Another natural gas explosion is being reported as the possible fuel for a massive fire ball which has destroyed several homes and critically injured at least 6 people in San Bruno, CA http://www.ktvu.com/news/24948907/detail.html
Natural gas explosions can be deadly and cause catastrophic injuries. Fortunately, they don't happen frequently, but when they do, the results are often devastating. The affected homes along the distribution lines can be blown off their foundations. Wide spread fire, serious injury and death can result. It is possible that at times entire blocks of homes in neighborhoods are involved.
The cause of the natural gas explosion can be leaking gas from a distribution line in neighborhoods or from appliance or gas lines in or around the home. Many times, the occupants of the home never smell the gas prior to the explosion. The reason for this is that the odor typically associated with natural gas is actually added to the gas by the gas provider. The odors are usually called mercaptans and when gas escapes, the odor can be "scrubbed" out of the gas so that when the gas is pooling prior to exploding, the gas is odorless. Natural gas can also experience "odor fade" where the mercaptans are reduced leaving the gas odorless. The amount of escaping gas determines the amount of devastation of the fire and explosion.
To the untrained eye, the explosion may seem "unexplainable" or even "suspicious." In reality, finding the source of the leak and source of ignition explains the devastating nature of this event. Many times the neighbors or occupants of the home are killed or injured to the point where obtaining interviews of the occupants is impossible. The evidence of the source of the leak may exist in the debris, or may exist underground or elsewhere. It is important to secure experienced representation in these matters so that blame for the blast is not wrongly cast.