BY LARRY L. WILES
The Nebraska City (NE) Volunteer Fire Depart- ment (VFD) was confronted with a confined space fire involving hundreds of tons of shredded rubber tires in four 28-foot 2 64-foot steel silos located within 100 yards of the Missouri River. An explosion 11 hours into the fire sent 13 firefighters to the hospital. Two of the silos were leaning, making it impossible to gain access through the top of the silos. Runoff water had to be diked to prevent contamination of the river. Extinguishment of this first fire of its type required 187 hours of firefighting and the assistance of an international oil well firefighting company and the U.S. Environmental Protection Agency (EPA). Thirty-plus area fire departments were summoned at various times to provide mutual aid to the department. The estimated cost of extinguishment was $1.5 million.
The incident involved the following agencies: the Nebraska City VFD, the Nebraska City Administration, the Otoe County Administration, the Nebraska City Police Department, the Otoe County Sheriff’s Department, St. Mary’s Hospital, the Nebraska State Fire Marshal, the Nebraska Emergency Management Agency, the Federal Emergency Management Agency, the EPA, the U.S. Coast Guard, Williams Fire and Hazard Control, and 33 area volunteer fire departments and rescue squads.
THE FIRE
The fire occurred at a tire recycling facility owned by EnTire Recycling, Inc. of Nebraska City. The facility the company used was a former grain storage elevator consisting of four steel 64-foot-tall silos; one 40-foot-tall corrugated steel silo; and two 80-foot 2 300-foot steel buildings and related conveyors, augers, and stiff legs. The stiff leg is an enclosed auger used to transport rubber to the top of the silo and then into the silo for storage. Rubber inside the auger assembly was burning. The company obtained used tires of all sizes and, through a processing procedure, ground the tires into a 20-mesh powder. The powder was then used to make floor mats and, when mixed with soil, as a shock-absorbing surface for football fields and tracks. The process calls for the raw tire to be cut into small sections and then cut into pieces about two to three inches in size, which are then frozen using liquid nitrogen and ground into the final powder. The two-inch pieces are called “crumb rubber” and, depending on the type of tire (steel—photo 1, or bias-belted—photo 2) will have embedded fine wire or nylon strands. The crumb rubber is stored in vertical 64-foot-tall steel silos before it is moved by conveyor belt into the grinding facility.
 (1) Steel-belted tire “crumb” rubber. (Photos courtesy of author.) |
null
 (2) Bias-belted tire “crumb” rubber. |
null
A number of factors added to the fire’s complexity: It was the first fire of this type in the United States involving crumb rubber stored in a confined space silo; 30 percent of fire department personnel were injured by an explosion that occurred during a “mop-up” situation; massive mutual-aid resources (equipment and personnel) were used during the entire operation; and there are no fire codes for this type of storage.
At 2:54 a.m., Wednesday, January 23, 2002, the 9-1-1 center received a call from an elderly woman living at Riverview Terrace (a nearby high-rise apartment building) reporting a fire “at the tire place by the elevator.” The alarm was paged as “A reported fire at the fire place by the elevator at Riverview Terrace.” The first-out engine responded to Riverview Terrace; however, responding police officers found the correct location, and the second engine, aerial tower, heavy utility unit, and EMS unit responded to the EnTire facility.
On arrival, fire personnel found a fire in the crumb rubber around the base of the silos and in one of the silos and the stiff leg to the top of the silos (photo 3). They made numerous attempts using master streams and handlines to get to the burning rubber, but every time a fire was extinguished it would reignite as soon as the water was removed.
By 6 a.m., the fire department had brought in the street department to build sand dikes (photo 4) to contain the runoff water. The facility was about 300 feet from the Missouri River.
 (3) On the arrival of fire units, fire was coming from the top of the silo stiff leg and around the base between the silos. |
null
 (4) Diking runoff water to prevent contamination of the Missouri River. |
null
The state fire marshal notified the state EPA, which in turn requested assistance from the U.S. EPA in Kansas City. By 6:30 p.m., a task force from the EPA arrived in Nebraska City with personnel and equipment to deal with the water runoff and to monitor the air quality.
About mid-morning the next day, after the owner and several deputy state fire marshals who had responded at the request of the fire department consulted with fire personnel, it was decided to introduce nitrogen gas into the silo to displace the oxygen and hopefully extinguish the fire.
 (5) The aftermath of the silo explosion, which injured 13 firefighters. |
null
 (6) A fire truck splattered with hot rubber from the explosion. |
null
At an opening in the bottom of the silo, a 20-foot metal pipe was forced into and through the rubber to a level above the rubber line. A 21/2-inch fire hose was attached to the pipe and then to the nitrogen pump. After two hours of pumping approximately 8,000 gallons of nitrogen gas into the silo, the fire had not decreased; if anything, its intensity increased.
