Smoke inhalation and carbon monoxide poisoning first aid¶

Smoke inhalation and acute carbon monoxide (\(\text{CO}\)) poisoning are the leading causes of death in indoor structure fires and heating emergencies, claiming three times as many lives as external flame burns. When household furniture foam, synthetic carpets, plastics, wood, or fuels burn or smolder inside an enclosed room, they release superheated gases (\(150^\circ\text{C}\text{ to }500^\circ\text{C} / 300^\circ\text{F}\text{ to }900^\circ\text{F}\)) that scorch the upper throat alongside lethal concentrations of invisible systemic poisons: carbon monoxide (\(\text{CO}\)) and hydrogen cyanide (\(\text{HCN}\)). Because a person who walks out of a smoke-filled building or carbon monoxide leak can appear alert initially and then collapse 30 minutes later as their scorched windpipe swells shut or cellular hypoxia peaks, rapid fresh-air extraction, upright airway positioning, and immediate 100 percent high-flow oxygen from paramedics are critical.

This guide walks you step by step through safe victim extraction without becoming a second casualty, recognizing impending thermal airway closure (stridor), why fingertip pulse oximeters give fatally false 99% readings during carbon monoxide poisoning, performing CPR with rescue breaths for asphyxial arrest, and monitoring for delayed fluid in the lungs over the next 48 hours.

Do this now¶

1. Protect yourself first , never enter a burning or CO-filled enclosed space without breathing apparatus. Do not run back inside a smoke-filled building, basement, or closed garage with a running generator or car. Invisible carbon monoxide and hydrogen cyanide can knock a rescuer unconscious in two breaths. Only pull a victim out if you can reach them immediately from an open doorway while staying low below the smoke layer.
2. Move everyone into fresh outdoor air at least 15 to 30 meters (50 to 100 feet) away. Get the person completely out of the building (not just into a hallway or open garage) into open, circulating outdoor air away from smoke plumes or exhaust vents.
3. Call your local emergency number immediately and request high-flow oxygen. Call your local emergency number (911 in the United States and Canada, 112 across the European Union, 999 in the United Kingdom) or check our emergency numbers directory. Tell the dispatcher specifically that you have a smoke inhalation or carbon monoxide poisoning victim so they dispatch paramedics equipped with 100 percent oxygen non-rebreather masks, intubation gear, and Cyanokit (hydroxocobalamin) antidotes.
4. Check responsiveness and position the airway properly:
   • If conscious and breathing: Seat the person upright or semi-upright at a 45-to-90-degree angle (leaning slightly forward on their knees if short of breath). Sitting upright uses gravity to slow down throat and vocal-cord swelling.
   • If unconscious but breathing normally: Roll them onto their side in the Recovery Position so their tongue does not block the windpipe and any vomit drains out of the mouth.
   • If unresponsive and not breathing (or only gasping): Start CPR immediately with 30 chest compressions followed by 2 rescue breaths.
5. Loosen tight clothing around the neck and keep the person completely still. Unbutton shirt collars, ties, belts, and jackets, and do not let the person walk around or exert themselves. Physical movement increases heart rate and oxygen consumption, circulating carbon monoxide and cyanide faster into the heart muscle and brain.
6. Give NOTHING by mouth (no water, ice chips, or food) if they inhaled hot smoke. Even if the person's throat feels dry and burned, do not let them drink water; swallowing through a blistering larynx can trigger sudden fatal vocal-cord spasm (laryngospasm) or cause deadly vomiting when paramedics insert an emergency breathing tube minutes later.

