Carbon Dioxide (CO2)
Carbon Dioxide is a natural component of air at approximately 0.03%. It is also a key component of Black Damp,
caused by biological oxidation such as rotting mine timbers. Increased concentrations of carbon dioxide
replace the oxygen content of the mine air thus producing a toxic atmosphere.
Specific Gravity: 1.529
Properties:
- Colorless
- Odorless
- Heavier than air
- Acidic taste at high concentrations
Health Effects:
- At 5%, stimulated respiration.
- At 7% to 10%, unconsciousness after a few minutes of exposure.
Limits:
- Ceiling – 1.5%
- IDLH – 50,000 PPM
Additional Resources
Carbon Monoxide (CO)
Carbon monoxide results from incomplete combustion of organic carbon-based
materials. It is also an after-product
of detonated explosives and diesel engines. Carbon monoxide is highly toxic to the body. When
inhaled, CO quickly bonds with the body’s hemoglobin, thus
reducing the blood’s ability to carry oxygen throughout the body.
Specific Gravity: 0.967
Properties:
- Flammable
- Colorless
- Tasteless
- Odorless
- Lighter than air
Health Effects:
| CONCENTRATION (PPM) |
PHYSIOLOGICAL EFFECT |
| 200 |
Slight headache, tiredness, dizziness, nausea after 2 to 3 hrs. |
| 400 |
Frontal headache within 1 to 2 hrs., life threatening after 3 hrs. |
| 800 |
Dizziness, nausea and convulsions within 45 minutes. Unconsciousness within 2 hours. Death in 2 to 3 hours. |
| 1,600 |
Headache, dizziness, nausea within 20 minutes. Death within 1 hour. |
| 3,200 |
Headache, dizziness, and nausea within 5 to 10 minutes. Death within 30 minutes. |
| 6,400 |
Headache, dizziness, and nausea within 1 to 2 minutes. Death within 10 to 15 minutes. |
Limits:
- TLV – 50 PPM
- Ceiling – 200 PPM
- IDLH – 1500 PPM
Explosive Range:
Additional Resources
Hydrogen (H2)
Hydrogen is an extremely explosive gas that is commonly found in battery charging
stations. It can also be created when
water is applied to super hot mine fires or from the incomplete combustion in
explosions. Adding strong acids to iron
or steel can also release hydrogen into the atmosphere.
Specific Gravity: 0.0695
Properties:
- Colorless
- Odorless
- Tasteless
- Flammable
- Explosive when exposed to heat or flame
- Lighter than air
- Needs 5% Oxygen to ignite
Health Effects:
- Asphyxiant at high concentrations
Limits:
Explosive Range:
- 4.1% to 74%
- Violent explosions when concentrations are over 7% to 8%
Additional Resources
Hydrogen Sulfide (H2S)
Hydrogen sulfide is an extremely toxic gas. It blocks the use of oxygen by the body’s cells. It is produced when sulfur compounds decompose. It is commonly associated with acid mine
water. This gas is released whenever a mine pool is agitated. Can be produced in mine fires should sulfide ores be present.
Specific Gravity: 1.191
Properties:
- Colorless
- Odor similar to rotten eggs at very low concentrations (0.003 PPM)
- Extremely flammable
- Heavier than air
- Highly soluble
Health Effects:
| CONCENTRATION (PPM) |
PHYSIOLOGICAL EFFECT |
| 10 |
Obvious and unpleasant odor (rotten eggs). |
| 50 |
Mild conjunctivitis, respiratory tract irritation in 30 to 60 minutes. |
| 100 |
Kills sense of smell in 3 to 5 minutes, may sting eyes and throat. |
| 200 |
Stings eyes and throat. |
| 250 |
Exposure for 1 hour is the Hazardous Limit concentration which may cause death. |
| 300 |
Immediately dangerous to life. |
| 500 |
Dizziness, coughing, breathing ceases within minutes, artificial respiration required. |
| 600 |
May cause death within 2 minutes. |
| 700 |
Unconscious quickly, death if not rescued immediately. |
| 1000 |
Unconscious instantly, breathing ceased, death within a few breaths. Death may occur even if rescued immediately. |
Limits:
- TLV – 10 PPM
- Ceiling – 15 PPM
- IDLH – 300 PPM
Explosive Range:
Ignition Temperature:
Additional Resources
Oxygen (O2)
Oxygen is essential to support life. Although oxygen is not an explosive gas, it does support and accelerate combustion. Normal air contains 20.94% oxygen by
volume. Atmospheres containing less than this amount are known as oxygen deficient.
