Frequently Asked Questions
The following questions and brief answers relate to the causes of, prevention, and response to entrapments, engulfments, entanglements, asphyxiations, falls, and electrocutions in agricultural confined spaces, including at grain/feed storage, handling, and processing facilities. The core content is used with permission from the Liberty Grain Rescue System© User’s Manual, Edition 10, 2018. The responses are not meant to be comprehensive but rather an overview of the topic.
Agricultural Confined Spaces
An agricultural confined space is any space found in an agricultural workplace that was not designed or intended as a regular workstation, has limited or restricted means of entry or exit, and has associated with it potential physical and/or toxic hazards to workers who intentionally or unintentionally enter the space.
• A space large enough and so configured that a person can bodily enter and perform assigned work; and
• A space that has limited or restricted means for entry and exit (for example, tanks, vessels, silos, storage bins, hoppers, vaults, or pits); and
• A space not designed for continuous human occupancy.
- A space large enough and so configured that a person can bodily enter and perform assigned work; and
- A space that has limited or restricted means for entry and exit (for example, tanks, vessels, silos, storage bins, hoppers, vaults, or pits); and
- A space not designed for continuous human occupancy.
Plus one or more of the following:
- Contains or has the potential to contain a hazardous material (atmosphere)
- Contains a material that has the potential for engulfing an entrant
- Has an internal configuration such that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor which slopes downward and tapers to a smaller cross-section
- Contains any other recognized serious safety or health hazard
- 29 CFR Part 1910.146 Permit-required Confined Space Standard
- 29 CFR Part 1910.272 Grain Handling Facilities Standard
Both of these standards are included as attachments. Currently, the 1910.272 standard takes precedence over OSHA 1910.146. Both standards, however, are not enforceable on most production agricultural operations.
Under the current OSHA definitions, most agricultural workplaces with confined spaces are exempt from both of the most relevant confined space standards. The exempted sites include: farms, feedlots, and seed processing operations. In other words, fire/rescue personnel responding to an entrapment in a grain bin or manure pit on a farm could interpret these facilities as not being covered by the OSHA confined space standards, even though the structures are technically confined spaces. The same incident at a commercial grain elevator would fall under the current OSHA standards. It is a good standard operating procedure to treat all confined spaces as hazardous regardless of whether or not the facility is exempt from OSHA standards.
The Hazardous Occupations Orders for Agriculture (HOOAs) for agricultural workpaces, a part of the Fair Labor Standards Act (FLSA), specifically prohibits the employment of youth under age 16 to work in specific types of confined spaces within agriculture. The prohibitions identified are specifically “working inside: (a) a fruit, forage, or grain storage designed to retain an oxygen deficient or toxic atmosphere; (b) an upright silo within two weeks after silage has been added or when a top unloading device is in operating position; (c) a manure pit; or (d) a horizontal silo while operating a tractor for packing purposes. Once a youth reaches the age of 16, there are no specific restrictions for employment in exempt agricultural workplaces, including performing activities within confined spaces. In most settings, however, the allowable age for a young worker to enter a confined spaces is 18, and only if properly trained and supervised.
“If you have to use your hands to get into a space, it’s a confined space.”
This simple definition may not apply in every circumstance, but it provides a means to have workers and fire/rescue personnel to stop and think before entering a potentially hazardous situation. This definition is also easy for young workers to remember.
The following are examples of confined spaces that are commonly found in agricultural workplaces and involved previously in the need for emergency first responders to rescue entrapped individuals.
