Grain is the most common food item in most American diets. Whether the grain is corn, barley, wheat, or something more exotic, transporting it from the farm to the dining room table is a massive undertaking by any standard of measurement – and includes many stops along the way – the first of which, usually, is a massive grain silo.
There are three principal risks involved in the operation of silos: entrapment, the possible presence of toxic gas, and various mechanical hazards. The ability to plan for and carry out a successful grain-silo rescue, however, requires: (a) a highly specialized skill set and the use of equipment that is usually not available on standard fire or rescue units; and (b) a unique combination of confined-space maneuvers and specially designed entrapment/extrication gear.
Modern silos are much more than simple albeit outsized storage cylinders. Today’s typical silo is fitted, for example, with at least one large auger, positioned at the bottom of the silo, to facilitate the movement of grain from the silo to a truck or train car. The auger is specifically designed to draw grain from the bottom of the silo and, by doing so, let gravity push the grain above further down in the silo. However, this same self-feeding arrangement also creates a steady flow of grain, in large quantities, that can easily create a “quicksand” effect for anyone inside the silo who is standing on top of the grain.
Harnesses, Rescue Tubes & Breathing Apparatus
To mount a grain-silo rescue, the first priority, of course, is the safety of the rescuer(s); harnesses are a must and respiratory precautions should be used as needed. Preventing the grain from crushing the person being rescued is the next priority. That person also should be harnessed as quickly as possible; at the same time, the power to the auger (and any other equipment in the silo) should be disconnected to prevent the victim from being drawn even deeper into the grain.
To maintain an open airway to the person trapped inside the silo, rescuers must clear the grain as quickly as possible from around that person’s face and upper body. A five-gallon plastic bucket, with the bottom cut out – or a commercial rescue tube – can be placed over the victim’s head. Because the grain in the silo consists almost entirely of dry particles, simple shop vacuums can be used to remove any grain inside the tube or bucket.
The bucket and/or rescue tube both serve the same purpose: to keep the grain from filling in and clogging the breathing space being cleared by the rescuers. Without such barriers, the grain would naturally collapse, like a flow of sand, into the space being cleared.
As is true of almost any other confined spaces, the air in a silo can become a hazard in itself by building up potentially toxic gases and/or explosive powder – created by fermentation of the grain itself – or by decreasing the volume of oxygen in the air. In fact, according to the U.S. Department of Labor’s Occupational Safety & Health Administration, there were 503 grain-elevator explosions in silos throughout the United States in the period from 1976 to 2011.
Fortunately, there are now some high-tech systems available for testing the gas inside silos, particularly for oxygen content and contaminants. In addition, depending on the specific hazardous conditions involved, respiratory protection systems for the rescuer(s) as well as the victim also are available. Powered Air Purifying Respirators (PAPRs) and Self-Contained Breathing Apparatus (SCBAs) are the systems most commonly used.
Avoiding Dangers, Risks & Hazards
The mechanical gears and systems used to move the grain into and out of silos also can be dangerous. As with many other types of machines, human arms, legs, and/or other body parts can quickly and easily become entangled in the moving parts of the equipment. In an entanglement situation, the safety of the rescuer must be the highest priority. It also is important to fully understand the type of equipment involved and its moving parts because energy can often become trapped when equipment is obstructed, but then quickly released while the victim is being disentangled.
As with other types of risks and hazards, prevention is almost always the best, least complicated, and least expensive strategy. Any person who enters a silo must be both: (a) fully trained in the safe methods of doing so; and (b) wearing or carrying the safety equipment required. Moreover, to fully and properly prepare for that unfortunate day when “things” suddenly go wrong, there is a continuing need for specialized rescue services, specifically including well-trained rescue personnel and the equipment they need for dealing with this unique but nonetheless dangerous hazard.
Joseph Cahill
Joseph Cahill is the director of medicolegal investigations for the Massachusetts Office of the Chief Medical Examiner. He previously served as exercise and training coordinator for the Massachusetts Department of Public Health and as emergency planner in the Westchester County (N.Y.) Office of Emergency Management. He also served for five years as citywide advanced life support (ALS) coordinator for the FDNY – Bureau of EMS. Before that, he was the department’s Division 6 ALS coordinator, covering the South Bronx and Harlem. He also served on the faculty of the Westchester County Community College’s paramedic program and has been a frequent guest lecturer for the U.S. Secret Service, the FDNY EMS Academy, and Montefiore Hospital.
