3 LPG Blasts Follow Derailment Of Tankers, Evacuation of Area
Three BLEVEs, raging flames and dense black smoke caused by a derailment in a 92-car freight train brought on a partial evacuation of the City of Canyon in the Texas Panhandle and an estimated $640,000 loss. Miraculously, there were no injuries or loss of life.
The derailment, which involved 37 cars in the center of the train, occurred on a sharp curve in the tracks at the western edge of the city, a point where the Houston-Denver rails connect with the Santa Fe main line from Chicago to Los Angeles. Traffic on the transcontinental line was stopped for nine hours, causing a massive tie-up of trains along the route.
Ten of the derailed cars were tankers, five of which carried liquefied petroleum gas. One each carried fuel oil, petroleum naphtha and petroleum distillate. An empty cyclohexane tanker and one filled with isobutane provided the rest of this hazardous cargo. As the derailment occurred one of the LPG tankers, along with the naphtha car, was punctured and began leaking its contents. Ignition came just moments after from sparks generated by the grinding metal. It was suspected that the cyclohexane tanker was also punctured in the accident and released its vapor contents into the fire.
The Canyon Volunteer Fire Department with Chief Curtis Lehnick in command received the first call on the derailment at 7:02 on November 22, 1978. They responded with a full assignment of three engine companies, one booster, two tankers, an elevating platform, a rescue squad and a salvage equipment truck.
Upon arrival of the fire department, the conductor of the train was located and the manifest was checked for any hazardous materials. The waybills indicated that the cars involved carried placarded materials. There was some confusion at first since the petroleum distillate tanker was waybilled as “fatty acid.” No reference to fatty acid could be found in the fire department’s hazardous materials library. The fatty acid car did not carry any placard. Railroad officials upon running the train “consist” through their computer checking system determined that fatty acid (a hydrocarbon derivative) did not require any placard and was not classified as a hazardous material. Some of the other cars involved in the derailment contained asphalt road mix, cottonseed meal, lumber and other general freight articles.
After the check of the material involved in the accident and a quick visual check of the burning tankers, Lehnick decided to let the wreckage burn. He also ordered evacuation of the affected area—a 2000-foot radius from the derailment. Police and fire fighters went from house to house and down the streets with mobile public address systems advising everyone to leave the area because of the danger of explosions and fire. Complete evacuation was accomplished in one hour from receipt of the alarm.
A big factor in the decision to let the hazardous material burn was the lack of water for use on the fire. The closest hydrant was 1500 feet away, and not enough lines could be laid to produce the flow required for effective cooling of the tankers in the massive pile-up. Another related problem was that the main power substation for the city was located only 100 yards away from the derailment. Loss of the substation would have meant loss of electricity for the city’s water pumping station. An onscene command post was set up to conduct the operations. Under a mutual aid plan, back-up engine companies from the Hereford, Amarillo and Happy Fire Departments were summoned.
Explosions begin
Shortly after the arrival of the department, the fire began to increase in intensity. At 7:20 a.m., one LPG tanker exploded from what is called a BLEVE and released its contents through a 2foot-square hole blown in the tank. A column of fire shot 400 feet into the air, held for about three to five minutes, then died down to a level of about 100 feet and burned that way for another 20 minutes.
The fire continued for the next 45 minutes and then at 8:05 a.m. another jumbo LPG tanker exploded, sending a column of fire into the air equal to the first. The tanker remained in place but a hole, similar to the first BLEVE was blown in the vessel. The fire once again continued to burn very heavily.
Railroad officials help
In the meantime, railroad officials from the division office were very helpful in supplying information on the products involved in the derailment. A copy of the computer printout on the train’s consist was delivered to the accident site, which confirmed the existence of the hazardous materials that the waybills had shown from the conductor’s list. The fire fighters felt great relief upon finding that no poisonous gases or chemicals were involved in the derailment. Lehnick decided that enough information and experienced persons were available to handle the LPG without having to contact CHEMTREC.
At approximately 9:45 a.m., a sharp buildup in the intensity of the fire occurred. U.S. Highway 60, located approximately three blocks north of the derailment, was blocked at this time to all traffic. The buildup continued until 10:04 a.m., when the third LPG tanker was involved in another BLEVE. The 33,000-gallon jumbo tanker’s end was blown off along with one and a half of the six sections of the tank. This section and a half was flattened out like a piece of tin. The remainder of the flaming tank rocketed from the derailment site and hit a house some 500 feet away, knocking off one room and causing other heavy damage. After striking the house the tank continued across a vacant area, crossed a roadway leading into the yard of another house—narrowly missing it—and finally came to rest some 1500 feet from its original position. The remaining fire in the 60,000-pound part of the tank quickly burned out.
This last BLEVE created a fireball that rose 600 feet into the air and spread some 300 feet across at the bottom. The updraft created by the mushrooming fireball could be felt at the on-scene command post as air, dust and debris were sucked into the cloud. Pieces of the tank and other wreckage were blown as far as one third of a mile from the derailment site. Some of the wreckage weighed hundreds of pounds. The concussion caused by the BLEVE was felt across the entire city.
As a result of the third BLEVE, the remaining tanks of fuel oil and petroleum distillate were ignited. Such a tremendous cloud of black smoke was created that nothing could be seen in the pile-up for some two hours.
No further buildups occurred after the BLEVE and the fire gradually decreased in intensity. By 2 p.m., the fire was burning in the distillate car, the cottonseed meal cars, some general freight cars and some of the other wreckage around the derailment.
Inspecting the wreckage
After careful observing the tankers with binoculars, a decision to inspect the wreckage was made. The main concern at this time was two LPG tankers located on the north end of the derailment that had not been directly involved in the main part of the fire. This inspection was made at 2:15 p.m. by fire department and railroad officials.
After a visual inspection of the two tankers was made for any signs of vessel damage, it was jointly decided to move the tankers from the piled-up wreckage some 150 feet to an open area where they could be righted and fuel could be transferred into other cars. The transfer of the LPG was made on December l and 2, one week after the derailment occurred, and after all wreckage had been removed and all spot fires had been extinguished. Some problems with the fuel valves were encountered during the transfer because of damage from the original derailment. The transfer of the LPG was directed by an American Association of Railroads Bureau of Explosives inspector from Denver, Colo.
The evacuated residents of the affected area were allowed to return to their homes at 4 p.m. on the day of the fire when the possibility of explosions no longer existed. The mutual aid request was returned to their communities after 4 p.m. Two engine companies of the Canyon Fire Department remained on duty to check the remaining fires and allow them to burn out.
Homework paid off
The investigation into the cause of the accident is continuing at this time. It is thought that excessive speed on the curve was a factor in the derailment. No deaths or injuries were sustained as a result of the accident and explosions. Property damage was estimated at $640,000, including damage to railroad equipment, freight loss, product damage, track, signals, and to the home hit by the rocketing tank car.
Because of the heavy rail traffic, much training on hazardous materials has been done by the Canyon Fire Department, which proved beneficial in the accident. Having the knowledge and knowing how to secure the needed information made a big difference in this serious hazardous materials transportation incident.
It was somewhat ironic and fortunate that the author of this article had just returned from an NFPA seminar on handling hazardous materials transportation emergencies that was held in Oklahoma City, November 1-3, 1978. And that the subject for drill on November 15 for the volunteer fire department was handling hazardous materials in transportation emergencies. This fire department’s homework really paid off.
