Hazmat Studies:Tennessee Propane Blast: A Turning Point for Hazmat

The deadly train derailment and ultimate propane explosion that occurred in Waverly, TN, 35 years ago this month was a watershed event in hazardous materials incidents in the U.S. Sixteen people, including four active emergency responders, died from the...


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The deadly train derailment and ultimate propane explosion that occurred in Waverly, TN, 35 years ago this month was a watershed event in hazardous materials incidents in the U.S. Sixteen people, including four active emergency responders, died from the explosion and resulting fireball, 43 people were hospitalized with injuries and numerous other injured people were treated as outpatients. Sixteen buildings were destroyed and 20 others damaged.

In terms of loss of life to emergency responders and civilians resulting from train derailments, the Feb. 24, 1978, incident was the last in which so many people died. The Waverly incident also resulted in many changes in both tactics for dealing with liquefied petroleum gas (LPG) fires in containers and safety equipment on railroad tank cars. A detailed account of the Waverly disaster was featured in my February 2003 Hazmat Studies column; the following is a summary with additional commentary.

Feb. 22, 1978, was a Monday. Temperatures hovered in the mid-20s with about a half-inch of snow on the ground. At about 10:30 P.M., a Louisville and Northern (L&N) train heading from Nashville to Memphis derailed in this small community. Investigators determined that a wheel on a gondola car, overheated from a handbrake left in the applied position, broke apart east of Waverly. A wheel truck damaged by the breaking wheel remained with the train for seven miles before coming loose from the car and causing the derailment. Twenty-four of the train’s 92 cars left the tracks in downtown Waverly. Two of the derailed tank cars, which contained LPG, played a major role in the incident that unfolded over the following several days.

Propane vapor is heavier than air and extremely flammable. When LPG is in a container, a boiling liquid/expanding vapor explosion (BLEVE) can occur under certain conditions, including direct flame impingement on the vapor space of the container, overpressurization of the container, damage to the container shell or a combination of factors. When the derailment occurred, there were no leaks, fires or explosions. This might have been a primary factor in the disaster two days later.

 

First on the scene

Waverly Fire Department volunteers, along with Waverly police, were first on the scene. Responders had no monitors to check for leaks and relied on their sense of smell to determine there was no immediate danger. Without monitoring equipment, however, there is no way to know what amount of vapor is present or whether the vapor is within its flammable range. Also, responders may become asphyxiated without proper respiratory protection.

Following the initial scene survey, a nearby single-family home and a custodial-care facility were evacuated as a precaution. The state civil defense agency was notified the following morning of the derailment. Initial reports indicated no hazardous materials were involved, but at 5:10 A.M. on Feb. 23, civil defense authorities were told that hazardous materials were in some of the derailed cars. With that information in hand, a state hazmat team was dispatched and arrived in Waverly at 6:30 A.M. Once the team was on scene, an additional evacuation distance of a quarter-mile was implemented and all electrical and natural gas sources were shut off in the hazard area.

Local firefighters had already placed heavy hose streams in place for cooling the derailed tank cars as railroad personnel began clearing the right-of-way to get rail traffic moving again as quickly as possible. The railroad personnel complained the mud created by the “cooling” efforts of firefighters was making it difficult for their workers, so the hoselines were shut down, but left in place.

By 2:15 P.M. on Feb. 23, the rail line was cleared of all derailed cars. One derailed tank car, 83013, had been moved 12 feet from its original resting point underneath several other rail cars. The L&N line was once again opened to limited rail traffic at 8 P.M. To that point, no efforts had been made to deal with the propane still in the tank cars. Crews that were dispatched to off-load the propane tank cars arrived at about 1 P.M. on Feb. 24. The sun had raised the temperature into the mid-50s.

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