- Grain and Feed Storage Facilities
- Corrugated steel bins (all sizes)
- Steel tanks or silos
- Concrete silos
- Flat grain storage buildings
- Wooden feed storage structures
- Sumps and tunnels under storage facilities
- Dump pits
- Open grain piles
- Forage Storage Structures
- Concrete stave and poured silos, including those designed to be oxygen limiting
- Wooden silos
- Steel/ceramic glass lined oxygen limiting silos (e.g. Harvestore®)
- Horizontal or bunk silos
- Manure Storage Structures
- Below floor storage pits and tanks
- Sump/pump pits
- Above ground manure storage tanks (e.g. Slurrystore®)
- Ponds, lagoons, and open pits, especially those with steep banks
- Agricultural Transport Vehicles
- Grain transport vehicles (trucks, gravity bed wagons, auger carts)
- Manure transport vehicles (tanks and applicators)
- Food grade bulk transport vehicles (milk, juice, corn syrup)
- Sprayer and chemical transport vehicles
- Agricultural Equipment
- Combine separation area
- Bale chamber on hay packaging equipment
- Forage and silage dump wagons
- Feed grinders/mixers
- Feed mixer wagons
- Cotton module builders
- Grinder/mixer machines and tub grinders
- Environmentally-controlled fruit and vegetable storage units
- Bulk liquid storage tanks (milk and juice)
- Food Processing and Storage Equipment/Facilities
- Storage and mixing tanks, bins, and silos
- Fermentation vessels (pickling and wine vats)
- Environmentally controlled fruit and vegetable storage units
- Bulk liquid storage tanks (milk and juice)
- Containment areas around diked storage tanks
- Trenches and other on-farm construction/excavation sites 4 feet deep or more
- Wells, cisterns, dry wells, septic tanks
- Grain driers
- Fuel storage tanks
- Greenhouses (during certain operations such as fumigation)
- Containment ponds
Based upon an assessment of nearly 3,000 document incidents involving injuries or fatalities in agricultural confined spaces, the following potential hazards were identified.
- Entrapment and engulfment in loose or free flowing agricultural materials (e.g. grain, silage, feed, seed, fertilizer) within storage structures or transport vehicles resulting in suffocation or injury. This type of incident accounts for the single largest share of all documented incidents.
- Suffocation/asphyxiation within a confined space due to exposure to toxic gases or insufficient levels (<19.9%) of oxygen. The largest percentage of these incidents are related to manure storage and handling.
- Drowning in liquids present within the confined space, including manure pits and lagoons.
- Injuries associated with entanglement in energized components within the confined space. The primary agents are in-floor augers, sweep augers, and stirring augers.
- Acute respiratory distress due exposure to toxic dust, molds, and other airborne hazards.
- Falls into confined spaces or from structures containing confined spaces.
- Heat stress/exhaustion due to high temperatures within confined spaces.
- Hypothermia due to extended engulfment/entrapment in chilled grain or environmentally controlled spaces.
- Injuries caused by first responders to victims during extrication efforts from a confined space.
- Injuries to first responders attempting to conduct rescue and recovery operations in and around confined spaces.
- Explosions and fires associated with confined spaces where flammable liquids are stored or flammable dust or gases are present.
- Exposure to excessive noise levels within the space.
- Post-traumatic psychological conditions related to entrapment and extrication.
Yes, cases have been documented in which the victim used the known hazards found in agricultural confined spaces to take their own life. Examples include oxygen-limited silos that contain an environment that cannot support life.
Agricultural Waste Rescue Strategies
Agricultural Waste Storage and Handling Facilities
Yes. One of the by-products of decomposing agricultural waste is the gas methane. If properly managed this gas can be used to operate internal combustion engines to generate electrical power. If allowed to accumulate, however, and ignited, methane can explode and cause fires. One reason agricultural waste storage areas are ventilated is to reduce the risk of methane from accumulating to explosive levels.
Yes. Manure bio-digesters includes fully enclosed confined spaces with limited access or egress and can represent a risk for workers who work close by. The risks associated with manure bio-digester systems include: fire and explosions, asphyxiation, biohazards, and toxic gases exposure.
No. The first action a first responder should take is to call 911 to request emergency assistance. Only emergency responders who have been trained to perform rescues from a confined space and who are appropriately equipped with all proper PPE, including SCBA, should attempt to rescue the initial victim.
In 2012, a 48-year-old farmer and his two sons, 18 and 14, died in a 200-million-gallon pit filled with manure due exposure to toxic gases. Emergency first responders used several vacuum trucks to pump the slurry from the pit and recovered the bodies of the three victims.
A leading cause of death associated with livestock waste storage facilities is attempts by first responders to assist or rescue a victim entrapped or overcome inside a hazardous confined space. In two cases on dairy farms, a total of 10 people died, with 8 of them attempting to rescue the initial two victims.
The data shows that the majority of emergency responses to these facilities end up being body recoveries. It is extremely important for fire/rescue agencies serving areas with large livestock operation with large capacity waste storage, that they develop Standard Operating Procedures for responding to these facilities to prevent unsafe rescue attempts.
In some cases, the only solution is to drain or pump out the storage space to recover the victim. There are in most areas local contractors who specialize in handling and transporting large quantities of waste, who could be utilized.
