The Kingman Rail Car BLEVE

Twenty-five years have passed since a railroad tank car carrying propane exploded in Kingman, AZ. Robert Burke revisits the incident and discusses what lessons (if any) were learned.


It was 25 years ago, on July 5, 1973, that a propane tank car being off-loaded in Kingman, AZ, caught fire, resulting in a BLEVE - boiling liquid expanding vapor explosion - that killed 11 Kingman firefighters and one civilian. Captain Wayne Davis is the only firefighter in the area who was at...


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On-The-Scene Photography

Many of the photos of the fire and explosion were taken by Hank Graham, a Santa Fe Railroad conductor. He was working on a short train servicing the industries along the railroad in Kingman when the incident occurred. Graham had been notified of the fire at the Doxol plant and was advised not to proceed into the area. While maneuvering several rail cars, he saw the smoke from the fire. Graham pulled out his camera and started taking photos of the incident. When the train stopped, he proceeded to a point on Route 66 where a police officer was blocking traffic access from the incident. He wanted to know how long the rail line would be blocked.

Graham then began photographing the burning tank car's relief valve and awaited the fireball that would be created when it opened. While he was preparing to take another photo of the flaming relief valve, the BLEVE occurred, burning the hair off of his arms.

In the years since the Kingman explosion, rail cars have been manufactured with an outer layer of insulation and tank skin surrounding the inner tank to provide time before a fire can reach the inner tank. This insulation adds about one hour to the 15-to-20-minute time of flame impingement before a BLEVE is likely to occur.

A recent incident occurred in Weyuwega, WI, where 18 propane and LPG cars derailed and some experienced direct flame impingement. The insulation on the tank cars may have helped prevent a BLEVE from occurring during this 21-day incident. However, stationary and portable propane containers still have no protective insulation. Flame impingement on the vapor surface of these tanks will produce conditions that may lead to a BLEVE.

Others Inspired To Join

Today, the Kingman Fire Department is headed by career Chief Charles Osterman (who was just 16 years old when the explosion occurred) in command of four stations, five engines, a 55-foot TeleSqurt, a heavy support vehicle, an extrication truck, two brush engines and a reserve ambulance. The department's response area has grown to over 30 square miles and the population now exceeds 18,000. Each shift now has eight career firefighters on duty supported by Osterman, two assistant chiefs, an EMS coordinator and a training officer. The career force is complemented by 19 volunteers.

Osterman reports that the incident that occurred 25 years ago this month has led many relatives of the firefighters who were killed - including sons, nephews and uncles - to become career and volunteer firefighters in Kingman and other communities. Osterman's father was a volunteer firefighter in Kingman when the explosion occurred but was at work 22 miles away and missed the call - which may have saved his life.

Robert Burke will discuss "Hazardous Materials Response: Handling The Inci-dent" at Firehouse Emergency Services Expo '98 in Baltimore July 15-19.

What Is A BLEVE?

A BLEVE is a boiling liquid expanding vapor explosion. Gases are liquefied to allow the shipment of large volumes of product more economically. The process involves pressurization of the gas at its critical temperature and critical pressure.

Every gas has different critical temperatures and pressures. The boiling point of liquid propane is -40 degrees below zero Fahrenheit. It remains a liquid because of the pressure in the tank pressing down on the surface of the liquid. Liquefied gases other than cryogenics (refrigerated liquids) exist at what ever ambient temperature is present around the tank - if it is 70F outside, then the temperature of the liquid gas is 70F. Almost any ambient temperature encountered in this country is above -40F. Therefore, liquid propane is existing as a liquid above its boiling point. At 70F it is existing at 110 degrees above its boiling point!

When radiant heat, changes in ambient temperature or flame impingement increase the rate of boiling within the tank, the pressure also increases. Each tank has a pressure relief valve to remove the excess pressure. If, however, the pressure is being increased at a greater rate than it is being removed, or the tank is weakened as a result of flame impingement or mechanical damage to the tank, a BLEVE can occur.