Flowing grain behaves like quicksand.
Grain exerts forces of friction and pressure on a person that prevent self-escape.
Grain engulfment and entrapment incidents are on the rise in recent years due to record harvests, larger storage facilities, and equipment that moves grain at faster rates than ever.
Activities associated with grain handling and storage pose a variety of risks to safety and health of workers, including entrapment and suffocation in grain, falls from structures or catwalks, entanglement in grain moving machinery, toxic atmospheres, electrocution, and dust explosions. This page addresses grain engulfment and entrapment hazards.
Grain engulfment has been a recognized hazard for decades. Yet both experienced and inexperienced workers continue to underestimate deadly risks associated with the speed and force of flowing or shifting grain.
Anyone who enters a storage structure containing grain, or who climbs onto an outdoor grain storage pile, is at risk of being entrapped or engulfed in grain. Fatalities have occurred in as little as a few feet of grain.
Roughly half of known entrapments occur on farms, and half occur in commercial facilities. Most entrapment and engulfment events occur because workers enter a bin or storage structure to check on condition of grain or to address problems with grain flow due to spoiled grain or equipment malfunction. But other scenarios present risks even when grain is not being unloaded from the structure.
Around 80% of reported engulfments involve a person inside a bin or storage structure when grain-unloading equipment is running. Engulfments in flowing grain also occur in outdoor grain storage piles, grain wagons, rail cars, and semi-trailers that unload from the bottom.
As unloading conveyors or augers remove grain through the bottom outlet, a funnel-shaped flow develops on the surface of the grain. Anyone standing on the surface while grain is being removed from below is at risk of being rapidly pulled down toward the outlet in the column of flowing grain. Submersion takes only seconds and once it begins, the pressure and friction forces of grain on the body are virtually impossible for victim to overcome. If grain unloading equipment is not shut off, victims can be pulled down into the unloading conveyor, auger, or sump.
Victims covered in grain are not likely to survive. Cause of death is usually asphyxiation.
Spoiled or “out-of-condition” grain clumps together and can develop a crust on the top surface. This crust appears solid, but it is unstable and may hide open voids below that develop as grain is removed. Bridged grain can collapse under a person’s weight, resulting in the victim being buried by falling and shifting grain. If unloading equipment is running at the time this occurs, the victim can be rapidly pulled down toward the bottom of the bin.
Spoiled grain can form a clumped mass that adheres to the vertical wall of a bin. Entering a bin to dislodge a vertical wall of grain that is higher than the victim is dangerous because the grain wall can suddenly break loose and fall like an avalanche, burying or injuring the victim.
Some fatal engulfments have occurred while individuals were using grain vacuums to remove grain from bins. When the grain vacuum nozzle is placed below the grain surface, a funnel flow of grain develops as grain is sucked into the tube. An operator can be pulled into the downward flow of grain if this nozzle is released or becomes buried below the grain surface near the operator’s feet.
Maneuvering the vacuum tube can be awkward, increasing the operator’s risk of slipping or losing balance as he tries to reposition the hose in flowing grain. If the operator falls or struggles for position, his movements can trigger an avalanche of grain if the slope of grain (“angle of repose”) is steep.
The best ways to prevent engulfment incidents are to eliminate the reasons for entering a bin in the first place, and to restrict unauthorized access by youth or other individuals who may be unaware of hazards.
The most common reason victims enter bins is to address problems associated with spoiled grain. Spoiled grain forms solid masses, crusts, and horizontal grain bridges and vertical grain walls that can collapse. Spoiled grain plugs augers and conveyors, necessitating entry into the structure to unplug or free the clogged equipment. To reduce the likelihood of grain spoilage,
If clumps or crusts develop in the grain, use a pole from outside the bin to probe or knock the clump free.
Post signage and lock access doors so unauthorized persons, bystanders, and youth cannot enter.
Post signage at all entry points to bins, outdoor storage piles, and other storage structures that
Train workers on grain storage hazards and risks involved with entering a grain storage bin or facility. Training should include recognizing grain quality problems, entry procedures, use of safety equipment, and emergency response, before allowing access to a bin or storage structure. Training should be provided at regular intervals, not just upon hiring or once a year.
The plan should include having cell phones on site, emergency numbers posted for local emergency responders trained in bin rescue, and prevention of untrained “would-be rescuers” who could increase grain pressure on a victim or even become engulfed themselves.
If mechanical and pneumatic grain moving equipment cannot be locked out, do not enter.
Use a gas meter to check for adequate oxygen content in the bin and the presence of toxic gases like carbon monoxide (which can be present if there is combustion or smoldering grain), fumigants, or excessive carbon dioxide.
If the air in the bin smells like spoiled or moldy grain, assume there are dangerous bridges or vertical grain walls that can collapse.
If grain is out of condition, or the atmosphere conditions cannot be determined, do not enter.
|Do not enter if:|
|Oxygen level||< 19.5% or > 23.5%|
|Carbon monoxide||> 25 ppm|
|> 10 ppm
> 0.3 ppm
smoldering/burning odors are detected
|Dust||Vision is obscured to < 5 feet|
A grain wall can collapse or a high slope of grain can shift suddenly, burying the entrant.
Never enter a bin
Two outside observers must be present to monitor entry and assist by regulating a lifeline tether.
One attendant must maintain constant visual monitoring of the entrant and have a system of communication worked out before entry (hand signals).
This consists of a full body harness attached to an anchored line, and limits the distance the entrant can drop or fall in the event that grain shifts or a grain bridge collapses beneath the entrant. The lifeline must be secured to a sidewall anchor (not the interior ladder) or a fixed point outside the bin to prevent the entrant from sinking more than waist deep into grain. One attendant monitors the feed of the lifeline to the entrant.
