How Do I ...
Online Services
Public Records
Carbon Monoxide
Facts about CO
Symptoms and Effects
CO Alarms
Safety Videos

Symptoms and Effects of Carbon Monoxide

Woman holding her headRecognizing early warning signs of CO poisoning is sometimes difficult because early symptoms of CO exposure (headache, dizziness, nausea) are nonspecific and may be mistaken for symptoms of other illnesses such as colds, flu or food poisoning.

Did you know?

The severity of symptoms of CO exposure is influenced by three main factors:

  • the concentration of CO in the environment,
  • how long the exposure lasts, and
  • work load and breathing rate.

Generally, symptoms are similar to the flu without a fever.

Common Mild Exposure Symptoms

  • Slight headache
  • Nausea
  • Vomiting
  • Fatigue (flu-like symptoms)

Common Medium Exposure Symptoms

  • Drowsiness
  • Confusion
  • Fast heart rate
  • Throbbing headache

Common Extreme Exposure Symptoms

  • Convulsions
  • Unconsciousness
  • Heart and lung failure
  • Brain damage
  • Death


Health Effects of Carbon Monoxide

 Concentration (PPM) Concentration (%) Exposure time and symptoms
 9  0.0009 Maximum allowed ambient by EPA
 35  0.0035 Maximum for 8 hour exposure
 200  0.02 Headache in 2 to 3 hours
 400  0.04 Life threatening after 3 hours
 800  0.08 Dizziness, nausea, convulsion in 45 minutes
 1600  0.16 Headache, dizziness, nausea in 20 minutes
 3200  0.32 Headache, dizziness, nausea in 10 minutes 
 6400  0.64  Headache, dizziness, nausea in 2 minutes
12800 1.28 Death in 1 to 3 minutes

Learn more facts about carbon monoxide and how you can protect yourself from CO poisoning.

Printed from: