More than 150 firefighters and 30 fire engines were called to a blaze at London’s King’s Cross St Pancras tube station, a major interchange on the London Underground. The November 18, 1987 blaze was the worst fire in the history of the London Underground, and it all began when a match was dropped on one of the wooden escalators. Smoking on underground trains was banned in July 1984, over three years before the fire, but smokers often ignored this and lit cigarettes on the escalators on their way out.
The fire started under a wooden escalator that served the Piccadilly line, and, at 7:45 pm, erupted in a flashover (a rapidly spreading fire across a gap because of intense heat) into the Underground’s ticket hall, killing 31 people, including a senior ranked firefighter, and injuring 100. The fire was declared out at 1:46 am the following morning.
Although it started as a small fire, described by one firefighter as “about the size of a large cardboard box,” it quickly became much more serious. The flames heated the framework and decking of the Piccadilly line escalator, pre-heating the rest of the wooden staircase before bursting into flames. Investigators labeled this conflagration behavior as the “trench effect.” (LFB, n.d.)
At about 7:30 pm, several passengers reported seeing a fire on a Piccadilly line escalator. Staff and police went to investigate, and upon confirming that there was a fire, radio dispatched for the Fire Brigade. The fire was beneath the escalator, and it was impossible to reach it to use a fire extinguisher. Four fire trucks and a turntable ladder were sent at 7:36 pm by the London Fire Brigade. The police made the decision to evacuate the station at 7:39 pm, using the Victoria line escalators. A few minutes later, several firemen went down to the escalator to assess the fire. They saw a fire about the size of a large cardboard box and planned to fight it with a water jet.
At 7:42 pm, the entire escalator was aflame, producing superheated gas that rose to the top of the shaft that enclosed the escalator. There, it was trapped against the tunnel ceiling, which was covered with many layers of old paint. As the superheated gases pooled along with the ceiling of the escalator shaft, the layers of paint began to absorb the heat. A few years before the fire, the Underground’s director of operations had warned that the accumulated paint might pose a fire hazard. However, painting protocols were not in his purview, and his suggestion was widely ignored by his colleagues.
Many passengers escaped using an alternative escalator, and all trains had been instructed not to stop at the station; however, the ticket hall was still busy when the fireball erupted from the stairwell. The time on the clock at the top of the escalator read 7:45 pm—the exact moment when the flames burned through its wiring and erupted in a flashover.
A jet of flames shot up the escalator shaft, filling the ticket hall with intense heat and thick, black smoke, killing or seriously injuring most of the people still in it. Trapped below ground were several hundred people who escaped on Victoria line trains. A police constable found a seriously-injured man and tried to evacuate him via the Midland City platforms but found the way blocked by a locked bostwick gate, which was finally unlocked by a passing cleaner.
Fire Brigade Station Officer, Colin Townsley, was down in the ticket hall at the time of the flashover. He was killed in the fire; his body was found beside that of a badly-burned passenger at the base of the exit steps to Pancras Road. It is believed that Townsley spotted the passenger and had stopped to help her. An initially unidentified man, commonly known as “Michael”—or “Body 115” after its mortuary tag—was identified on January 22, 2004, when forensic evidence confirmed that he was 73-year-old Alexander Fallon of Falkirk, Scotland.
The Investigation and Causal Factors in the Disaster
A public inquiry into the incident was initiated by Prime Minister Margaret Thatcher. It was conducted by Desmond Fennell OBE QC, assisted by a panel of four expert advisers. The inquiry opened on February 1, 1988, and closed on June 24, 1988, after 91 days of evidence collection. Investigators reproduced the fire twice—once to determine whether grease under the escalator was ignitable, and the other to determine whether a computer simulation of the fire, which would have determined the cause of the flashover, was accurate.
It was determined that the fire had not been started deliberately, as there was no evidence that an accelerant had been used, and access to the site of the fire was difficult. Investigators found charred wood in eight places on a section of skirting on an escalator and matches in the running track, which evidenced that similar fires had previously started at various points in time but had burned themselves out without spreading.
The inquiry found that the fire was most probably caused by a traveler who had discarded a burning match that fell down the side of the moving staircase onto the running track of the escalator. The fire seemed to be minor until it suddenly increased in intensity and shot a violent, prolonged tongue of fire and billowing smoke up into the ticket hall. This sudden transition in intensity, and the spout of fire, was due to the previously unknown “trench effect,” discovered by the computer simulation of the fire and confirmed in two scale model tests.
