poison: a substance with an inherent property that tends to destroy life or impair health.
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Carbon dioxide (CO2) is a
toxic gas at high concentration, as well as an
asphyxiant gas (due to reduction in oxygen). Irritation of the eyes, nose and throat occurs only at high concentrations. The concentration thresholds for health effects are outlined in the table.
Exposure limits
(% in air) - - - - - -Health Effects
2-3 - - - - - Unnoticed at rest, but on exertion there may be marked shortness of breath
3 - - - - - Breathing becomes noticeably deeper and more frequent at rest
3-5 - - - - - Breathing rhythm accelerates. Repeated exposure provokes headaches
5 - - - - - Breathing becomes extremely laboured, headaches, sweating and bounding pulse
7.5 - - - - - Rapid breathing, increased heart rate, headaches, sweating, dizziness, shortness of breath, muscular weakness, loss of mental abilities, drowsiness, and ringing in the ears
8-15 - - - - Headache, vertigo, vomiting, loss of consciousness and possibly death if the patient is not immediately given oxygen
10 - - - - - Respiratory distress develops rapidly with loss of consciousness in 10-15 minutes
15 - - - - - Lethal concentration, exposure to levels above this are intolerable
25+ - - - - - Convulsions occur and rapid loss of consciousness ensues after a few breaths. Death will occur if level is maintained.
Carbon Dioxide (CO2)