On The Job - Wisconsin

Just before dawn in the east-central Wisconsin farming community of Weyauwega, the early-morning quiet of March 4, 1996, was interrupted by the sounds of crashing metal and burning propane. Thirty-seven tank cars of a Wisconsin Central Railroad train had derailed near an industrial area at the north end of town. It was the beginning of a hazardous materials incident that lasted 18 days, attracted nationwide attention and forced the entire town to be evacuated.

Among the derailed tank cars were seven transporting highly flammable liquefied petroleum gas (LPG), seven more carrying highly flammable liquefied propane gas and two with sodium hydroxide, a non-flammable corrosive material. Initially, three of the derailed cars opened up and the propane and LPG immediately caught fire.

Although characteristics of this incident were similar to widely known incidents that occurred in Waverly, TN, in 1978 and Crescent City, IL, in 1970 (see Firehouse®, December 1995), the outcomes were much different.

In the Waverly accident, in which 12 people were killed, a derailed propane tank car became involved in a boiling liquid expanding vapor explosion (BLEVE). It was cold when the train derailed in Waverly, just as it was in Weyauwega; however, two days into the Waverly incident, the temperature started warming up. This caused the pressure to increase inside the damaged tank car until it exploded.

Crescent City's experience was similar to Weyauwega's in that several propane tank cars derailed in the center of town. Resulting fires impinging on the tanks caused the propane tanks to BLEVE, injuring response personnel and bystanders and causing widespread property damage. In Weyauwega, by contrast, no one was injured and property damage was limited.

The derailment in Weyauwega occurred at 5:55 A.M. The wind was calm and the temperature was about 30 degrees Fahrenheit. Twenty-four volunteer firefighters from the Weyauwega Fire Department were on the scene within five minutes, led by Assistant Chief Jim Baehnman Fire Chief Gary Hecker was away on vacation when the accident occurred; he returned the second week of the incident but left Baehnman in charge.

Upon arrival at the scene, Baehnman took command and immediately established the incident command system. The derailment had blocked the rail crossing on Mill Street, so it was difficult to determine what was happening on the north side of the tracks. Fires were burning, with large fireballs 200 to 300 feet high and visible at times 13 miles away.

It appeared that there were three separate fires. The first was a large fire fed by a damaged tank car at the intersection of Mill Street and the railroad crossing. The second fire involved a feedmill 75 yards east of the crossing. The third fire was 75 yards west of the crossing and involved a storage building. It is believed that the third fire was started by power lines downed by the derailment.

Sizing up the situation, Baehnman realized that the incident was beyond local capabilities and asked for assistance from neighboring communities, the state of Wisconsin and Region V of the U.S. Environmental Protection Agency (EPA). Fire departments from Clintonville, Fremont, Iola, Manawa, Mukwa, Navarino, New London, Poysippi, Scandinavia, Tustin, Waupaca and West Bloomfield responded with apparatus and over 200 firefighters. (Several days into the incident, a rescue truck built by Pierce Fire Apparatus in Appleton, WI, and sold to the Glen Cove, NY, Volunteer Fire Department was sent to Weyauwega and allowed to be used in the operation, courtesy of the Glen Cove department.)

Many mutual aid personnel were used to man roadblocks and help staff the command center. Radio communications quickly became a problem because of the volume of traffic from all of the responding agencies. Additionally, agencies from the private sector as well as the state and federal governments responded, including Region V EPA from Chicago, IL, Wisconsin Department of Natural Resources (DNR), State Emergency Management, the governor's office, Wisconsin National Guard, state EPA, Federal Railroad Administration, American Red Cross and Salvation Army.

The first-responding firefighters found a tangled mass of railcars, broken rails and a large volume of fire. The derailment occurred near a feedmill and the spreading fire was already impinging on feedmill structures and several grain and propane vehicles. Initial efforts were focused on fighting the fire in the feedmill and protecting exposures. The firefighters were lucky to the extent that a fertilizer building across from the feedmill had not received its spring shipment of fertilizers and pesticides. A cheese factory a block south of the burning tank cars had anhydrous ammonia pipes on its roof. If a BLEVE had occurred, those pipes could have been damaged by flying tank parts, causing an ammonia leak.

Initially, the firefighters' view of the incident scene was obscured by the large volume of fire and darkness. They were unaware of the tank cars of hazardous materials that were involved in the derailment and subsequent fire. Reports from first-responding firefighters are conflicting as to the exact time it took to recognize that the burning tank cars contained propane and LPG; estimates range from 10 minutes to one hour. Wisconsin Central Railroad personnel advised the firefighters that the construction of the tank cars would allow them to withstand fire for approximately 11/2 hours. When this information was received, it was already one hour into the incident.