No, if you believe you are untrained or improperly equipped to complete a task or the task is too dangerous to perform, you have a right under the provisions of OSHA to refuse to perform the task without threats to your employment status.
Asphyxia occurs due to an inadequate level of oxygen in the atmosphere due to displacement of oxygen by other toxic gases such as hydrogen sulfide, ammonia, and methane. Suffocation causes death by reduction of the oxygen concentration in the individual breathing zone, or by being confined in small airtight space (suffocation in manure pit).
Yes and No. Livestock waste are usually stored and often transported in spaces or containers recognized as confined spaces. An agricultural confined space is defined as any space found in an agricultural workplace that was not designated or intended as a regular workstation, has limited or restricted means of entry or exit, associated with potential physical and/or toxic hazards to workers who intentionally or unintentionally enter the space. This includes; a manure storage structure, below-floor storage pit, a sump pit, ponds, lagoons and open pits, manure digester and manure handling vehicles such as tankers, applicators, and spreaders. From a regulatory perspective, current OSHA regulations exempt these spaces found on farms, regardless of whether or not the spaces meet the technical definition of a confined space.
Regardless of the definition used to designate confined spaces by OSHA, all manure or agricultural waste storage structures should be treated as hazardous confined spaces.
When livestock waste, especially manure, decomposes, it generates gases that either replace the available oxygen in a space, and/or are toxic to humans and livestock. These include:
- Carbon dioxide (CO2) – replaces the oxygen in the atmosphere
- Methane (CH4) – potentially explosive gas generated as manure decomposes
- Ammonia (NH3) – harmful to lungs and eyes
- Hydrogen sulfide (H2SO4) – most toxic of the gases generated as manure decomposes – has a rotten egg odor
No. Entering any confined space containing livestock waste is an incredibly dangerous activity with a high probability of resulting in a fatality due to the presence of toxic gases or lack of oxygen. It is hard to imagine a good reason for an agricultural worker to enter a tank or structure containing liquid manure. Even entering a confined space holding transfer pumps or valves is extremely dangerous because of the potential for toxic gases to settle into low lying areas of buildings and should only be performed by trained personnel with the ability to accurately test the air quality and with access to the appropriate personal protective equipment. This activity is considered so dangerous, that under the provisions of OSHA, employees can refuse to comply with directives by their employers to enter the spaces.
No. An N-95 mask is designed to protect the wearer from particulates, not the toxic gases and vapors produced by livestock waste. It should also be anticipated that the level of oxygen in a confined space containing agricultural waste is not adequate to support life.
An N-95 respirator does not provide protection from the environment inside an agricultural waste storage structure.
The general types of current livestock waste storage facilities include:
- open piles of dry waste (sometimes composted)
- underground liquid manure storage structures built under livestock housing areas
- lagoons or open liquid storage ponds (in some cases these maybe covered)
- above ground, silo-type liquid storage tanks
- covered composting structures
- anaerobic biodigester holding tanks and structures
All living organisms produce waste, including humans and livestock. For most Americans, waste disposal has become a hidden or nearly invisible process utilizing toilets, pipes, septic tanks, and waste treatment plants. In agriculture, the sheer volume of livestock waste that must be stored, handled, or transported makes the process much more visible, and sometimes disagreeable when others in the community are exposed to its odors or environmental threats due to spills. Each year it is estimated that U.S. farmers and ranchers must dispose of over one billion tons of livestock waste as a by-product of producing meat, eggs, and other livestock related products. This would fill 66 million large dump trucks, each carrying 15 tons (30,000 pounds) of manure in a line that would stretch over 252,000 miles. More than 300,000 farms apply manure to 24 million acres of croplands. Rich organic material in livestock waste is used to improve soil quality and to increase crop productivity. Agricultural waste, when handled properly, is part of the cycle of life.
Asphyxiation or suffocation related incidents were the most frequently documented fatality cases associated with all livestock waste-related cases. These cases, along with entanglement in manure handling machinery, represented about 60% of all cases. The terms “asphyxiation” and “suffocation” appeared to be used interchangeably in some reports, even though they are defined differently in the medical literature.
The primary activity at the time of injury was repair or maintenance activities in livestock waste storage and handling facilities, which included repairing, maintaining, or servicing of facilities and equipment. Working on malfunctioning or plugged pumps was identified in several cases The second most frequent activity was related to rescue attempts or being a secondary victim including first responders. It is estimated that historically approximately one out of five incidents involved a person, or persons, attempting to rescue an initial victim.
