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.

Properties:

·       Colorless

·       Odorless

·       Heavier than air

·       Acidic Taste at high concentrations

Health Effects:

·       At 5%, stimulated respiration

·       At 7% to 10%, unconsciousness after few minutes of exposure

Limits:

·       Ceiling – 1.5%

·       IDLH – 50,000 PPM

            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.

Properties:

·       Flammable

·       Colorless

·       Tasteless

·       Odorless

·       Lighter than air

Health Effects:

Limits:

·       TLV – 50 PPM

·       Ceiling – 200 PPM

·       IDLH – 1500 PPM

Explosive Range:

·       12.5% to 74%

            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.

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:

·       None established

Explosive Range:

·       4.1% to 74%

·       Violent explosions when concentrations are over 7% to 8%

            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.

Properties:

·       Colorless

·       Odor similar to rotten eggs at very low concentrations (0.003 PPM)

·       Extremely flammable

·       Heavier than air

·       Highly soluable

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:

·       4.3% to 46%

Ignition Temperature:

·       700° F

            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.

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

            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.

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:

·       1100° F to 1300° F

            Nitrogen composes 78.09% of the atmosphere.  It is a non-flammable gas.

Properties:

·       Colorless

·       Odorless

·       Tasteless

·       Non-flammable

·       Lighter than air

Health Effects:

·       Unknown

Limits:

·       Ceiling – 81,000 PPM

            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.

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

            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.

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