At this time it was decided that the fire department would withdraw to some extent, almost to an overhaul mode. Three mutual-aid fire departments were released, and a portion of the Nebraska City equipment and personnel were returned to service. An engine, a heavy utility, and an EMS unit remained on the fireground. About 25 firefighters and plant employees were watching the fire and extinguishing small fires where accessible. Fire department officers, state fire officials, and plant managers met to determine what the next course of action would be.
At 1:13 p.m., one of the four silos exploded (photo 5), injuring 13 firefighters—30 percent of the fire department. An alarm for Nebraska City was sounded, with two engines, an aerial, three EMS units, and all available fire and EMS personnel responding. Mutual aid was again called; 16 area communities responded with nine engines, one aerial, two tankers, three utility trucks, 12 EMS units, and an EMS helicopter.
The exact cause of the explosion has not been determined. However, it is theorized that as the nitrogen was pumped into the void above the rubber line, the initial nitrogen that came out was liquefied and caused the top layers of the rubber to freeze, forming a seal. This sealed the nitrogen gas between the top layer of rubber and the top of the silo. As firefighters later worked from below to remove the rubber through the opening in the side of the silo, it is possible that a break in the seal occurred, which allowed for a “cold explosion” as a large amount of nitrogen vapor escaped instantaneously. There was a fireball eruption from the silo opening but there was no sustained fire and the explosion generated no heat. No one in the path of the debris was burned. Essentially, it was similar to driving a nail into the side of an aerosol can.
St. Mary’s Hospital activated its disaster plan and called in all off-duty staff and requested all of the medical staff at Physician’s Clinic to report to the hospital. The hospital administrator placed St. Elizabeth Burn Center (in Lincoln) on alert and asked the Lincoln Fire Department for more ambulances if needed for transport. Twenty-five people were involved in the explosion; 13 were sent to the hospital for treatment. Three required hospitalization, one was transferred to Lincoln Hospital, three were removed from duty to recover, and the remainder were allowed to return to duty. Firefighter injuries included a compound leg fracture; two ankle injuries; and numerous contusions, scrapes, and cuts. No firefighters were burned. The estimated hospital emergency room cost was $13,405.78.
Everything in the path of the flying hot fire-softened crumb rubber was damaged. The impact of the rubber was similar to being hit by a hard snowball that splatters on contact (photo 6).
 (7) Silos shifted during the first six days until the two south silos collapsed. |
null
 (8) The head house falls over on top of the two south silos |
.
 (9) The fire intensifies after the collapse of two silos containing “crumb” rubber. |
null
 (10) Class B foam is applied to contain the intense fire fed by the smoldering rubber that had been exposed to air. |
null
Equipment damaged or destroyed included four SCBAs, 16 sets of bunker coats and pants, 13 pairs of boots, six helmets, 15 hoods, three hand lanterns, one portable radio, one 21/2-inch siamese monitor, one 500-gpm combination nozzle, 400 feet of 13/4-inch hose, 200 feet of three-inch hose, and 100 feet of five-inch hose. The approximate cost of the damaged equipment was $37,049.
By 5 p.m., the situation was stabilized, and the mutual-aid departments were again released. The fire had once again returned to a smoldering fire confined to the silos, which were by this time leaning out of plum about 18 inches.
On Friday (day 3), the insurance company for the owner agreed to call in Williams Fire & Hazard Control as a consultant to the fire department in an attempt to extinguish the fire. Dwight Williams and Chauncey Naylor arrived from Texas on Saturday afternoon; after consultation with the owners, the insurance company, the EPA, and city and fire department officials, it was agreed that the EPA would take over the financial responsibility of the fire under the authority of the Oil Pollution Act. The EPA then hired Williams to assist the fire department. The insurance company wrote the EPA a check for the amount of liability coverage and walked away from the fire.
Williams brought in additional equipment and a large supply of Class B foam. Working with the fire department, Williams reevaluated the situation and developed a new strategy for extinguishing the fire. Heavy equipment and large cranes were brought in; it was believed that the only way to extinguish the fire was to dismantle the silos.
Because of the danger in dismantling the silos and the fact that the fire was a smoldering fire that wasn’t going anywhere, actual operations were conducted only during daylight hours. From 6 p.m. until 6 a.m., mutual-aid fire departments were on a fire watch. Nebraska City firefighters and several mutual-aid departments monitored the fire during daytime operations.
