On October 31, 1963, a gas explosion occurred at the Indiana State Fairgrounds Coliseum in Indianapolis, United States, killing 81 people and injuring about 400 others. It was one of the worst disasters in the history of the state.

On the night of October 31, over 4,000 people were in the coliseum to watch a Holiday on Ice performance. While this was happening, liquefied petroleum gas was leaking from a tank that was stored with several others in a supply room underneath a part of the grandstands. Shortly after 11 p.m. ET, the gas came into contact with an electrical heating element from the concessions area, causing a major explosion that killed many seated above the room and caused significant damage to the stands. After the initial blast, while people were evacuating, a second blast caused by the remaining, unexploded tanks resulted in further destruction. Firefighters and other emergency responders were at the site within minutes and survivors were transported via ambulance to various hospitals in the area. The gas tanks were discovered by firefighters during cleanup operations and later testing revealed that they were the cause of the explosion.

Following the disaster, a grand jury indicted seven people in total, including employees of the gas provider and the company that operated the arena, as well as the state fire marshal and the city fire chief. However, at later dates all of the individuals either had their charges dropped or their convictions overturned. Victims of the explosion were eventually awarded $4.6 million in settlements. Several city and state agencies investigated the explosion, and it was one of the first events studied by the Disaster Research Center, a research group organized earlier that year to study large-scale disasters. The arena reopened about six weeks after the incident and still stands on the Indiana State Fairgrounds.

Background

The Indiana State Fairgrounds Coliseum is a multi-use arena with a seating capacity of about 7,800 located on the Indiana State Fairgrounds in Indianapolis. On the night of October 31, 1963, 4,327 spectators were present at the arena to see the opening-night performance of Holiday on Ice. This was the first performance of the ice show's scheduled eleven-day run in Indianapolis, and the coliseum promoted it as part of its "Shriners Night". It had been raining throughout the night and, because it was Halloween, the Indianapolis Police Department (IPD) had activated more police officers than usual. The show had been scheduled to begin at 8:30 p.m. EST, but it had started about fifteen minutes behind schedule, and around 11 p.m., the finale was about to begin.

Explosion The explosion occurred at 11:06 p.m., during the show's finale. The explosion was centered on the southeastern end of the arena, just underneath the box seats of Aisle 13. The initial blast lifted approximately of floor and launched debris and spectators towards the ice rink. Shortly thereafter, a load-bearing wall underneath the stands gave way and caused an additional cave-in of about of floor. A few minutes after the initial blast, a smaller explosion occurred that produced a fireball that rose high. Both before and after this second blast, evacuations of the arena were underway, with the spectators mostly leaving in an orderly fashion. During the evacuation, the Holiday on Ice orchestra continued to play and reports of the evacuation make note that there was no significant mass panic, with many of the evacuees experiencing shock. The location of the explosions had left a crater measuring approximately across that contained a great deal of rubble and a small fire.

Emergency response

Within a minute of the first explosion, an off-duty firefighter who was in the audience telephoned the headquarters of the Indianapolis Fire Department (IFD) and informed them of the situation, immediately identifying the incident as a gas explosion. This call also alerted the IPD, as the dispatchers for the IFD and the IPD regularly monitored each other's calls. Very shortly after this call, another off-duty firefighter at the coliseum called the IFD and requested that ambulances be sent to the scene. As a result, in the first notification that any hospital received of the disaster, the dispatcher called a local hospital and requested that all three of their ambulances be sent to the arena. At 11:11 p.m., the IFD contacted the IPD directly to ensure that they were aware of the situation. A police car first arrived on the scene at 11:15 p.m., and additional cars were dispatched to the scene shortly thereafter. This initial police car radioed that an estimated 10 to 15 people had died. Around this time, additional crisis organizations in the area, such as The Salvation Army and the American Red Cross, were alerted to the situation and began to mobilize, sending some of their personnel to the coliseum to assist. Within nine minutes of the explosion, a photographer for local television station WFBM-TV was at the scene, and news of the event would be broadcast on the late-night news. The Indianapolis Star had over 40 employees work to have the story quickly added to the next morning's paper before the press deadline of 1:30 a.m.

At 11:23 p.m., a police car at the scene radioed a request for cranes and tow trucks to be sent to the arena. While the dispatcher notified them that all available tow trucks would be sent to the site, no further mention was made of sending cranes, and as much of the rubble in the arena needed to be lifted and not dragged, the trucks saw only minimal use. Around this same time, the first fire engine, which had been stationed near the entrance to the fairgrounds, arrived and began to put out the fire, with a firefighter on board giving an estimate that between 50 and 100 people had been injured. IFD dispatchers radioed the Indianapolis Fire Chief Arnold W. Phillips and called for an additional engine and rescue squad to go to the coliseum. The fire chief ordered that heavy equipment be brought in to help free some of the injured spectators from the rubble, as the firefighters' electric hacksaws had proved ineffective. Because the fairgrounds were state property, local police notified the Indiana State Police, who had been mobilized by Indiana Governor Matthew E. Welsh. The state police immediately sent three officers to the site. While initial estimates from the state police put the death toll at 12 to 15, that number continued to rise and more state police troopers were called in through the night.