Immediate smoke inhalation and CO first-aid decision flow¶

Follow this clinical sequence from the moment you encounter a smoke or carbon monoxide casualty.

flowchart TD
    A["Person Exposed to Fire Smoke, Exhaust, or Carbon Monoxide Alarm"] --> B{"Is It Safe to Reach the Victim Without Entering Heavy Smoke or Confined Gas?"}
    B -->|"No: Active Fire or Confined Lethal Gas"| C["Stay Outside, Open Exterior Doors From Outside if Possible, and Call 911 / 999 / 112 for Firefighters"]
    B -->|"Yes: Safe to Extract"| D["Move Victim Immediately to Fresh Outdoor Air (15 to 30m / 50 to 100 ft Away)"]
    D --> E["Call 911 / 999 / 112 Immediately: Report Smoke Inhalation / CO Poisoning for 100% Oxygen"]
    E --> F{"Is the Victim Conscious and Breathing Normally?"}
    F -->|"Unresponsive & Not Breathing (or Gasping)"| G["Start CPR Immediately: 30 Chest Compressions + 2 Full Rescue Breaths"]
    F -->|"Unconscious, But Breathing Steadily"| H["Roll Onto Side in Recovery Position (Prevents Vomiting Aspiration) & Watch Airway"]
    F -->|"Conscious & Breathing"| I["Sit Upright at 45 to 90 Degrees, Loosen Collar, Keep Completely Still, Give Nothing to Drink"]
    I --> J{"Check for Thermal Airway Burn Red Flags: Hoarse Voice, Soot in Mouth, or Stridor?"}
    J -->|"Yes: Impending Airway Closure"| K["Alert Dispatch That Airway Is Swelling Shut (ALS Intubation Priority) & Keep Sitting Upright"]
    J -->|"No"| L["Keep Warm With Blankets and Transport to Emergency Department for CO-Oximetry & 48h Lung Check"]
    G --> L
    H --> L
    K --> L

The 3 simultaneous injury mechanisms of smoke inhalation¶

Why can a person walk out of a house fire without a single burn mark on their skin and still suffer life-threatening respiratory failure an hour later? Because indoor fire smoke attacks the human body through three separate mechanisms at the same time:

Recognizing upper airway thermal burns before the throat swells shut¶

Dry heated air is actually a poor conductor of heat, so when someone inhales hot dry smoke, the wet mucous membranes of the nose, mouth, and throat absorb almost 100 percent of the thermal energy before the air passes below the vocal cords (with one major exception: live steam, which carries 4,000 times the heat capacity of dry air and scalds all the way down into the deep lung bronchioles).

Because the upper throat absorbs all that heat, the tissues around the epiglottis and vocal cords blister and swell with fluid (edema) rapidly, just like a blister rising on a burned hand. In an adult, the narrowest part of the windpipe at the vocal cords (glottic opening) is only a few millimeters wide (and in a child, the size of their little finger). Once swelling reduces that airway diameter by half, breathing resistance increases 16-fold (by Poiseuille's fourth-power law).

Check every fire survivor immediately for the "5 Airway Burn Red Flags"¶

1. Singed nasal hairs or burns around the lips, nose, beard, or eyebrows.
2. Carbonaceous sputum: Black soot coating the tongue, teeth, or back of the throat, or spitting up gray/black-flecked saliva.
3. Hoarseness or voice change: Ask the person to say their name and take a breath. If their voice sounds raspy, squeaky, muffled ("hot-potato voice"), or drops to a whisper, swelling has already started on the vocal cords.
4. Difficulty swallowing saliva (dysphagia) or drooling.
5. Inspiratory Stridor: A harsh, high-pitched crowing, whistling, or gasping sound heard without a stethoscope when the person breathes in. Stridor is an extreme medical emergency, it means the windpipe is already 70 to 80 percent swollen shut and may close completely within minutes.

First-aid action for suspected airway burns:

• Keep the person sitting bolt upright (45 to 90 degrees), never lay them flat on their back, because lying flat increases venous blood pooling in the neck and speeds up throat swelling.
• Give zero water, ice, or food by mouth (wipe dry lips with a wet cloth only).
• Call 911 / 999 / 112 back immediately if stridor or hoarseness starts developing so an Advanced Life Support (ALS) paramedic crew can intubate early before the airway seals.