Most livestock waste injury incidents have occurred in July and October. July is believed to reflect warmer weather that contributes to higher levels of toxic gases produced in livestock waste storage structures and the more intensive application of liquid manure following wheat harvest in the June-July period in the states identified as having a larger number of cases. October is more likely the result of manure application following corn and soybean harvest prior to the winter months when manure application is more difficult or in some cases restricted by environmental rules.
Dairy farm operations were identified as the most frequent type of farm involved in previous livestock waste incidents, with an unexpectedly high fatality rate (68%), representing 30% of all cases, while 16% occurred on swine farms.
The Hazardous Occupation Orders for Agriculture (HOOA), a Part of the Fair Labor Standards Act, specifically prohibits the employment of youth under age 16 to work in specific types of agricultural confined spaces. The prohibited worksites include but are not limited to: (a) a fruit, forage or grain storage designed to retain an oxygen deficient or toxic atmosphere; (b) an upright silo, within 2 weeks after silage has been added or when a top unloading device is in operating position; (c) a manure pit; or (d) a horizontal silo while operating a tractor for packing purposes. Once a youth reaches the age of 16 there are no specific restrictions for employment in exempt agricultural workplaces, including inside a confined space. However, recent civil litigation has clearly shown that the courts and juries do not think favorably towards employers who assign young and beginning workers tow enter any form of confined space.
The primary ingredient of agricultural waste is livestock manure, including both solid waste and urine. In addition, agricultural waste can include water used for cleaning, residual feed, sawdust, straw, hay, silage, and grain, sand or soil, rainwater or snow runoff and pharmaceuticals used to treat livestock. Most agricultural waste produced in the U.S. is applied to croplands as a soil nutrient.
Some larger farm operations now accept large quantities of food waste to be processed along with other agricultural wastes to generate biogas as a fuel for generating electricity.
Grain Entrapment and Engulfment
One. Older grain bin ladders were designed to have a working capacity of less than 250 pounds. These ladders account for most bin ladders currently found on U.S. farms. The new grain bin safety standards calls for ladders to have a working capacity of 350 pounds. Considering that the average adult male weighs 180 pounds, there should never be two workers standing on a bin ladder at the same time.
Grain entrapments and engulfments account for only a small percentage of on-farm fatalities and injuries. For example, the PUASHP reported that from 2000 to 2020 tractor-related incidents accounted for approximately half of all fatalities, while grain engulfments and entrapments accounted for less than 5%. The Ohio Commission on the Prevention of Injury reported that from 1993 to 2002, there were 250 documented fatalities in Ohio. Tractors incidents accounted for 147 fatalities (58.8%), while grain bins and grain wagons accounted for ten fatalities (4%). The number of non-fatal grain-related incidents is likely 20%-30% higher, since many incidents go unreported when self-extrication is possible, but the number is still a small fraction of the total number of agricultural incidents. And while the overall trend of on-farm fatalities is decreasing, the number of grain related fatalities have remained relatively constant. Currently, it is estimated that less than 5% of all farm-related fatalities involve suffocation, asphyxiation, or entanglement in agricultural confined spaces.
Generally, no. The overwhelming majority of on-farm grain storage structures were designed and fabricated before implementation of the general OSHA workplace safety standards or without consideration of the most relevant OSHA standards (1910.272 and 1919.146). In most situations, the cost of meeting the current standards that apply to commercial (non-exempt) facilities would be significant or prohibitive under the current grain marketing system that farmers are required to use. Many older structures would have to be removed from service due to the lack of adequate anchor points, no lock out – tag out provisions, and lack of fall prevention features on ladders. The most significant barriers would be the need for confined space entry training, acquisition of required personal protective equipment, access to air monitoring equipment and additional trained personnel to provide external support during access to the structures. It would take a major redesign of the grain marketing system to generate sufficient revenue to update current grain facilities on farms to meet the current OSHA Standards. In some cases, the most economical approach to dealing with older, non-compliant grain bins is to salvage them. It is believed that as new, safer grain storage structures are built, older, more hazardous facilities will be retired from use.
Some employers have put in place an operating practice referred to as “O-Entry”. This safety policy prohibits employees from entering a grain storage structure at any time. This policy, however, is almost impossible to fully implement because of current design features. In some cases, these employers contract with “non-employees” to enter the bins, which allows them to claim “O-Entry” for their employees, while still completing tasks, such as bin cleaning, that requires bin entry.
