CO – Four people were hospitalized early Tuesday when their home was filled with carbon monoxide and two were found unconscious.

Assistant Chief Cory Huwa of the Southeast Weld Fire District station in Prospect Valley said the firefighters were called shortly after 9 a.m. Tuesday to the home at Weld County roads 65 and 16.

Three adults and one child were in the house, and Huwa said no names were available. A 44-year-old woman was taken by helicopter to St. Anthony’s Hospital in Denver. A man, 50, another woman, 30, and a 5-year-old child were taken to North Colorado Medical Center in Greeley. Conditions of the four were not available, but Huwa said he believed they would all recover.

The older woman and man were in the house overnight and received the most exposure to the gas. The 30-year-old woman apparently came home early in the morning with the boy, so they had less exposure.

Carbon monoxide is an odorless, invisible gas that can kill if there is enough present in a house or car. Symptoms include nausea, headaches and loss of consciousness.

Huwa said the cause of the gas exposure in the house hasn’t been determined, but the furnace was being checked for possible leaks.