Three adults and an infant were treated for carbon monoxide poisoning during a medical call to a residence in Otis Orchards early Thursday morning.
Firefighters responded to a residence on E. Eastland Rd. around 6:30 a.m. and were treating a 21-year-old woman when their carbon monoxide monitor started to sound an alarm.
Carbon Monoxide is a colorless, odorless, tasteless gas that can cause sudden illness and death without warning.
They began treating the woman, as well as two other adults and an infant, for carbon monoxide poisoning. All four were taken to local hospitals for further treatment.
The source of the CO is unknown, but Avista crews are at the residence working to determine the source.
The condition of the three adults and infant is not known as of 1 p.m.