There are several factors that are contributing to the continued documentation of these cases, including:
- Better incident reporting by the media and governmental agencies.
- Increased crop yields due to new production practices and technology results in larger volumes of grain harvested, handled and stored.
- Larger capacity storage facilities on both farms and commercial facilities.
- Larger capacity handling systems.
- Increased cost of energy to dry grain that causes some grain producers to store inadequately dried grain (over 15% for long durations).
- Climate conditions that have increased the amount of out-of-condition grain in storage.
- Aging storage facilities that fail to adequately protect the stored grain from the elements leading to spoilage and difficulty removing the grain from storage.
- New generation of employees who may not recognize the threats associated with grain storage and handling.
Generally, no. Grain storage structures on farms, feedlots, and certain seed processing operation, are currently exempt from most OSHA safety rules including OSHA 1910.272, the Grain Handling Standard. This exemption also covers feed storage structures. However, if the farmer operates a commercial grain storage facility in which he buys and sells grain or stores grain for a fee, his employees could be covered by the OSHA standards. In some cases, farmers with 11 or more employees or who provide migrant worker housing should comply with OSHA workplace safety rules. Enforcement of the OSHA rules can also vary considerably from state to state. Owners/operators of larger farms with 11 or more employees should contact their State Department of Labor concerning their compliance needs. See Attachments for additional information on the OSHA agricultural exemption language.
The two most relevant OSHA Standards that apply to grain storage are, the Grain Handling Standard (OSHA 1910.272) and the Confined Space Standard (OSHA 1910.146). Both are included as Attachments. Currently, the OSHA 1910.272 standard takes precedence over OSHA 1910.146, the Confined Space Standard.
No. Under the Hazardous Occupations Order in Agriculture (HOOA), that is within of the Fair Labor Standards Act, children under the age of 16 are prohibited from being assigned to work inside any confined space, including grain bins, silos, and manure pits. (see www.agsafetyforyouth.info) The children of farmers are, however, exempt from these restrictions. Under the provisions of the Fair Labor Standards Act provisions, a worker must be at least 18 to perform certain hazardous tasks including confined space entry. See Attachments for the applicable provisions of the Fair Labor Standards Act, including language on youth working in confined spaces.
Even though an exempt farmer may not need to comply with federal child labor regulations, placing a child or youth inside a grain storage facility may be considered a form of child endangerment, even for a child raised on a farm.
This once widely used practice consisted of putting one or more workers inside of a grain storage structure while the unloading system is energized to clean crusted grain off the inside walls and to break up crusted grain to prevent plugging. This practice is illegal under the OSHA Grain Handling Standard, (1910.272). No one should be allowed to be inside a grain storage structure while grain is flowing towards the unload openings.
Yes and No. Technically, grain storage bins meet the criteria for being classified as a confined space. However, under the current OSHA Standards, grain storage structures on farms, cattle feed lots and seed processing facilities are exempt from complying with the confined space standards. If located at a commercial facility or industrial setting, the same structure would be classified as a confined spaces and subject to regulation. Some courts have ruled that the intent of Congress when including the agricultural exemption was to exclude on-farm grain storage from the definition of a confined space. However, grain storage structures include all the hazards found in industrial confined spaces and should be respected. Remember, OSHA workplace safety and health standards are minimum expectations for employers and often do not reflect current best work place practices.
Just seconds. With today’s high volume grain handling equipment, a column of free flowing grain can completely bury a victim in less than a minute. A victim has little time to respond before escape becomes impossible. An auger removing grain at 1,800 bushels per hour is handling 150 bushels every 10 seconds. Then imagine the speed of entrapment at 10,000, 30,000, or even 60,000 bushels per hour. If you consider that the human body only takes up 2-3 bushels, engulfment only takes a few seconds. Humans are simply unable to respond fast enough to prevent entrapment.
Most victims of full engulfment in grain die of asphyxiation due to ingestion of grain in the mouth, throat, and nose. Non-fatal injuries that have been documented include exposure to toxic dusts; hypothermia from long term exposure to chilled, wet grain; entanglements in unloading augers; impact injuries from being struck by falling chunks of grain or falls into the storage structure; and limb dislocations due to attempts by rescuers to pull victims from grain. Another concern identified is from the effects of pressure on the body from surrounding grain that can lead to unsafe blood pressure levels and difficulty breathing.
