Gas Risks
How the human body reacts to oxygen deficiency
Effects of carbon monoxide (CO) on the human body
| Concentration (ppm) | Effects and Toxicity |
| 100 | No noticeable effects even after breathing for a few hours |
| 200 | A slight headache in about 1.5 hours. |
| 400～500 | Headache, nausea and ringing in the ears within about 1 hour. |
| 600～1000 | Loss of consciousness in about 1 to 1.5 hours. |
| 1500～2000 | Disabling headache, dizziness and nausea within about 0.5 to 1 hour and loss of consciousness. |
| 3000～6000 | Headache, dizziness, disabling nausea…etc. within minutes. Exposure for 10 to 30 minutes can result in death. |
| 10000 | Causes immediate loss of consciousness and death. |
Properties and hazards of combustible gases (iso-butane: i-C4H10)
| Main properties | Clear compressed liquid with a distinctive odor
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Effects of hydrogen sulfide (H2S) on the human body
| Concentration (ppm) | Effects and Toxicity |
| 0.025 | Vague odor (this varies from individual to individual.) |
| 0.3 | Clear odor |
| 3～5 | Smell a moderate degree of unpleasant odor. |
| 10 | First level of irritation of the mucous membranes of the eyes. |
| 20～40 | A strong odor. First level of irritation of the mucous membranes of the lungs. |
| 100 | The sense of smell is impaired within 2 to 15 minutes. The eyes and respiratory tract are irritated within 1 hour. Continuous exposure for 8 to 48 hours can result in death. |
| 170～300 | One hour of exposure is the limit to not cause serious health problems. |
| 400～700 | Potentially fatal exposure in 0.5~1 hour. |
| 800～900 | Causes loss of consciousness, respiratory arrest and death. |
| 1000 | Causes immediate loss of consciousness and death. |
Properties and dangers of combustible gases (methane: CH4)
| Main properties | Transparent, no gas odor.
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