POST FALLS - Monte Slinkard and Justin Harty were about to leave after shutting the power off, when the Avista employees sensed something was wrong.

Harty heard a generator running inside the little-used commercial building slated for demolition.

"Things didn't add up," Harty said.

The two, along with Avista's Dan Holden, who arrived a short time later, entered the building along Seltice Way between Post Falls and Coeur d'Alene through a rollup door. They found the generator hooked up to a travel trailer.

Thinking someone may be inside, they found out.

"It took several minutes of very loud knocking (on the trailer) for a man to wake up," Holden said.

It was a life-threatening situation as the air quality reading inside the building showed 450 parts per million of carbon monoxide. At 400 ppm, carbon monoxide can be life threatening in three hours, according to the Centers for Disease Control and Prevention.

"The man mentioned that he had been having headaches," said Holden. "He said he turned on the generator to take a nap."

The man, believed to be about 35, didn't say how long he had been sleeping or if he was living in the trailer. Holden stayed with the man for about an hour while he got some fresh air. Holden also told the man about the high carbon monoxide level.

"He said thanks for taking the time out to make sure that he was OK," Holden said. "He seemed groggy, but it was hard to tell if that was from the carbon monoxide or just waking up."

The Avista employees don't know the name of the man.

Greg Gfeller, Avista's director of operations in North Idaho, honored the three employees for going above and beyond the call of duty to detect the dangerous carbon monoxide level and waking the man.

"These guys could have easily just walked away," Gfeller said. "Their persistence made a difference. I'm really proud of them for sticking with it and the positive outcome."

Carbon monoxide is a colorless, odorless and poisonous gas that is produced when the combustion of any fuel takes place without sufficient oxygen. Overexposure symptoms include headache, fatigue, shortness of breath, dizziness and nausea.

"As temperatures fluctuate daily in the spring in the Inland Northwest, this situation is a good reminder of important gas safety guidelines for all residents when using propane heaters, barbecue grills and even warming up vehicles," an Avista press release states.