Yes. There have been numerous cases of both entrapments and engulfments in gravity flow grain wagons, semi and straight grain trucks, and railroad cars. The overwhelming majority of these cases historically have been young boys. The average age of victims is between 10 and 15. The percentage of incidents that result in fatalities is higher than other grain-related cases. The flow of grain from these vehicles is designed to be very fast. Semi-trailers can unload 800-1,000 bushels in just a few minutes which makes the risk of entrapment for anyone on top of the load very high. In some cases, the victim will become wedged into the opening making extrication difficult.
With the increased use of grain vacuum machines to handle grain, there have been cases documented in which the victim, using a hand held vacuum inlet pipe, was pulled into the grain and suffocated. This type of entrapment occurred when the inlet tube was placed near the victim’s feet while standing on the surface of the grain. The grain was sucked or removed from underneath the victim. Within a few seconds, the victim was pulled in beyond the point of escape. The vacuum unit is so powerful, removing 1,200 bushels per hour or more, that it is challenging to choke or slow the flow, and some older inlet tube assemblies were not equipped with a means to shut off the flow at the operator station. During rescue attempts in which a grain vacuum machine is used, only those trained in its use should be allowed to operate it. Partial entrapments of first responders have been documented while using these machines. The operator of the inlet tube should always have the ability to shut off the inlet. Grain vacuum machines should never be operated alone. It is strongly recommended that the operator is always standing on a solid surface when vacuuming grain, not on the grain surface.
A comparison was made between agricultural confined space incidents and mining incidents. Historically, there have been more documented fatal incidents in U.S. mines per year than those occurring in agricultural confined spaces. However, that trend changed in 2018 when the number of agricultural confined spaces-related fatalities equaled the number of mining-related fatalities, at 27. Since then, the number of identified fatalities in agricultural confined spaces and the mining industry have been similar.
Yes and No. If used properly and attached to an adequate anchor point, a life line and harness, used in conjunction with an outside observer, provide important measures of safety. However, a life line and harness used without the other required prevention measures provide little protection. There have been numerous reported incidents where the victim entered an unsafe situation alone, tied himself off with life line and harness, yet still became entrapped or suffocated. The only value of the life line, in that case, was that it identified the location of the victim beneath the grain surface. Life lines always require a second observer with the physical ability to maintain tension on the line while the user is inside the space. Even with a life line and harness no one should enter a bin from which grain is being removed from the bottom, or where there is crusted material stuck to the walls of the bin or there is free standing grain. It is interesting to note that several victims were documented wearing only a body harness, with no life line.
No. Almost all U.S. on-farm bins were designed to store grain, not provide adequate anchors to meet the current confined space entry regulations. Roof components or bin ladders are not intended to provide sufficient anchor points and could fail if overloaded. There are efforts underway to develop equipment to retro fit current grain storage structures to provide adequate anchor points, but this equipment is still not widely available and the cost of retrofitting older bins is a significant barrier for many farmers. In some cases, trained first responders can rig adequate anchor points that are on the ground, outside the structure or overhead using an aerial fire/rescue truck. There have been documented cases in which the victim tied himself off to an internal or external bin ladder. The forces, however, of the grain flow were so great that the ladder mounting bolts failed and pulled the ladder into the grain along with the victim. Most bin ladders are designed with a load capacity of less than 350 pounds. Currently, new corrugated grain bins are designed to include an anchor point with a 2,500 pound capacity for accessing bins, but these anchors do not meet fall prevention standards.
Most often, no. Grain that is properly dried and stored does not produce toxic gases. The exception would be where grain has been stored too wet, above 14% moisture content, and carbon dioxide is released as the grain ferments and spoils. This is less likely during cold weather due to the much slower decomposition process being much slower. Wet grain storage bins used to increase the capacity of grain drying systems can also have carbon dioxide present if the grain is allowed to stay in the bin too long. The OSHA standards require, if there is any doubt about the air quality in any confined space, that the air should be tested prior to entry without a self-contained breathing apparatus. Under the OSHA Grain Handling Standard, atmospheric testing is not mandatory for bin entry.
Another toxic air quality issue relates to overheating of grain due to spontaneous combustion caused by grain spoilage. This process can occur in the center of the grain mass and not be visible, but releases both carbon dioxide and carbon monoxide. Entering a smoldering bin of grain can be deadly.