Once firefighters realized propane and LPG tanks were involved in the derailment, and on fire, a decision was made to pull back. Firefighters abandoned their hoselines in the streets when they realized the seriousness of the situation. (The abandoned hoselines were later damaged when they froze and were driven over by cleanup and restoration personnel.)

In addition to pulling back response personnel, Baehnman ordered the entire city evacuated. Fire, police, and EMS personnel made notifications of the evacuation by going door to door while the local radio station provided additional announcements. As each residence was evacuated it was marked with a yellow tag so that other emergency responders would know the building had been cleared. Approximately 1,700 people were evacuated from Weyauwega and another 600 from surrounding rural areas. Most people, once notified, evacuated in personal vehicles. Two nursing homes with over 200 total patients were evacuated and taken to a hospital and other nursing facilities in nearby communities. (A tractor-trailer driver who had parked his truck at a gasoline station less than 100 feet from the scene slept through the derailment and initial emergency response efforts. An attendant at the gas station had to awaken the truck driver to tell him to evacuate.) Once the city was completely evacuated, Baehnman made the decision that no emergency response personnel would enter the city.

Weyauwega residents displaced by the derailment and fires were directed to an evacuation center set up at a former gymnasium in Waupaca, seven miles away. Many of them, however, instead opted to stay with relatives or in hotels provided by the railroad. They would not be allowed to return home for 18 days. Pets were not considered in the initial evacuation but as the incident progressed, more and more citizens became concerned about the pets they had left behind. Baehnman felt that rescuing pets was not worth the risk to personnel and the public; however, he was later overruled by the governor. The National Guard was activated and one of its first jobs was to rescue pets in a small portion of the city farthest from the accident scene.

The air space within 10 miles of the derailment was restricted to reduce curiosity flights and to control the news media; the distance was reduced to five miles the fourth day of the incident. Helicopters and fixed-wing aircraft performed aerial surveillance to locate spot fires and determine the extent and effectiveness of the evacuation. For the first few days after the incident, aerial photographs were the only means of viewing the incident scene.

Initially, power was cut to about 15 to 20 percent of the homes in the area to control ignition sources immediately around the derailment. Natural gas service was also cut. As a result, up to 95 percent of the homes were without heat, which caused water pipes to freeze but only about a dozen homes were severely damaged. The main natural gas feeder line into the community ran directly under the derailment site next to Mill Street. Responders were concerned that the line may have been damaged as a result of the derailment, which prompted the decision to shut down the line.

Another problem was obtaining the necessary number of telephones to complete the calls to deal with the incident. The local telephone company brought in 40 lines by noon on the first day of the incident.

The"emergency" response phase of the incident only lasted until approximately 10:45 A.M. on the day of the derailment. Evacuation of the city had been completed by this time, along with the relocation of response personnel to a position past the command post, which was now 11/4 miles from the derailment scene. At this point, the focus turned to stabilization, clean-up and restoration of the incident scene, which took the next 17 days to accomplish.

Hazmat Teams Called In

The first hazmat team arrived on the scene within one hour after the derailment occurred. The railroad, which had conducted exercises on this type of incident using the incident command system, brought in hazardous materials clean-up experts from contract companies, along with an operations supervisor to coordinate railroad activities with the incident commander. Hazmat teams also responded from Appleton, Oshkosh and Stevens Point and Brown and Waupaca counties.

Because of the potential dangers of the burning propane and LPG tanks, the hazmat teams were assigned an advisory role until companies hired by the railroad arrived on the scene. These contract companies worked closely with the incident commander, the hazmat teams, the railroad and environmental agencies to determine the best course of action based on the condition and positions of the propane and LPG tank cars.

Temperatures during the incident ranged from daytime highs of 15 degrees to 40 degrees F to nighttime temperatures of -5 to 25 degrees F. As the incident progressed, the weather forecast was for warmer temperatures that would cause the pressure to increase inside the derailed tanks much like the increased pressure that occurred in Waverly that caused the BLEVE of one of the rail tank cars there.

The emergency response personnel assumed a role of support for the contractors during the process of stabilizing the burning and damaged tanks. Unmanned monitors were placed into service on the third day of the incident as the pressure fires subsided and about a half dozen propane and LPG tanks still had minor fires burning. Off loading of the tank cars was not undertaken because it was unknown what the extent of damage was to the cars.

