Seconds to React

Combatting grain engulfment accidents with proper equipment, procedures and training.
By Chris Hanson | August 12, 2013

Grain storage safety is a top-priority issue for ethanol producers such as Highwater Ethanol LLC. “One thing I tell my employees,” says Brian Kletscher, CEO, “is if there is any question at all if an employee should be doing something, they need to stop and talk it over and go through it. We don’t want to have to call their family and tell them there has been an accident at Highwater. We want them to go home the same way they showed up to work that day.”

 Grain engulfment is currently the leading cause of death inside grain bins, and the U.S. Occupational Safety and Health Organization reports the number of incidents has increased, doubling between 2006 and 2010. More recent studies, including one completed by Bill Field, a professor at Purdue University, found that in 2011 no fewer than 30 incidents across farms and commercial grain handling facilities were reported. 

 The good news, however is, more thorough safety procedures, first responder training and expanded public awareness of grain engulfment are having a positive impact. Field’s research found that in 2011, the ratio of fatal-to-nonfatal incidents decreased 69 percent. By 2012, the number of documented entrapments had dropped to 19, a 37 percent decrease from the year before.

 Engulfment can occur in one of three ways. One scenario involves a person standing on the surface of flowing grain inside a silo. Once the grain begins flowing, the worker has roughly four seconds to react before he or she becomes completely immobilized by the surrounding material. Within 22 seconds, the person can become completely covered.

 The most common engulfment situation occurs when workers attempt to loosen grain that has crusted and bridged, restricting the flow of grain. Bridging can occur when grain has more than 15 percent moisture content or mold causes grain to begin spoiling and clumping, forming a crust that stretches across a bin, Kletscher says. Underneath the crust lie potential voids, especially if the bin has been partially emptied. These can unexpectedly collapse beneath a worker, trapping him in seconds.

 Field found in his research that the primary cause of entrapment situations in 2011 was victims trying to dislodge crusted grain while the unloading equipment was running. Similarly, dislodging steep piles of grain along the sides of a bin can trigger avalanches and bury unsuspecting workers.

 Once engulfed, the trapped person experiences what is described as being squeezed by a constrictor. Glenn Pribbenow, director of the Kansas Fire and Rescue Training Institute from the University of Kansas’ Continuing Education program, explains that with each exhale, the surrounding material fills in the space around the chest and prevents lungs inhaling to their full capacity, leading to suffocation. 

Equipment and Procedures
 Engulfment scenarios can be frightening to consider for any plant with onsite storage. However, providing adequate safety equipment and better first responder training and enforcing OSHA-approved practices are just a few of the ways engulfment dangers are being addressed.

 The OSHA safety standard for grain handling requires that employers provide annual training and specific procedures to guarantee a safe work environment. Shane Rasset, a safety manager at Highwater Ethanol, agrees that training is crucial. “I’d say that either lack of training or lack of hazard information would probably be one of the big reasons why accidents happen,” he says.

 Before a person can enter a grain storage bin, an employer must ensure all mechanical, electrical, hydraulic and pneumatic equipment that may pose a threat are de-energized, disconnected or prevented from accidental operation. Next, the environment inside the bin must be tested for combustible gases and oxygen content. If the oxygen content does not meet a 19.5 percent threshold, respirators are required. Ventilation is mandatory if the environment contains more than 10 percent combustible gas. Additionally, the employer has to ensure the entering worker will not be walking down grain to make it flow or entering underneath bridging grain, practices that are prohibited by OSHA. Once those criteria are met, the employer may permit a worker to enter.

 “Inside a grain storage bin, it can be very dangerous,” Kletscher says. “We, generally, would not allow anybody to go inside the grain bin unless they’re completely tied off and can be winched out.” The company prefers that no one enter the bin at all, he says.

 If there is sufficient grain that may pose an engulfment hazard, the agency requires a worker to be equipped with a body harness with a lifeline or utilize a boatswain’s chair to ensure the employee will not sink any deeper than the waist. At Highwater, a worker will use a tripod to lower another worker through the top in order to clear grain that may have accumulated along the bin walls.

 In addition to the safety equipment, a second employee acts as a point of contact for the bin worker. This observer maintains a line of communication with the person in the bin and is trained in rescue operations. Therefore, if an incident were to occur, the observer can assist in digging out the worker from waist-deep grain or call for help, if needed.  Kletscher says Highwater’s observers are equipped with two-way radios to maintain contact with both the person in the bin and the control room. He adds the company’s safety manager is in the vicinity as well. 

Rescue Training
 Even when adequate safety equipment and training are provided, accidents can still occur. Therefore, OSHA requires facilities to have suitable rescue equipment on hand. Some first responders and grain industry employers are developing emergency response equipment and training classes, such as the grain engulfment rescue training program developed last winter by the KFRTI. Pribbenow explains the class was created after the institute was approached by a group that was trying to meet grain rescue training needs. The group included the Kansas Cooperative Council, Kansas Grain and Feed Association and the Kansas Farmers Service Association.

 The one-day class acts as a beginner’s course in addressing the most common rescue methods and the lengthy task of rescuing a person in an engulfment situation. Pribbenow explains the first half of the training day focuses on OSHA regulations, prevention and grain bin rescue procedures and practices. During the afternoon session, the class then practices with KFRTI’s 35-foot rescue trailer, which was developed to simulate engulfment rescue scenarios.

 Created around the same time as the class, the trailer contains a grain bin, hopper and storage compartments for tools and materials. Once assembled, the class learns and then demonstrates rescue methods and bin cutting techniques in an open-top hopper and models used for cutting. Afterward, they apply their knowledge at a larger, closed-top bin to simulate the tighter conditions that occur in real-life scenarios. In addition to playing the role of rescuers, Pribbenow says the students also play victims by becoming engulfed up to their waists. This makes the students more empathetic to the victims by understanding how difficult it is to escape those conditions.

 Rescue methods to extract an engulfment victim are not a quick process. Pribbenow explains rescuers cannot simply pull a victim from the grain. He says to pull someone buried chest-deep in grain would require 1,200 to 1,400 pounds of force, which would cause serious harm to the victim’s body. Therefore, the most common rescue method is to use coffer dams to dig a victim out.

 The coffer dams form a perimeter around the victim and can be made of almost any material, from a repurposed 55-gallon drum to special interlocking, aluminum walls.  The rescue tubes used by KFRTI are from Missouri-based KC Supply Co. Inc.Jeff Lavery, owner of KC Supply, explains the tubes are first lowered into the bin in either four or six sections, depending on the size of the opening. The first section is placed perpendicular on the uphill slope of the grain to prevent more material from sliding down and burying the victim even further. Next, the other sides of the tube are slid into the grain, interlocking with the first piece. After the tube is assembled, rescuers may start excavating the grain inside the tube to relieve pressure on the victim. He adds the bottom of the tube initially only goes 18 inches beneath the grain’s surface; therefore, it can be pushed down using external handles to gradually move the tube downwards as more grain is removed around the victim. Lastly, once the pressure is decreased enough, rescuers can help the victim out of the grain for medical treatment. 

Author: Chris Hanson
Staff Writer, Ethanol Producer Magazine