Safety Natural Gas (Methane): To effectively deal with a potential problem,  you should have a basic understanding of the reactions that can be expected with natural gas (methane) under given situations. Natural gas (methane) is neither toxic nor poisonous.  Tests show that concentrations of 25% gas mixed with air produce no ill effects.  However, if this gas displaces the air in an enclosed space, suffocation can occur because of the lack of oxygen. When natural gas (methane) is released in a confined space, the highest concentration will be at the highest level and air will be displaced from the top downward. Most natural gas (methane) is odorless in its natural state; it is also in a vapor form therefore it is almost impossible to detect without some type of gas detection equipment. The ignition point of natural gas (methane) is in the range of 900 –1200 ºF, this temperature is reached by pilot lights, flint sparks, matches or sparks from electrical switches or motors.  The explosive range of natural gas (methane) is 5% -15%. Natural gas (methane) is lighter than air (specific gravity = 1), it will rise and diffuse rapidly when it escapes to an open area.  The Specific Gravity of natural gas (methane) is in the range of 0.56.  Lighter than air natural gas (methane) should not be confused with liquefied petroleum gas.  This gas is more commonly called L.P., bottle gas, propane, butane, and various other trade names.  Liquefied petroleum gases are all heavier than air and will collect in low places when not confined.