Specific Gravity: 1.105
Properties:
- Colorless
- Odorless
- Tasteless
- Non-Explosive
- Supports Combustion
- Heavier than air
- Easily displaced by other gases introduced into the atmosphere
Health Effects:
| CONCENTRATION (%) |
PHYSIOLOGICAL EFFECT |
| 21% |
Breathing easiest |
| 19.5% |
Minimum required by law. |
| 17% |
Breathing faster and deeper, possible impaired judgement. |
| 16% |
First signs of anoxia or hypoxia occur. |
| 15% |
Dizziness, buzzing in ears, headache, blurred vision, rapid breathing. |
| 12% to 16% |
Rapid breathing and pulse, impaired muscular coordination. |
| 10% to 12% |
Emotional upset and abnormal fatigue on exertion. |
| 6% to 10% |
Nausea and vomiting, inability to move, unconsciousness. |
| < 6% |
Convulsive movements, gasping respiration, breathing ceases, cardiac arrest occurs. |
Additional Resources
Methane (CH4)
Methane gas is found naturally in most coal seams. It includes many volatile organic compounds including methane, ethane,
butane, propane, and contaminants. Methane is the most common ingredient (>50%) found in natural
gas. It is the most common dangerous
gas found in underground coal mines.
Specific Gravity: 0.5545
Properties:
- Colorless
- Odorless
- Tasteless
- Flammable
- Lighter than air
- Largest component of Fire Damp (70% to 98%)
Health Effects:
- Asphyxiation in high concentrations due to displacement of oxygen
- Dizziness, headache, and nausea in high concentrations
Explosive Range:
- 5% to 15% with a minimum of 12.5% O2
Ignition Temperature:
Additional Resources
Nitrogen (N2)
Nitrogen composes 78.09% of the atmosphere. It is a non-flammable gas.
Specific Gravity: 0.967
Properties:
- Colorless
- Odorless
- Tasteless
- Non-flammable
- Lighter than air
Health Effects:
Limits:
Additional Resources
Nitrogen Dioxide (NO2)
Nitrogen dioxide is an extremely toxic gas to the human body. It is produced from the detonation of explosives and it is found
in diesel exhaust. It is a non-flammable gas that is heavier than air. In high concentrations, nitrogen dioxide
forms nitric acid in the lungs causing pulmonary edema.
Specific Gravity: 1.5894
Properties:
- Reddish-brown color in high concentrations
- Acrid or “bleach” odor
- Non-flammable
- Heavier than air
Health Effects:
| CONCENTRATION (PPM) |
PHYSIOLOGICAL EFFECT |
| 1 to 13 |
Irritation of nose and throat. |
| 10 to 20 |
Mild irritation of eyes, nose and upper respiratory tract. |
| 80 |
Tightness in chest after 3 to 5 minutes. |
| 90 |
Pulmonary edema after 30 minutes. |
Limits:
- TLV – 1 PPM
- Ceiling – 3 PPM
- IDLH – 50 PPM
Additional Resources
Sulfur Dioxide (SO2)
Sulfur dioxide is produced when iron pyrite burns in gob fires or by blasting sulfide
ores. It is also found in diesel exhaust. Sulfur dioxide has the same
effect on the body as nitrogen dioxide, except that sulfuric acid is created in
the lungs. It is a non-flammable gas.
Specific Gravity: 2.264
Properties:
- Colorless
- Heavy sulfur odor
- Acidic taste
- Heavier than air
- Non-flammable
Health Effects:
| CONCENTRATION (PPM) |
PHYSIOLOGICAL EFFECT |
| 0.3 to 1 |
Detectable by taste rather than odor. |
| 3 to 5 |
Detectable odor. |
| 10 |
Maximum concentration allowable for prolonged exposure. |
| 20 |
Least amount causing coughing and irritation of eyes. |
| 50 |
Irritation to eyes, lungs, throat. |
| 50 to 100 |
Maximum concentration for short exposure (30 to 60 minutes). |
| 150 |
May be endured for several minutes. Extremely disagreeable. |
| 400 to 500 |
Life threatening. |
Limits:
- TLV – 5 PPM
- Ceiling – 10 PPM
- IDLH – 100 PPM
Additional Resources
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