Carbon Monoxide (CO) and Hydrogen Cyanide (HCN): "The Toxic Twins"¶

While structure fire smoke contains both carbon monoxide and hydrogen cyanide, pure carbon monoxide poisoning also happens every day without any fire or smoke at all, from portable gasoline generators run in garages or near windows, blocked furnace flues, gas water heaters with backdrafting vents, indoor charcoal grills or propane heaters, and cars idling inside attached garages.

Why Carbon Monoxide + Hydrogen Cyanide are so lethal together¶

1. Carbon Monoxide (\(\text{CO}\)) triple blow:
   • First, \(\text{CO}\) binds to the iron atoms in red-blood-cell hemoglobin 200 to 250 times more tightly than oxygen, forming carboxyhemoglobin (\(\text{COHb}\)) so red blood cells cannot pick up oxygen in the lungs.
   • Second, once one \(\text{CO}\) molecule binds to a hemoglobin protein, it alters the structural shape of the other three oxygen-binding sites (the Haldane Effect / leftward shift of the oxyhemoglobin dissociation curve), preventing the blood from letting go of the oxygen it does have into starving brain and heart tissues.
   • Third, \(\text{CO}\) binds to cardiac myoglobin inside the heart muscle itself, directly depressing heart pumping strength and triggering dangerous arrhythmias.
2. Hydrogen Cyanide (\(\text{HCN}\)) cellular lockout:
   • Whenever a modern couch, polyurethane foam mattress, carpet, or plastic appliance smolders in a house fire, it releases hydrogen cyanide gas.
   • Inhaled cyanide enters the bloodstream and binds to the ferric iron (\(\text{Fe}^{3+}\)) in cytochrome c oxidase inside every cell's mitochondria, shutting down aerobic cellular respiration in seconds. Even if oxygen is present in the blood, the cells cannot use it, forcing the body into fatal anaerobic lactic acidosis and sudden collapse.

Symptoms of Carbon Monoxide poisoning by blood COHb level¶

How 100% Medical Oxygen and Hyperbaric Oxygen save the brain¶

Why can a carbon monoxide or smoke inhalation victim not simply "sit outside on the porch in fresh air for half an hour and go back to bed" instead of riding in the ambulance?

Look at the physics of how long it takes to wash carbon monoxide off poisoned hemoglobin (the \(\text{COHb}\) Elimination Half-Life):

• Breathing ordinary outdoor room air (\(21\%\text{ Oxygen}\) at 1 atmosphere): The half-life of carboxyhemoglobin is 4 to 6 hours (meaning if your blood level is 40 percent, after 5 hours sitting on the porch it is still at a toxic 20 percent, continuing to cause brain lipid peroxidation and heart damage all night).
• Breathing \(100\%\text{ High-Flow Medical Oxygen}\) through a tight paramedic Non-Rebreather Mask (\(15\text{ L/min}\)): Cuts the half-life by four-fold down to 60 to 90 minutes.
• Inside a Hospital Hyperbaric Oxygen Therapy (\(\text{HBOT}\)) Chamber (\(100\%\text{ Oxygen}\) at \(2.5\text{ to }3.0\text{ Atmospheres}\) of pressure): Cuts the half-life down to just 20 to 30 minutes, dissolves enough pure oxygen directly into the liquid blood plasma to keep the brain and heart alive without even needing red blood cells, and blocks white blood cells from attacking brain myelin (preventing Delayed Neurological Sequelae / DNS, a devastating syndrome of memory loss, Parkinson-like tremors, and personality changes that can strike 2 to 40 days after untreated CO poisoning).

Hospital antidote for fire-smoke Cyanide poisoning (Hydroxocobalamin)¶

When paramedics or emergency physicians treat a victim pulled unconscious from indoor structure smoke (who has soot in the mouth, confusion/coma, or high blood lactate), they administer an intravenous antidote called Hydroxocobalamin (Cyanokit), a concentrated precursor of Vitamin B12a. Hydroxocobalamin binds directly to toxic cyanide ions inside the bloodstream to form completely harmless cyanocobalamin (regular Vitamin B12), which is safely excreted in the urine (turning the patient's urine and skin temporarily harmless pinkish-red for a few days).

