Fire inspectors and rescue workers search through the rubble after the East Ohio Gas Company explosion and fire. Credit: Cleveland Public LibraryThe East Ohio Gas explosion took place on Friday, 20 Oct. 1944, when a tank containing liquid natural gas equivalent to 90 million cubic feet exploded, setting off the most disastrous fire in Cleveland's history. The explosion and fire destroyed 1 square mile of the city of Cleveland, Ohio, and killed 131 people, including 55 East Ohio employees.

There were four tanks at the east Ohio Gas Company. The first three were spherical type tanks which had a band around the middle that carried the weight of the tank and its contents. Tank No. 4, the one that failed, was built in 1942 to provide additional reserve gas for local war industries and was a new self-supporting type of tank. The new tank was built with low nickel content (3.5%) because stainless steel alloys were scarce due to World War II.

On October 20, 1944, the tanks had been filled to capacity in readiness for the coming winter months. At about 2:15PM, normal mechanical stress on the Tank #4 walls created a leak, which lead to failure of the outer carbon steel shell, causing the LNG tank to completely fail and releasing all of its contents into the nearby streets and sewers of Cleveland.

The LNG vaporized quickly and formed a flammable gas cloud. The liquid LNG flowed into the gutters and then into the storm sewers. Many of the homes had their windows and doors open because it was a warm afternoon, so the gas flowed more easily. At some point the vapor cloud hit an ignition source and ignited. The gas inside the homes and the storm sewer ignited explosively, blowing manhole covers off and spreading the fire. The ball of flame could be seen at John Adams High School, seven miles away. The explosion of a second LNG tank trapped some residents who had returned to their homes after the first explosin, thinking it was safe.  Some of the victims were so badly burned they would never be identified.

According to a U.S. Bureau of Mines report, the Cleveland disaster destroyed 79 homes, 2 factories, 217 cars, and 7 trailers. Nearly 700 people were left homeless and over 130 were injured. The death toll reached 120, but could have been higher if the accident had occurred later in the day, after students and workers had returned home. Property damage estimates ranged between $7 million to $15 million.

The Bureau of Mines investigation concluded that the accident was due to the low temperature embrittlement of the inner shell of the cylindrical tank. The inner tank was made of 3.5% nickel steel, a material now known to be susceptible to brittle fracture at LNG storage temperature ( -260°F). In addition, the tanks were located close to a heavily traveled railroad station and a bombshell stamping plant. Excessive vibration from the railroad engines and stamping presses probably accelerated crack propagation in the inner shell. Once the inner shell ruptured, the outer carbon steel wall would have easily fractured upon contact with LNG.

The accident was aggravated by the absence of adequate diking around the tanks, and the proximity of the facility to a residential area. The cause of the second release and explosion from the spherical tank was the fact that the legs of the sphere were not insulated against fire, so that they eventually buckled after being exposed to direct flames.

East Ohio Gas paid more than $3 million in damage settlements to the neighborhood and $500,000 more to families of the dead gas company employees.

The explosion also had a long range impact on the natural gas industry. Until the disaster, above ground storage of natural gas, used as fuel for homes, office buildings and factories, was a common sight in cities across America. Following the disaster, utility companies and communities began to rethink their natural gas storage systems, and below ground storage of natural gas grew in popularity.

Sources

• CR4, LNG explosion rocks Cleveland, Accessed 26 August 2008.
• Ohio History Central, East Ohio Gas Company Explosion, July 1, 2005, Accessed 26 August 2008.
• Cleveland Public Library, Optical Disc Database, Accessed 26 August 2008
• Wikipedia Contributors, Cleveland East Ohio Gas Explosion, Wikipedia, Accessed 26 August 2008.
• Encyclopedia of Cleveland History, Indiana University Press, East Ohio Gas Co. Explosion and Fire, Accessed 26 August 2008.