Carbon Monoxide Poisoning

Effect of CO on Mice (left side) and Canaries (right side):

% CO (ppm)
% CO (ppm)
0.16 (1600) Very slight distress at end of hour0.09 (900) Very slight distress at end of hour
0.20 (2000) Distress in 8 minutes; partial collapse in 15 minutes 0.12 (1200) Weaker at end of hour than after exposure to 0.9% CO
0.31 (3100) Distress in 4 minutes; collapse in 7.5 minutes; lost muscular power in 35 minutes 0.15 (1500) Distress in 3 minutes; fell from perch in 18 minutes
0.46 (4600) Distress in 2 minutes; collapse in 4 minutes. 0.20 (2000) Distress in 1.5 minutes; fell from perch in 5 minutes
0.57 (5700) Distress in 1 minute; collapse in 2 minutes; muscular power lost in 7 minutes; death in 16 minutes. 0.29 (2900) Fell from perch in 2.5 minutes
0.77 (7700) Distress in 1 minute; muscular power lost in 6.5 minutes; death in 12.5 minutes. . .


  • Canaries are better suited than mice as indicators of the presence of carbon monoxide in the air, as they more quickly show signs of distress.
  • The symptoms of CO poisoning in birds are more clearly defined, ie. birds sway noticeably on their perch before falling and its fall is a better indication of danger than is the squatting, extended posture that mice assume without much struggling, attempts to walk, or other preliminary symptom of poisoning.
  • Canaries give a more timely warning of CO, and the symptoms exhibited are more easily noticed.

    Human - Canary Study:

  • An atmosphere of 0.25% CO (2500 ppm) was created in a chamber having a volume of 80 cu. ft. Mr. Burrell entered this chamber taking with him canaries and pigeons. He states that "the canaries showed distress in 1 minute, and fell from their perches in 3 minutes. The pigeons showed only slight distress in 11 minutes. The author remained in the atmosphere for 20 minutes; he then had a slight headache, but later was ill 10 hours and suffered nausea and severe headache. Remaining in the atmosphere for 20 minutes more would have caused complete collapse and serious after-effects."


  • "The experiment showed that small birds are much more susceptible to the action of CO than are men, and demonstrates the desirability of using small birds, such as canaries, rather than larger ones, such as pigeons."

    From: Burrell, Geo. A. (1912) The use of mice and birds for detecting carbon monoxide after mine fires and explosions. Technical Paper 11, Department of the Interior, Bureau of Mines.

    ...... last changed 07/04/01

    Properties of CO, 1912

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