Ergonomics in Disaster Response

Here In Minnesota, we receive daily reminders of the threat for ‘imminent, state-wide flooding’ this spring. In the past few days, tornadoes have damaged several southern US cities, and a volcano has erupted in Hawaii. Earthquakes devastated portions of New Zealand, Chile, and Haiti in the past 14 months, and the list goes on. 

So what does ergonomics have to do with disasters?

First, a few definitions. In the US, we refer to events such as house fires, automobile collisions, heart attacks, etc., as ‘emergencies’. These are situations where trained workers must respond quickly in order to protect lives, safety, or property. Because emergencies happen on a regular basis it is possible to evaluate tasks and to design tools, methods, and equipment to help these workers, in a manner similar to that for tasks performed in other work environments.

Examples of ergonomically advantageous gear for firefighters, for example, include lighter weight self-contained-breathing-apparatus (SCBA), which reduces the load they must carry while performing other tasks; and the ‘Jaws of Life’, which provide tremendous leverage for extrication tasks in a relatively light, flexible, and maneuverable format.

‘Disasters’, on the other hand, are defined as events that overwhelm the local ability to respond. This definition implies that needs will exceed the number of trained responders and the supply of specialty equipment designed for emergencies. 

Recent flooding in Australia, for example, was described by news media as covering a land area larger than the countries of France and Germany combined.  While some shortfalls can be tempered by mutual aid agreements and stockpiles, large scale or widespread disasters create special challenges for those who do respond, including volunteers and un-trained Samaritans.

A key constraint in disaster response is the uncontrolled nature of the work environment. Although, ergonomists working with building trades comment on the perpetually changing environment at a construction site, that progression is intentional, predictable, and controlled. Emergency workers often face unique circumstances with vehicle and industrial incidents; however, those typically involve a localized situation within a functioning support system.

In a disaster environment, workers may face the lack of electrical power, water, fuel, and basic supplies over a widespread area.  Communication and coordination of efforts may be difficult, and even roads or road signs may be destroyed making access or transportation of equipment difficult.

In these situations, it helps to focus on basics. Rather than thinking of ergonomics as a high level analysis, or optimization of workers’ interaction with tools, tasks, equipment, and work environments, basic principles, such as keeping a load close to the worker, and administrative controls, such as training, or dividing a heavy task among many workers, often provide accessible options when engineering controls are simply unavailable.

Disaster response work encompasses many tasks: search and rescue, debris removal, communications, feeding and sheltering, etc.; each with its own set of opportunities and challenges, depending upon the situation. For this discussion, I will use the ubiquitous sand bag for illustration.

Sandbags are a basic commodity in flood fights. The US Army Corps of Engineers (USACE) estimates that a 3 foot high dike requires 3,600 sandbags for each 100 foot length of dike. News reports indicate that some communities in Minnesota and North Dakota will prepare 3 million sandbags each to protect against floodwaters this spring – a monumental material handling task measured against any metric. While pallets, fork trucks, and construction machinery are used to transport sandbags wherever possible, final placement is by hand to insure effective dike construction.

One simple administrative control is to only fill the mesh bags part way, resulting in an easier to lift and carry weight of approximately 30 – 40 pounds, instead of 60 – 75 pounds for a full bag.  It is counter-intuitive for motivated volunteers to ‘under fill’ a bag.  Yet from an engineering perspective, and consistent with USACE recommendations, not only are the partially filled-bags easier to lift and carry, the flaccid bags pack into a tighter and more effective dike than bulging bags: a win-win situation.

Placement of sandbags is another opportunity for administrative controls. While motivated volunteers can lift, twist, throw, catch, and place sandbags for a while, few can sustain those activities for the extended hours or consecutive work days of flood work.  Workers who become sore or injured disrupt the response work, just as they do in a conventional workplace.

Another administrative approach is to use additional workers for sandbag transfer (‘many hands makes for light work’).  Workers packed shoulder to shoulder, in 2, parallel, facing lines allows 3 to 4 sets of hands to be maintained under each sandbag, forming a human conveyor belt, allowing the work to be sustained.

Clearly, there are enormous opportunities to design, develop, and supply tools and equipment for disaster responders. There are also huge challenges when working unpredictable events and in uncontrolled environments. Immediate responses may require the use of administrative controls or method changes to reduce the risks of injuries or to improve effective task performance, even when less than optimal. 

Training, breaks, worker selection, and increasing staffing may be a big change from those of us focused on engineering controls. The fundamental principle of analyzing the interaction between people and the work they do remains.

This article originally appeared in The Ergonomics Report™ on 2011-03-08.