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 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.

 

Tragic consequences

One possible contributing factor to the incident indicated by the National Transportation Safety Board (NTSB) was an increase in pressure in the tank. Ambient temperature increases can cause the pressure in a tank to increase. Also unknown at the time was that a portion of car 83013 had been damaged and weakened by the derailment. Tank cars that are piled up on each other or banged into each other may sustain damage. Moving them before off-loading the product can lead to further damage or catastrophic tank failure, which occurred in Waverly. The combination of the two factors may have resulted in the BLEVE involving tank 83013.

Monitoring of the air with combustible gas indicators revealed no leaks or propane in the area. The evacuation was relaxed and Waverly was back to business as usual by the time the off-loading was to begin. The fire chief, police chief a fire crew, and two representatives of the state civil defense were on scene, along with L&N workers and personnel from the Liquid Transport Co. involved in the off-loading.

Nearly all recommendations put forth by the fire department to provide safeguards were overruled by the railroad. Numerous pleas by the director of the local private ambulance service for safety measures fell on deaf ears. One such plea, the last, occurred within a half-hour of the explosion. Fortunately, the ambulance director, a 30-year veteran of emergency response, saw the potential hazard and withdrew his personnel to a safe location and the explosion did not affect them. Another problem identified, which undoubtedly contributed to increased loss of life and injuries, was the lack of scene security and lack of evacuation of the public during the potentially dangerous cleanup and off-loading procedures. Following the initial evacuation when the derailment first occurred, everyone was allowed to return home or to their businesses. Many unnecessary people were allowed into the danger zone of the derailment and became victims as a result.

Prior to initiation of the off-loading process, at 2:58 P.M., someone noticed propane vapors leaking from car 83013. Before anyone could react to the leak, a BLEVE occurred. The resulting fires and explosion killed five people instantly and severely burned the Waverly fire chief (he later died at a hospital). The hoselines that had been left in place were shredded by the explosion. Parts of the tank car, burning propane and debris were scattered over a wide area. One piece of the tank car was propelled 330 feet by the explosion. Noise and blast pressure from the explosion were felt several blocks away. Numerous large buildings, vehicles and railcars were set on fire by heat from the fireball. A second propane tank car was set on fire by the explosion, but did not BLEVE.

After several BLEVEs of this type in the 1970s, the railroad industry began to retrofit all tank cars carrying liquefied flammable gases by adding thermal protection, which guards against high temperatures that can weaken metal. Shelf couplers were developed to prevent cars from uncoupling vertically and head shields were fitted to protect against punctures from the couplers.

Today, the population in Waverly is 4,186. Fire protection is provided by the Waverly Police Department with 12 officers who double as firefighters when called on, along with three full-time city employees from other departments who receive a firefighting pay supplement and 12 volunteers who are paid on call. Firefighters operate three engine companies and a hazmat trailer donated by the CSX Railroad and operate out of two fire stations.

The Waverly Fire Department has an Insurance Service Offices (ISO) rating of 4. EMS is provided by a private company contracted by Humphries County, although Waverly police vehicles carry automated external defibrillators (AEDs) and officers are trained in CPR.

Although the incident in Waverly marked the last time such a large number of deaths and injuries occurred involving propane railcar explosions and fires, incidents involving leaking propane from railcars and other types of containers occur on a regular basis at propane companies, commercial structures and in residential occupancies across the U.S. and Canada.

Three employees were critically burned in a propane explosion at a propane company in Hope Mills, NC, in October 2004. One of the injured died later in a hospital. Firefighters fought the resulting fire for three hours before letting it burn itself out. There were no reported injuries to firefighters.

Four people, including two emergency responders, were killed and five others were seriously injured in a propane leak and explosion in a small stationary tank at a convenience store in Beckley, WV, in January 2007. Response personnel called to a leak at the commercial occupancy were investigating when the deadly explosion occurred. According to the U.S. Chemical Safety Board (CSB), 30 minutes elapsed between the report of the leak and the explosion.

An off-duty chief officer suffered a fatal heart attack while at a fire at a propane depot in Toronto, Canada, in August 2008. The five-alarm fire involved numerous explosions at the facility. Residents within a mile of the scene were evacuated. Six people were transported to hospitals, 18 other went to hospitals on their own and EMS personnel treated approximately 40 others.

For additional information about the Waverly incident, contact W.B. “Buddy” Frazier, currently the Waverly city manager, who was a police officer at the time of the 1978 explosion and later the chief of police, at bfrazier@waverlytn.org. n

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