Preventable deaths in the workplace happen around the world every day. They rarely make front-page news, even when they have important lessons we could learn to avoid them in the future. However, the deaths of eight people at a Houston music festival on November 5, 2021 have cast the spotlight on how multiple, seemingly minor factors can aggregate within a system and culminate in a tragedy that could have been avoided with better planning and more insightful risk management.
Tragedies involving large crowds and poor planning have a long history. Despite the fact that event organizers often seem not to have learned from these disasters, there are several factors we might recognize in common with other similar events. Here’s a brief review of some of the most significant crowd disasters in recent history.
On December 3, 1979, the British rock band The Who was scheduled to perform at Riverfront Coliseum in Cincinnati, Ohio. Organizers used a system called festival seating, meaning there was no assigned seating and people were free to arrange themselves in the open space as they liked. Prior to showtime, thousands of fans gathered outside the stadium in front of a series of doors that would provide entry. However, when it came time to admit people into the venue, officials opened only two of the several doors available. When the crowd surged towards these two doors, a bottleneck formed, with people at the back pushing forward to get into the arena. Many people who fell during this rush were trampled, while others at the front succumbed to asphyxiation from the pressure of the thousands of people behind them. 11 people were killed, six of them teenagers.
Hillsborough, UK, 1989
On April 15, 1989, in Sheffield, England, another crowd bottleneck resulted in one of the most significant tragedies in British sports. During a soccer match between Liverpool and Nottingham Forest, a huge crowd of supporters created overcrowding near the main turnstiles outside the stadium. In an attempt to ease the pressure of the crowd, police ordered a single exit gate be opened to allow supporters into the stadium. Those supporters ended up trapped in enclosed pens, with more people pouring through the turnstiles behind them. The result was a massive crowd that quickly asphyxiated the people trapped by the fences at the front of the pens. 96 people were killed and 766 were injured.
Station Nightclub: 2003
On February 20, 2003, a fire ignited by stage pyrotechnics resulted in the deaths of 100 people and 230 injuries at The Station night club in Rhode Island. The pyrotechnics ignited the foam insulation surrounding the stage. According to the official accident report, it took less than a minute for smoke to fill the nightclub and five minutes for flames to break through the roof. The panicked crowd was unable to access any of the four fire exits beside the stage, which forced over 400 people into the narrow hallway at the entrance as they tried to flee. Most of the deaths occurred from burns and smoke inhalation when that exit quickly clogged and prevented people from leaving the building.
During a music festival in Denmark on June 30, 2000, a crowd crush formed at the front of the stage. The audience of 50,000 surged forward during a performance, forcing many people to fall to the ground. When people fell, the space they had occupied was quickly filled by other people rushing towards the stage. Nine people were killed by asphyxiation and 26 were injured.
Love Parade, 2010
Love Parade was an electronic music festival in Duisburg, Germany. On July 24, 2010, 21 people were killed and more than 500 people were injured when crowds found themselves trapped in a tunnel entrance with no point of egress. In contrast to some other incidents, in which panicked crowds rush towards a single entrance, the root cause of this disaster was a phenomenon called crowd turbulence. Crowd turbulence occurs when crowd density hits seven people per square meter. At this point, the crowd begins to take on the properties of a fluid, in which even small individual movements are transferred and amplified through the mass. Individuals can be lifted off the ground and carried by the fluid that no longer has any individual agency, but which will continue to fluctuate and cause turbulence as long as the density remains consistent or increases. Most of the fatalities were the result of asphyxiation, as the crowd became so dense as to restrict the ability of individuals to expand their ribcages to breathe properly. Failure to regulate the flow of people through confined spaces was a direct cause of this disaster.
Common Factors in Crowd Disasters
Disasters rarely have single causes. Instead, smaller events aggregate over time and amplify one another before catastrophe occurs. Most disasters are also, for the most part, predictable, and could be prevented by applying the lessons learned in previous events. Here are a few common elements in some of the crowd-related disasters described above.
