Carbon Dioxide Health Hazard Information Sheet
CO2 is considered to be minimally toxic by inhalation. The primary health effects caused by CO2 are the result of its behavior as a simple asphyxiant. A simple asphyxiant is a gas which reduces or displaces the normal oxygen in breathing air.
Symptoms of mild CO2 exposure may include headache and drowsiness. At higher levels, rapid breathing, confusion, increased cardiac output, elevated blood pressure and increased arrhythmias may occur.
“On 21 August 1986, a limnic eruption at Lake Nyos in northwestern Cameroon killed 1,746 people and 3,500 livestock.[1]
The eruption triggered the sudden release of about 100,000–300,000 tons (1.6 million tons, according to some sources) of carbon dioxide (CO2).[2][3] The gas cloud initially rose at nearly 100 kilometres per hour (62 mph; 28 m/s) and then, being heavier than air, descended onto nearby villages, displacing all the air and suffocating people and livestock within 25 kilometres (16 mi) of the lake.[4][5]”
“https://en.wikipedia.org/wiki/Lake_Nyos_disaster“
Your experience with local CO2 pipeline ruptures may vary.
CO2 is a byproduct of ventilation. The lungs (alveoli) have a strong affinity for Carbon Dioxide, much greater than the attraction of O2. It is not exactly the inhalation of CO2 that is the problem but rather the inability to get it out of your system as part of regular metabolism. This is referred to as ‘ventilation.’
The amount of CO2 in the atmosphere is practically that of a ‘trace gas.’ Close to 99% of the atmosphere is Oxygen and Nitrogen. If a person is unable to eliminate CO2 from their system, this is a life threatening emergency.