A gas explosion is the ignition of a mixture of air and flammable gas, typically from a gas leak. In household accidents, the principal explosive gases are those used for heating or cooking purposes such as natural gas, methane, propane, butane. In industrial explosions, many other gases, like hydrogen, as well as evaporated (gaseous) gasoline or ethanol play an important role. Industrial gas explosions can be prevented with the use of intrinsic safety barriers to prevent ignition, or use of alternative energy.
Lower and upper explosive limits
Whether a mixture of air and gas is combustible depends on the air-to-fuel ratio. For each fuel, ignition occurs only within a certain range of concentration, known as the upper and lower flammability limits. For example, for methane and gasoline vapor, this range is 5-15% and 1.4-7.6% gas to air, respectively. An explosion can only occur when fuel concentration is within these limits.
Australian federal MP George Edwards and a gas mechanic were killed on February 4, 1911, when a gasometer exploded on Edwards' property in Turramurra, New South Wales.
The Pittsburgh gasometer explosion occurred during the morning of November 14, 1927, in the north side of Pittsburgh. A large gasometer exploded, killing 28 people and injuring hundreds.
The Mather Mine disaster occurred on May 19, 1928, in Mather, Pennsylvania. A methane gas and dust explosion resulted in the deaths of 195 men.
The New London School explosion occurred on March 18, 1937, when a natural gas leak caused an explosion, destroying the New London School of the city of New London, Texas. The disaster killed three hundred students and teachers.
On January 27, 1943, 43 people in the Sydney suburb of Chippendale inhaled fumes after a chlorine cylinder leaked.
The Cleveland East Ohio Gas Explosion occurred on the afternoon of Friday, October 20, 1944. The resulting gas leak, explosion and fires killed 130 people and destroyed a one-square-mile area on Cleveland, Ohio’s east side.
On October 31, 1963, the Indiana State Fairgrounds Coliseum gas explosion (later known as the Indiana Farmers Coliseum) occurred during the opening night for the Holiday on Ice show, killing 81 and injuring nearly 400. The cause was an explosion following a propane tank leak.
On March 1, 1965, the LaSalle Heights Disaster occurred when a gas line fractured in a low-cost residential neighborhood near Montreal, Quebec, killing 28 people and injuring dozens.
On January 9, 1968, in Reading, Pennsylvania, an explosion killed nine people and demolished two houses. A gas company spokesman said Reading workmen digging in the street to repair a water main had hit a gas line shortly before the explosion.
On Saturday, April 6, 1968, the Richmond, Indiana explosion occurred in the middle of downtown Richmond, Indiana. There were two explosions; the first was caused by a natural gas leak, while the second by gunpowder and ammunition inside a sporting goods store. 41 people were killed and more than 150 injured, and four squares of downtown Richmond, Indiana, were heavily damaged by the explosion or subsequent fire.
Ronan Point was a 23-story council tower block in Newham, east London. On May 16, 1968, a gas explosion caused the collapse of a whole corner of the building. Four people were killed in the collapse.
On April 8, 1970, a gas explosion during construction at the Osaka Metro's Tenjimbashisuji Rokuchōme Station in Kita-ku, Osaka, Japan killed 79 people, injured 420 others, and damaged and destroyed 495 buildings.
On October 21, 1971, Clarkston explosion on October 21, 1971; a build-up of gas under a shopping centre left 22 dead and around 100 injured.
October 23, 1980, a propane explosion at Escuela Nacional de Marcelino Ugalde (Marcelino Ugalde Primary School), Ortuella, Vizcaya, Spain. According to the local government's official report, 50 schoolchildren and 3 adults were killed and an additional 128 people injured.
January 23, 1983, two people died in a gas explosion which destroyed the Golden Crown restaurant, Bye Street, Ledbury, England.