The Rock Valley Fire Department in Rock Valley, Iowa, responded to reports of a strong gas smell inside the Rock Valley Assisted Living complex that had woken several residents. Firefighters initially suspected a natural gas leak, shut off the building’s gas valve, and entered with protective gear and monitors. No elevated natural gas levels were found, but dangerously high levels of carbon monoxide were detected, prompting the full evacuation of all 36 residents.
Multiple agencies assisted, including ambulance squads from Rock Valley and Hull, the Hull Fire Department, local police, the Sioux County Sheriff’s Office, and emergency management. Residents were kept warm in a school bus from the Netherlands Reformed Christian School while firefighters investigated. The source was traced to a vehicle left running in an attached garage—believed to have been accidentally left on by a resident returning from church after closing the garage door. The building was ventilated, gas service was restored by MidAmerican Energy, and all residents were safely allowed back inside around 1:45 a.m., with no injuries reported.