A commonly reported cause of death in several fire accidents is asphyxiation, with smoke killing people even before fire engulfs a place.

Doctors say this is because of deficient supply of oxygen to the body, damaging the lungs and blocking the airway. When oxygen supply is cut off to the body, vital functions begin to shut down resulting in death, the doctors say.

Shashidhar Buggi, director of Rajiv Gandhi Institute of Chest Diseases, says people can die of suffocation even if the fire is outside the building. “This is because the smoke that enters the building pushes out oxygen and fills up the building with poisonous gases. Smoke contains carbon dioxide and carbon monoxide apart from various hydrocarbons. Inhaling these gases blocks the airways and leads to suffocation,” he says.

Mohan Rao, professor and head of the Department of Pulmonology at M.S. Ramaiah Medical College and Hospital, says brain damage or death of those trapped in a building overrun bysmoke depends on the speed at which the smoke spreads and the person’s health.

“If the person is near the fire and the resultant smoke is thick, damage can occur sooner,” he says. “Apart from carbon dioxide, carbon monoxide, sulphur dioxide, smoke can have noxious and nitrogenous gases. Besides, it can also contain other poisonous gases depending on what has been burnt in the fire,” he says.

More In: Bangalore