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• Small amounts of water leaking from the base of the chimney, vent or flue pipe.
• Rust on the portion of the vent pipe visible from outside your home.
• The absence of a draft in your chimney (indicating blockage).
• Fallen soot from the fireplace chimney.
• Loose, damaged or discolored bricks on your chimney.
Clues You Cannot See...
• Internal appliance damage or malfunctioning components
• Improper burner adjustment
• Hidden blockage or damage in chimneys
The maximum allowable concentration for
continuous exposure for healthy adults in any
8-hour period, according to OSHA*.
Slight headache, fatigue, dizziness, nausea
after 2-3 hours.
Frontal headaches within 1-2 hours, life
threatening after 3 hours.
Dizziness, nausea and convulsions within 45
minutes. Unconsciousness within 2 hours. Death
within 2-3 hours.
Headache, dizziness and nausea within 20
minutes. Death within 1 hour.
Headache, dizziness and nausea within 5-10
minutes. Death within 25-30 minutes.
Headache, dizziness and nausea within 1-2
minutes. Death within 10-15 minutes.
Death within 1-3 minutes.
50 ppm
200 ppm
400 ppm
800 ppm
1,600 ppm
3,200 ppm
6,400 ppm
12,800 ppm
Reminder:
This chart relates to the exposure of healthy adults.
Concentration
of CO in the Air
(ppm = parts per million)
Approximate Inhalation Time and Symptoms Developed
Understand the Effects of Carbon Monoxide Exposure:
* Occupational Safety and Health Administration
Carbon Monoxide Safety