The District Chief from the Office of Civil Defense's 5th District also arrived on the scene shortly after being notified by the IFD and requested both additional manpower and that all hospitals in the area be contacted and informed of the situation. In total, about 250 volunteers participated in the direct emergency response. Meanwhile, Civil Defense officials began sending their own emergency equipment, primarily focusing on tools that could remove the debris. Around 11:35 p.m., they contacted the police department of nearby Speedway, Indiana, and requested that they borrow a mobile crane from a local heavy equipment company. Speedway police responded shortly afterwards that the mobile crane was on its way via police escort, and it arrived at around 12:50 a.m. As the response efforts increased, traffic quickly became a problem as more vehicles arrived to bring emergency equipment, with ambulances being hindered in their ability to remove injured people from the site. As a result, Civil Defense officials began directing ambulances to enter the fairgrounds on the north side and exit to the west. As more injured people were removed from the coliseum, the west field of the fairgrounds became a makeshift triage center. Civil Defense officials began directing some ambulances to take their injured to a nearby military base to avoid possibly overcrowding local hospitals. U.S. Army ambulances from this facility were also deployed.

By 11:30 p.m., only 10 injured people remained in the arena. The Marion County Coroner arrived at the scene at 11:45 p.m. and was one of the first physicians present. Due to the large number of victims, the coroner established a temporary morgue on a sectioned-off part of the ice. About five minutes after the coroner arrived, the Indianapolis chief of police arrived and set about establishing a command post in a building near the fairgrounds. This post was in place by midnight and was led by five individuals: the Marion County sheriff, the police chief, the county coroner, the director of civil defense, and a representative from the state police. By midnight, almost all of the injured people who were not trapped under rubble had been taken outside of the coliseum. Shortly after midnight, the superintendent of the Indiana State Police, as well as the Salvation Army's canteen truck and nurses from the American Red Cross Motor Corps, arrived at the fairgrounds.

As cleanup efforts continued into the early morning of November 1, five liquefied petroleum gas (LP gas) tanks were discovered in the wreckage and were moved to the Fire Headquarters for inspection. By 1 a.m., all wounded individuals had been removed from the site and were being treated in hospitals around the area. At 1:47 a.m., the police chief, attempting to reduce traffic congestion around the arena, barred any additional vehicles from entering the fairgrounds. About 15 minutes later, at 2 a.m., the police chief called a meeting of the command post to outline the process for body identification. At the time, only 21 bodies had been identified from the wreckage, and the police had a team of four ministers and priests to contact the deceased's next of kin. Around the same time, it was decided that the command of the situation would be gradually handed over from the chief of police to the Indiana State Police, as the fairgrounds were state property. At about 3 a.m., some relatives of those thought to be dead from the explosion began to arrive to identify their bodies, and half an hour later, a press conference was held wherein the command post gave updates about the state of the response and answered some questions regarding the cause of the incident. At 6:30 a.m., the IPD handed over control of the site to the State Police and, save for those who were assisting the coroner, most IPD officers left the site. At this point, most of the emergency tasks at the site had been completed. By 3 p.m., all but two of the deceased had been identified, and shortly thereafter, the coroner ordered that the remaining two be moved to a nearby hospital and that the coliseum be closed. By 4 p.m., the coliseum was almost entirely vacated, except for State Police officers who were stationed at the entrances.

Aftermath Severity of the disaster The explosion was one of the worst disasters in both Indianapolis and Indiana history. Approximately 54 people died in the initial explosion, and others later succumbed to their injuries, raising the number of fatalities to approximately 81. Among the dead was a former mayor of nearby Lafayette, Indiana. The 1963 coliseum explosion became the deadliest in Indianapolis's history, surpassing an 1869 boiler explosion that had killed 30 people. Coincidentally, this previous explosion had also occurred at the Indiana State Fairgrounds. According to a 1968 case study, the explosion was also "the highest single death toll ever to occur in an Indiana disaster". In addition to the fatalities, approximately 400 people were injured. A later statement from the Marion County Sheriff's Department projected that had the performance begun on time, there would not have been as many casualties. It took until October 30, 1964, for the last person who had been injured in the explosion to be released from the hospital. A memorial service was held the following day for the victims of the explosion on the event's one-year anniversary.