Paceville Stampede - A scientific background to the case

P ACEVILLE STAMPEDE – A SCIENTIFIC BACKGROUND TO THE CASE 74 people were injured as a result of a stampede, which occurred last month. The probable causation of the stampede is the sudden overcrowding in a relatively small area, instigated when a man allegedly sprayed pepper or gas spray inside the premises.

A stampede is initiated when people push tightly against each other in a confined space. A recent crowd management study suggests that during a stampede, 7 people end up in an area of 10 square feet. It is therefore imperative that in such instances, the individuals involved aim in maintaining the flow of passage. Failure of this will ultimately result in crushes. Crushes typically occur when members at the back of a large crowd continue pushing forward not knowing that those in front or at the sides are impeded by some force of hindrance. It is calculated that a crowd of only 6 to 7 people can exert a force of around 6,900kPa, the equivalent pressure able to cause the collapse of a brick wall.

In stampedes shortness of breath is a common consequence, however during this event this was predominantly augmented due to the reported use of pepper spray inside the complex. Pepper spray is commercially available and usually comes in an aerosol can. The active ingredient oleoresin capsicum (OC), is an oily substance extracted from chili peppers which when mixed with a propellant, may be dispersed to target a wide area. Typical pepper sprays measure between 500,000 and 5,000,000 SHU, (Scoville Heat Units, a heat scale used to rate heat levels in peppers.) When relative to the 8,000 SHU of a jalapeĂąo pepper, the intense irritation may be approximated.

Upon exposure to the spray, the immediate burning sensation of the eyes, nose and throat is sensed and once inhaled, the swelling of throat and eyes follows. Consequently, difficulty in breathing and simultaneous temporary blindness is experienced.

The instilled physiological effect like the fear of the unknown, panic and anxiety can further lead to hyperventilation and temporary increase in blood pressure.

When coming in contact with this type of chemical, the first thing one has to do is to find a way to be in a space of fresh air. If in a complex, this is done by means of accessible emergency exits that should be easily noted and distributed evenly within the complex. It is important that these emergency exits are notable to people when they enter the complex. This is of great help in times of chaos since if the people trapped in the complex know from beforehand where they need to go to escape the danger, panic and anxiety are reduced as one already knows what he needs to do.

Consequently, the danger created from fear and panic is also greatly reduced and so the number of potential victims is decreased. A problem encountered in this event was that the emergency exits present in the complex lead to the neighbouring clubs, this is not even an emergency exit since if chaos is present in the neighbouring clubs, one cannot exit the complex easily. An emergency exit should be strategically located outward opening door with a crash bar on it and with exit signs leading to it. This is necessary in crowded locations and the complex should have had a proper emergency exit.

From this incident we can conclude that the complex was not well equipped for this kind of incident. Such regulations should have been taken beforehand and this could have been easily prevented if the structure of the building was well planned and the members of staff were well trained.

We would like to thank Maria Falzon for her help on the report and Pamela Cuschieri for proofreading.