The mobility of smoke and the lethal gases it contains makes smoke more dangerous than the fire that created it.

Smoke can travel throughout a building in a short period of time, while a fire may be contained in only one room, said Reuben Nelson, assistant chief at the DeKalb Fire Department.

One of the most dangerous gases released by fire is carbon monoxide.

Carbon monoxide displaces oxygen in the blood, said Dr. Vivek Thappa, pulmonologist at Kishwaukee Community Hospital. Without oxygen, the body and brain do not function properly, he said. If awake, a person will feel groggy and suffer decreased mental function. If the victim is asleep, the effects go unnoticed.

“If there’s a fire in your house, you’re probably not going to wake up,” Nelson said.

As the fire burns, it consumes oxygen, compounding the effects of carbon monoxide poisoning.

“If they finally do wake up, they’re toxified,” Nelson said. “I’ve seen it where a person wakes up but can’t find the way out of their room; they’re disoriented. That’s why a smoke detector is so important.”

With a smoke detector between the living quarters and sleeping quarters, a person will be alerted to any danger before the smoke becomes too intense, Nelson said. Also, closing doors will keep much of the smoke from spreading to bedrooms and give people extra time that may save their lives, he said.

If a victim is near enough to the fire, hot gas can physically damage the airway and lungs, Thappa said. Beyond the primary danger of burns, inhaling hot gas has lasting effects.

“Damaged tissue in the upper airway can predispose you to infections,” he said. “If it’s very hot, it can burn lung tissue.”

Other toxic gases will be released in the smoke depending on what is burning, Nelson said. Especially harmful are gases released by burning furniture, electronics and carpet, he said.

“In my 25 years, I’ve seen 18 fatal fires. Every single one of those was due to smoke inhalation,” Nelson said.

Even if a victim is burned badly in a fire, the likely cause of death will be smoke inhalation, he said. The smoke kills the victim before the fire reaches them, and then the body is burned, he said.