Investigators found a buildup of lubricant grease under the tracks, which was believed to be difficult to ignite and slow to burn once it started, but it was noted that the grease was heavily impregnated with fibrous, flammable materials (i.e., fluff from clothes, tickets and other small litter, human hair, rat fur, etc.). A test was conducted where lit matches were dropped on the escalator to see if ignition would occur. The dropped matches ignited the contaminated grease, and the fire began spreading, which confirmed the initial eyewitness reports up to that point. But four expert witnesses could not agree as to how the small fire had flashed over, with some concern that the paint used on the ceiling had contributed to the fire.
A model of King’s Cross station was built at the Atomic Energy Research Establishment, and, using computer simulation software, they were able to show that the flames had laid down along the floor of the escalator rather than burning vertically before producing a jet of flame into the ticket hall. The end result matched the eyewitness accounts of the fire.
Experiments were conducted with a third-scale replica of the escalator built at the UK’s Health and Safety Executive site at Buxton. After seven-and-a-half minutes of normal burning, the flames laid down as they had in the computer simulation. The metal sides of the escalator served to contain the flames and direct the temperature ahead of the fire. When the wooden treads of the escalator flashed over, the size of the fire increased dramatically, and a sustained jet of flame was discharged from the escalator tunnel into the ticket hall. The 30° angle of the escalators was discovered to be crucial to the incident, and the large number of casualties in the fire was an indirect consequence of a fluid-flow phenomenon that was later named the “trench effect”—a phenomenon completely unknown before the November 1987 King’s Cross fire. The conclusion was that this newly discovered trench effect had caused the fire to flashover at 7:45 pm.
London Underground was strongly criticized in the report for their attitude to fires underground, underestimating the hazard because no one had died in a fire on the Underground before. Staff was complacent because there had never been a fatal fire in the Underground. Staff had little or no training to deal with fires or evacuation and were expected to send for the Fire Brigade only if the fire was out of control.
The Inquiry published its official report in November 1988, making 157 recommendations, including:
- Replacing wooden escalators
- The smoking ban extended to all station areas.
- Radio equipment used by British Transport Police to be compatible with those of the Brigade.
- A review of the Brigade’s Personal Protective Equipment (PPE).
- Improvement to the Brigade’s radio communications between firefighters below ground.
- Plans to be kept outside stations in locations agreed with the Brigade.
- Review of training and policy. (LFB, n.d.)
The After-Effects of the Disaster
The inquiry’s report led to resignations of senior management in both London Underground and London Regional Transport and to the introduction of new fire safety regulations. Wooden paneling was removed from escalators; heat detectors and sprinklers were fitted beneath escalators, and the radio communication system and station staff emergency training were improved. This tragic fire redefined policy on public transport and led to changes that keep everyone much safer today.
The Fire Precautions (Sub-surface Railway Stations) Regulations of 1989 were introduced. Smoking was banned in all London Underground stations, including on the escalators, on November 23, 1987, five days after the fire. As of 2014, the entire London Underground was operating on metal escalators, after the last wooden escalator at Greenford on the Central line was decommissioned on March 10, 2014.
The Inquiry’s report also recommended that London Underground investigate “passenger flow and congestion in stations and take remedial action.” Consequently, Parliamentary bills were tabled to permit London Underground to improve and expand the busiest and most congested stations. Since then, major tube stations have been upgraded and expanded to increase capacity and improve safety. The fire also led to improvement in firefighters’ equipment: yellow plastic leggings that melted in the heat and rubber gloves that limited movement were replaced with more effective protective apparel.
At Soho Fire Station, Station Officer Colin Townsley’s space remains empty in memory of him and the members of the public who lost their lives that terrible day. Six firemen received Certificates of Commendation for their actions at the fire, including Townsley, who was posthumously given that award as well as the George Medal.
This also highlights the importance of routine housekeeping to prevent the accumulation of trash and debris, specially in places where it can become contaminated with oil or grease.
Nice summary! Very thorough.
Another way to describe the so-called “trench effect” is that of a “favorable pressure gradient” which ensures the boundary layer remains attached to the underside of the sloped surface. The buoyancy force acting upward against gravity helps keep the boundary layer thin. In contrast, when a boundary layer’s thickness grows rapidly due to an “adverse pressure gradient”, it separates from the surface and a chaotic, turbulent wake is created, whose presence would obstruct and inhibit the upward flow of hot gas through the escalator tunnel.