The ventilation system in the kiva was composed of a ventilator shaft, a ventilator tunnel, and a roof hatchway. This system brought fresh air into the room, and assisted in the removal of smoke created when the Anasazi burned a fire in the hearth. In spite of this system, however, the air in the kiva was probably often stale and smokey, especially during bad weather when the hatch cover was pulled over the hatchway.