Treating companion eye, skin, and clothing contamination¶

When someone escapes a smoky fire:

1. Flush smoke-irritated eyes with clean water or saline: Acid gases and soot particles trapped under the eyelids cause severe chemical conjunctivitis and corneal burns. Once breathing is stable, gently rinse stinging eyes with clean lukewarm tap water, bottled drinking water, or sterile saline eyewash for 10 to 15 minutes from the inner corner (near the nose) outward, and remove contact lenses as soon as possible.
2. Cool any skin burns and remove soot-soaked outer clothing: If clothing is hot or smoldering, douse with cool clean water for 20 minutes (never use ice or butter on burns; see our burns and scalds first aid guide). Once out of danger, remove heavy outer jackets or sweaters saturated with toxic plastic soot so the person stops inhaling off-gassing chemicals from their own collar, and wrap them in a clean dry blanket to prevent hypothermia.

The 24-to-48-Hour Delayed Lung Edema Watch¶

Even if an emergency physician clears a mild smoke-exposure patient to go home after a few hours of oxygen observation, toxic chemical gases like phosgene and hydrochloric acid have a latent "time-bomb" period of 12 to 48 hours before deep lung inflammation peaks.

Monitor the person closely for the next 2 full days (and over the next 4 weeks for carbon monoxide neurological changes). Return to the Emergency Department immediately if any of these warning signs appear:

• New or worsening shortness of breath at rest or when walking across a room.
• Inability to lie flat in bed (orthopnea) without feeling like they are suffocating or coughing.
• Wheezing, chest tightness, or wet crackling/bubbling sounds when breathing.
• Coughing up pink, frothy, or blood-streaked mucus (classic sign of delayed pulmonary edema fluid leaking into the air sacs).
• Fever, chills, or thick yellow-green sputum (secondary bacterial pneumonia after smoke damage to airway cilia).
• New headaches, memory lapses, confusion, dizziness, irritability, or unsteady balance days or weeks after carbon monoxide exposure. For preventing future leaks and fires, review our carbon monoxide leaks and alarms and house fire escape and survival guides.

Frequently asked questions¶

Sources checked¶

• American Heart Association (AHA, United States) and American Red Cross (United States): Guidelines for First Aid and Cardiopulmonary Resuscitation , Smoke Inhalation, Carbon Monoxide / Cyanide Asphyxial Arrest, and Oxygen Administration.
• National Health Service (NHS, United Kingdom), St John Ambulance (United Kingdom), and UK Health Security Agency (UKHSA, United Kingdom): Smoke Inhalation and Carbon Monoxide Poisoning First Aid, Delayed Pulmonary Edema Red Flags, and Hyperbaric Referral Criteria.
• Centers for Disease Control and Prevention (CDC, United States) and Agency for Toxic Substances and Disease Registry (ATSDR, United States): Clinical Guidance on Carbon Monoxide (\(\text{CO}\)) Poisoning, Pulse Oximetry Limitations, Pregnancy Fetal Risk, and Hydrogen Cyanide (\(\text{HCN}\)) Co-Toxicity in Fire Smoke.
• American Burn Association (ABA, United States) and British Burn Association (United Kingdom): Advanced Burn Life Support (ABLS) , Inhalation Injury Triage, Supraglottic Thermal Edema, and Early Intubation Indications.
• Undersea and Hyperbaric Medical Society (UHMS, International / United States) and European Committee for Hyperbaric Medicine (ECHM, European Union): Indications for Hyperbaric Oxygen Therapy (\(\text{HBOT}\)) in Acute Carbon Monoxide Poisoning and Prevention of Delayed Neurological Sequelae.

Related guides¶

• Burns and scalds first aid
• CPR and AED step-by-step guide
• Carbon monoxide leaks and alarms
• House fire escape and survival
• Emergency numbers by country