treated a 15-year-old male and a 37-year-old female with oxygen while they were being were transported to the hospital in fair condition, after CO2 levels in the pool area at the Quality Inn and Suites in Council Bluffs spiked and resulted in several other people feeling nauseated.

At least two people were treated with oxygen at the motel. Rescue crews responded to the scene at around 3 p.m. and evacuated the motel after discovering a pool heater malfunctioned, causing the carbon monoxide levels to rise to dangerous levels. Experts say CO2 levels above 70-parts per million can cause headache, fatigue and nausea. Levels at the hotel were reportedly at 500-parts per million.

(Reporting by Ric Hanson, KJAN, Atlantic)