Grain Bin Entrapments.
A 51-minute radio program broadcast August 13, 2013 on the Illinois Public Media program “Focus”. will am 580 npr. http://will.illinois.edu/focus/player/grain-bin-entrapments
Grain Bin Safety.
A 17-minute YouTube video with explanation of scenarios resulting in grain engulfment hazards in storage structures, grain management to prevent conditions requiring entry of storage facilities, requirements that must be in place if entry must be conducted, and guidelines for managers to protect employees. Other grain safety hazards are also briefly discussed. Produced by Oklahoma State University Division of Agricultural Sciences and Natural Resources Stored Products Research and Education Center. 2011. http://www.youtube.com/watch?v=DQSqWbn-3X0
Buried in Grain.
A special series investigation by National Public Radio and the Center for Public Integrity examining the danger and weak regulatory response of grain bin entrapments. 2013. http://www.npr.org/series/174755100/buried-in-grain
Grain Bin Safety.
A 13-minute YouTube video produced by the National Corn Growers Association and the National Grain and Feed Foundation describing Illinois grain engulfment fatalities involving teenagers that occurred in 2011. http://www.youtube.com/watch?v=YDwJCdjlZYE&feature=youtu.be
Safe Grain Bin Entry.
A PowerPoint presentation by Georgia Tech Research Institute on safe entry techniques and permit use. www.oshainfo.gatech.edu/grain/module2-slides.ppt
For information on training in your area, contact:
You Can Die in a Grain Bin in Less Than 60 Seconds. (Work in Progress) The Official Blog of the US Department of Labor. 2013. http://social.dol.gov/blog/you-can-die-in-a-grain-bin-in-less-than-60-seconds/
OSHA’s Grain Handling Safety Website. https://www.osha.gov/SLTC/grainhandling/index.html
Entrapment Risk due to Flowing Grain. Farm and Ranch eXtension in Safety and Health (FReSH) Community of Practice. 2013. http://www.extension.org/pages/63151/entrapment-risk-due-to-flowing-grain#.UuGfMhBMH0O
Grain bin danger – just 20 seconds to entrapment. Delta Farm Press. 2013. http://deltafarmpress.com/corn/grain-bin-danger-just-20-seconds-entrapment
Suffocation Hazards in Grain Bins. University of Arkansas Division of Agriculture, Publication FSA1010. http://www.uaex.edu/Other_Areas/publications/PDF/FSA-1010.pdf
Grain Engulfment in Agricultural Operations. University of Minnesota Injury Prevention Project, PubH 6120. 2011. http://blog.lib.umn.edu/ublk201/agsafety/
Management of Stored Grain with Aeration. University of Minnesota Extension Publication WW-01327. 1991. http://www.extension.umn.edu/distribution/cropsystems/dc1327.html
Buried Alive: Grain Suffocation Hazards. A publication of the Loss Control Education Unit and Public Relations Department of North Dakota Workers Compensation. 2002. http://acsdia.org/Docs/grainSuffHazard%5B2%5D.pdf
Grain Bin Safety Resources. Oklahoma State University Extension Stored Products Research and Education Center (SPREC). http://storedproducts.okstate.edu/Safety.html
Grain Bin Entrapment: What if it Happens to You? A case study from an Oklahoma county elevator. Oklahoma State University Cooperative Extension Service, Publication CR-1726. http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-2207/CR-1726web.pdf
Hazards of Flowing Grain. Penn State Extension, Publication E 43. 2013. http://pubs.cas.psu.edu/freepubs/pdfs/e43.pdf
Frequently asked questions about flowing grain entrapment, grain rescue and strategies, and grain entrapment prevention measures. Purdue University Cooperative Extension Service. 2011. http://extension.entm.purdue.edu/grainlab/content/pdf/QuestionFlowingGrainEntrap.pdf http://extension.entm.purdue.edu/grainlab/content/pdf/2012GrainEntrapments.pdf
Annual Summaries of Grain Entrapment in the United States. Purdue University. 2012. http://extension.entm.purdue.edu/grainlab/index.php?page=pubs/safety.php
Safety During Grain Handling, Drying and Storage. Extension publications from Purdue University Post Harvest Grain Quality & Stored Product Protection Program. http://extension.entm.purdue.edu/grainlab/index.php?page=pubs/safety.php
NIOSH FACE Program. To search for fatality case investigations involving grain engulfment, use the “search” box and type in key words. http://www.cdc.gov/niosh/face/ Fatality investigations involving grain vacuums include: 12IA001, 09IA012, 98IA035, 93MN007.
Prevent fatalities from grain entrapment. Iowa FACE Program Hazard Alert 10-2011. http://www.public-health.uiowa.edu/face/alerts/1011Alert.pdf
Promoting and Protecting the Safety and Health of Farm Workers and Their Families This publication was supported by Cooperative Agreement Number U54 OH007548 from CDC-NIOSH through an award to the Great Plains Center for Agricultural Health. Its contents are solely the responsibility of the authors and do not necessarily represent the views of the CDCNIOSH.
Great Plans Center for Agricultural Health
Promoting and Protecting the Safety and Health of Farm Workers and Their Families
The University of Iowa College of Public Health, Iowa
City, Iowa www.public-health.uiowa.edu/gpcah/
Gr.EE Revised 1/2014
Publication #: Gr.EE Revised 1/2014
Disclaimer and Reproduction Information: Information in NASD does not represent NIOSH policy. Information included in NASD appears by permission of the author and/or copyright holder. More