During the weekend, the silos continued to shift (photo 7) slightly. On Monday (day 6) at 8 a.m., the head house laid over on its side on top of two of the silos (photo 8). At 10:16 a.m., the silos started shifting again; by 10:23 a.m., two of the four silos were on the ground with a massive fire burning as a result of the silos’ bursting open, which introduced air to the smoldering fire (photo 9). The fire was threatening the south building of the complex, requiring an aggressive attack to prevent the fire’s spreading. Two three-inch handlines with 21/2-inch foam nozzles were placed in operation to control the fire spread (photo 10). For a period of about 20 to 30 minutes, foam was applied at the rate of five gallons of concentrate every 15 seconds.
 (11) Removing the steel debris of the silos to access the burning rubber. |
null
 (12) Wind chill temperatures dropped to -24°, causing ice to cover the burning rubber and hampering extinguishment. |
null
 (13) Using a specially equipped backhoe, crumb rubber is removed from one of the two remaining silos. |
null
For the next four days, the fire department continued to fight the fire; it was a slow process because the steel debris had to be removed from the rubble (photo 11) and then the rubber had to be extinguished, removed, wet down again, and then hauled to an approved landfill 100 miles away.
On Wednesday (day 8), construction workers arriving at 7:30 a.m. found that a new warehouse they were building had a heavy smoke odor. After making a quick inspection of the building, the fire department was summoned with a report of “See smoke, see no fire.” The department responded at 7:33 a.m. to the site two miles southwest of Nebraska City. The arriving assistant chief reported a working fire in an 80-foot 2 250-foot warehouse under construction, with smoke coming from all of the roof eaves and vents. The closest hydrants were about two miles away. Mutual aid was again called, as firefighters were still involved in the rubber fire and were exhausted. Responding from Nebraska City were a pumper, two tankers, a heavy rescue/utility, and an aer-ial tower.
Tankers were requested from mutual aid. Dispatchers overreacted in summoning these tankers: Approximately 30 tankers were on location within 35 minutes of the initial alarm.
The fire was quickly located and brought under control; it took about an hour to extinguish it. Damage was estimated at $20,000.
Weather conditions worsened after eight days; a winter snowstorm dumped nine inches of heavy wet snow on the fire scene. Temperatures dropped to sub-zero at night; highs during the day were only 10 degrees warmer. Wind chill factor temperatures reached 1257. Needless to say, the weather added to the difficulty of dismantling the remaining silos and extinguishing the fire (photo 12).
 (14) Removing rubber from a silo. |
null
 (15) Extinguishing the fire in the burning crumb rubber after its removal from the silo. |
null
By 6 p.m. on Thursday (day 9), removal of the two south silos had been completed. Because the fire department was operating with a minimum number of personnel (many had returned to their jobs) and the critical operations had been completed, EPA officials and city officials agreed that the fire would be turned over to the Williams company for complete extinguishment, which, it was estimated, would take another nine days. The operation was going to be more of a demolition and removal operation than an actual firefighting operation. The fire department would remain available if conditions worsened.
At 8 a.m. on Friday, February 1, Williams Fire & Hazard Control assumed command and control of the fire scene. Williams hired eight firefighters and a pumper from the fire department to assist with the demolition of the remaining two silos and extinguishment of the fire (photos 13, 14, and 15).
The fire was finally extinguished at 10:50 a.m. on Sunday, February 3, after 11 days. The EPA remained on location supervising the cleanup of the site until mid-March. The EPA estimated that the cost of extinguishment and debris cleanup exceeded $1,500,000.
- Obtain as much information as possible from the property owner or representative concerning the materials involved in the fire, but don’t let the individual decide on how to fight the fire or interfere with fireground operations.
- If the fire is in a confined space and not easily accessible, don’t assume it isn’t going anywhere.
- Never treat a smoldering fire as a “mop-up” situation.
- Don’t hesitate to request assistance from outside sources if the fire exceeds the capabilities of the fire department.
- If outside assistance is provided, cooperate; don’t get into a “turfdom” mode.
- Provide as much information as possible to other agencies involved with the fire operation. Know what your resources are, from local (mutual aid, etc.) to state and national levels.
- Know the capabilities of your communications system.
- Document everything that happens to create a “paper trail” for any decisions made.
- Establish a fireground perimeter, and don’t allow anyone inside the perimeter who is not a part of the actual fireground operation. This includes firefighters, law enforcement officers, and media personnel.
- Appoint a public information officer, who will be responsible for all news releases.
LESSONS LEARNED
LARRY L. WILES, public information officer for the Nebraska City (NE) Volunteer Fire Department, has been a volunteer firefighter for 32 years. For the past 23 years, Wiles has been fire resource manager for the Nebraska Forest Service, providing assistance in all aspects of fire protection management and planning to rural fire districts and municipal fire departments. Wiles has instructed at the annual Nebraska State Volunteer Firefighters Association State Fire School for 28 years.