After an evaluation of the derailment site, the decision was made to "hot tap" some of the propane and LPG cars to transfer the remaining fuel to a burn pit where it was allowed to burn off. The outer cars were tapped first and tapping moved inward until the last car was reached which could not be hot tapped due to its position.

Hot tapping has been used successfully for many years in the chemical and petroleum industry but has limited applications in tank car accidents. The process involves the welding or securing of a tapping to a vessel (such as a tank car) while it still contains gases or liquids. The tank is then drilled through a valve attached to the tapping fitting. A special drilling machine is used which threads the valve and reduces leakage. Once the drill bit penetrates the vessel wall, the drilling machine is removed from the valve. (Hot tapping should only be attempted by trained and experienced contract personnel. This is NOT an emergency response function.)

Because of the potential danger to personnel, tanks containing certain commodities should not be tapped. They include: acetylene, ethylene, ethylene oxide, halogens, elemental sulfur, hydrocarbons in stainless steel tanks, cryogenics, hydrogen, acids, oxygen, and tank cars operating at below atmospheric pressure. Once the tank is tapped, nitrogen is injected into the tank forcing the liquid through the tap valve to a flexible hose connected to a pump and then into a burn pit through a hard pipe, where the liquefied compressed gas is then burned in a pool fire. The liquid is burned off until the tank is empty.

The process of hot tapping and "flaring" took the most time in the stabilization process. Fire department personnel stood-by with charged hoselines and rescue equipment to protect the contract personnel performing the hot tapping and flaring operations. Personnel from one company reported they had "never experienced an incident with circumstances that were as difficult or as large as Weyauwega." Baehnman indicated that "the total amount of liquefied gases involved was over 1 million pounds, which is reported to be the largest incident ever in the United States in terms of volume."

All but 10 percent of the last remaining tank car was showing above ground, so a decision was made to vent and burn the tank car because of a large rapid pressure increase in the tank. (Vent-and-burning had not been an option early in the incident because of the large number of tank cars and their close proximity.) Charges were placed on each end of the tank, opening it up to allow the remaining propane and LPG to burn freely. Venting a tank involves the placing of shaped explosive charges on the high end and low end of a damaged tank car. The resulting explosion opens up the tank car and allows the product to drain out and burn.

Firefighters were fortunate that no explosions occurred involving the propane and LPG tanks before the decision was made to move to a safer location. The National Fire Protection Association (NFPA) says that BLEVE times range from eight to 30 minutes, with the average being 15 minutes. The initial evacuation of personnel was two blocks for the first hour, then expanded to seven blocks and finally to 11/2 miles. The U.S. Department of Transportation's Emergency Response Guidebook (ERG), under Guide 22 for propane and LPG, recommends an evacuation distance of a minimum of a half mile if propane or LPG tanks are on fire.

As the days passed, the evacuated residents wanted to know when they would be allowed to return to their homes, so briefings were held each afternoon in three locations to update them on the progress of the incident. The incident commander cited the Waverly and Crescent City derailments to illustrate to the people what can happen when propane and LPG tanks BLEVE. This information helped people understand why they couldn't go back to their homes until they were told it was safe to do so.

There were no injuries to emergency responders or residents directly resulting from the derailment. One resident suffered an elbow injury from a fall during the initial evacuation; however, she was able to continue evacuating on her own. Another resident had a heart attack upon returning home; her home was not damaged and the heart attack was not attributed to the incident. Baehnman said "from the start of the incident, the tone of the incident would be driven by safety and not time." This approach and the fact that no BLEVEs occurred likely accounted for the lack of injuries to response personnel and civilians, and the minimal loss of property.

During and after the incident maintenance problems were experienced with some fire apparatus that had been constantly idling for almost three weeks at road blocks without being shut off. The primary breakdowns involved motors and electrical generators on the motors.

The cause of the derailment was thought to be a switching gate that malfunctioned or a section of broken rail. The accident is under investigation by the National Transportation Safety Board (NTSB) and a report should be out by the end of 1996.

Robert Burke, a Firehouse® contributing editor, is a Maryland-based certified Hazardous Materials Specialist and has served on state and county hazardous materials response teams. He has 16 years' experience in career and volunteer fire departments, attaining the rank of assistant chief, and has served as a deputy state fire marshal. He holds an associate's degree in fire protection technology and a bachelor's degree in fire science. Burke is an adjunct instructor at the National Fire Academy and the Delaware County, PA, Fire Academy.