Festival seating is present in the vast majority of crowd-related disasters. A lack of assigned space for audience members means people compete for space to get the best vantage point of the show, resulting in crazed behavior motivated by excitement. By the time crowd density reaches seven people per meter, crowd turbulence begins to take over and people have about as much control over their actions as they would being tossed around in rough ocean waves. Festival seating creates an uncontrolled and potentially uncontrollable environment in which the people caught in it have no situational awareness and no obvious point of egress.
Limited Points of Ingress and Egress
Most crowd disasters involve limited points of ingress (entry) and exit (egress), which creates deadly bottlenecks as the pressure of excited crowds forces people to attempt to push their way through, resulting in people in the bottleneck falling and being crushed or asphyxiated by the surging crowd. Most spaces have not been designed to handle the flow of thousands of people, and they frequently function beyond the specifications of their intended design.
Within the crowd, communication is limited to small cells consisting of only a few people who are close enough to one another to speak. Cells overlap and can communicate to one another, but often only to spread panic and misinformation. These cells usually cannot communicate backwards, which means the people at the rear pushing forward do not receive communications from the people at the front. Further, people at the back often misinterpret forward momentum as progress, despite the fact that it is the result of people at the front being crushed or falling to the ground. Communication between audience members and authorities is critical, as is the ability of the authorities to communicate easily with one another.
Poor Crowd Management
Although the terms are often used as synonyms, crowd management and crowd control are not the same thing. Crowd control is based on restricting the behavior of crowds by the use of force, as in, for example, a riot. Crowd management, on the other hand, is based on planning for large crowds, facilitating their movement through passageways to the final gathering place and managing crowd density throughout the event. It involves understanding the space being used, points of ingress and egress, group behavior and access for emergency services. In many situations, crowd disasters are the result of poor crowd management.
Poor Training and Emergency Response
Many workers at large events are causal labor. In many cases, they have no training in crowd management or emergency response and have no situational awareness to respond to crowd threats. They have no established emergency or communications plans and view their jobs simply as crowd control. It usually takes very little to overwhelm their ability to respond to dangerous situations involving thousands of people.
Important Lessons from Crowd Disasters
Crowd-related disasters are particularly poignant tragedies. The victims are ordinary people at an event at which they’re hoping to enjoy themselves. Very rarely is any malice involved.
However, there are important lessons we can learn from these disasters to keep people safe in other kinds of situations.
Systems Thinking is Critical for Avoiding Disasters
Many people think that disasters are Black Swan events that simply come out of thin air and take everyone by surprise. In reality, they are often a cascading series of smaller failures that aggregate and are amplified by failures to prepare for them. Disasters are often the result of not understanding complex systems and the interaction of interconnected elements that represent critical points of failure. At an event, this means that everything from the integrity of ticket sales to training security people to the design of the venue.
In other situations, disaster can be the culmination of a potent brew of elements like poor documentation, inadequate safety or quality culture, inefficient communication, competing priorities, prioritizing profit or lax regulatory oversight. Disasters such as those involving the Space Shuttle Challenger, the Boeing 737 MAX and the Deepwater Horizon demonstrate that critical failures rarely appear out of nowhere. Instead, they provide seemingly minor leading indicators that accumulate over time. A perspective informed by systems thinking and a culture of safety and quality can help provide insight into how to create resilient systems that can withstand stress and avoid catastrophe.
Risk is Everywhere
Most people don’t understand risk. Many organizations don’t either. Threats and opportunities are rampant in complex systems, especially those that feature dynamic environments with many uncontrolled elements, such as large-crowd events. Risk mitigation strategies often focus on high-probability/low-impact events that can be easily predicted, but they neglect low-probability/high-impact events. Crowd-related disasters aren’t common, but nor are they rare. They are frequent enough that practitioners in crowd management know how to mitigate that risk and avoid disaster while taking advantage of opportunities to create better audience experiences and engage in continual improvement of best practices. However, when leadership prioritizes profit or exposure over safety and risk management, the likelihood of disaster increases exponentially.
Most disasters aren’t inevitable. Tools, processes and expertise exist that can provide the insight required to avoid them. Each time a disaster that claims human lives takes place, it produces copious amounts of data and opportunities to learn how to avoid it next time. Crowd-related disasters like the one in Houston are examples of something that could easily have been avoided with proper preparation and risk awareness.