Inhaling toxic fumes, carbon monoxide, or chlorine gas, leading to chemical suffocation and cellular hypoxia.
Step-by-Step Guidance
Carry or lead the patient out of the gas-filled environment into open air immediately.

Call EMS. Inhaled toxins require high-flow oxygen therapy in a hospital.

Loosen shirts, buttons, or jackets around the neck and chest to make breathing easier.

If they are not breathing or gasping, start CPR chest compressions and rescue breathing.

Keep the patient warm and sitting upright if possible, to maximize lung expansion.

Days to weeks (risk of neurological injury)
Timeline is typical for uncomplicated healing. Always follow doctor guidance.