If possible, it is always a good idea to ventilate a storage structure before entering it by opening the top hatches or turning on the aeration fan. Most fire/rescue teams now have access to air quality monitoring equipment which should be used to test for toxic environment if there is any evidence of toxic gases. Very few grain farmers have appropriate equipment to monitor air quality in a confined space.
Due to the possible presence of airborne toxic mold and dust, appropriate respiratory protection should be worn inside grain storage structures. This includes dust masks or respirators such as a NIOSH approved N-95 mask, which removes most airborne particles. These masks become contaminated quickly under heavy dust conditions and should be replaced frequently. Because some respirators such as N-95 masks restrict oxygen flow, they should not be worn by those with certain pre-existing medical conditions. In some workplaces, employers are required to provide fit testing and medical exams prior to being assigned to wear a respirator.
If there is any question regarding the presence of toxic gases, efforts should be made to ventilate the space and full Self-Contained-Breathing-Apparatus should be worn.
Yes and No. Grain dust is not considered toxic to most people but can cause respiratory distress, especially if the dust contains mold spores or other biological agents. Some molds, however, found in grain are considered toxic to both humans and animals. If there are high levels of dust in suspension, respiratory protection is strongly recommended. Some people may be hypersensitive to grain dust and have an allergic reaction that includes flu-like symptoms. An OSHA Fact Sheet on grain dust and a resource on health effects of grain dust is included as an attachment. If there is moldy grain present, there is a high probability that there will be suspended mold spores in the air. Special precautions are needed.
Many of the documented incidents indicate that the majority of victims were working alone at the time of entrapment or that the observer was so far from the controls that they could not shut off the unloading process quickly enough to prevent complete engulfment. Once caught in the flow of grain it takes only seconds until self-extrication becomes impossible. Grain can easily enter the nose and mouth resulting in asphyxiation. The probability of surviving under the surface of grain is very low.
In a small number of cases the victim’s respirator or dust mask, kept the grain from entering the nose and mouth preventing asphyxiation. However, wearing a respirator should never be seen as an appropriate personal protective device to mitigate the risk of entrapment.
Yes. Cases have been documented in standing piles of stored grain and where storage structures have failed, allowing grain to avalanche out of the structure covering nearby workers. Workers have been buried and suffocated beneath bin access doors, not realizing that there was still caked or free flowing grain in the structure. When the access door was removed, the material flowed out and covered the victim. To provide emergency storage, grain is sometimes stored in external piles. As grain is removed from the base of the pile, an avalanche can occur which can bury anyone nearby. Operators of front end loaders around large piles of gain have become entrapped from avalanching grain.
Prior studies conducted by Purdue University’s Agricultural Safety and Health Program (PUASHP) have identified a gap in the research related to safe grain handling, transport, and storage, as well as rescue strategies. For over 30 years, data have been collected and over 1,700 cases of grain entrapments and engulfments have been documented. The overall objective is to identify the hazards associated with grain handling, transport, and storage, and reduce the associated risks through education efforts for farmers and professional grain handlers. In addition, research has been conducted to increase the likelihood of successful rescues from grain entrapment. Findings have been used to develop strategies for training first responders. The PUASHP staff also uses research findings to provide assistance to the grain industry in formulating engineering standards and to government agencies for regulatory issues.
One outcome of this research was the introduction of the first commercially available grain rescue tube that has been distributed to fire/rescue agencies across the U.S.
Agriculture has historically had one of the highest death rates, with approximately 25-30 fatalities per 100,000 workers (National Safety Council Injury Facts). This is ten times higher than the fatality rate for all other industries. While most industries have experienced a declining trend with respect to their fatality rate, agriculture has remained fairly constant, and has been consistently ranked as one of the top three most hazardous occupations.
No. The number of grain-related entrapments and engulfments on U.S. farms and at commercial grain facilities over the past 20 years has stayed relatively constant with 5-year averages running between 30-32 cases per year. The highest number of documented entrapments and engulfments occurred in 2010 with 51 victims, of whom 50% died. Lower numbers of documented cases over the past decade have not substantially modified the trend of these incidents.
The rate of incidents based upon per-bushel handled, though not accurately calculated, has certainly declined. Considering the increasingly amount of grain annually produced and handled, entrapment incidents are relatively rare events. For example, in Indiana, there have been approximately 2-4 cases documented annually for the past 20 years.
An entrapment occurs when a victim becomes buried in grain beyond the point of self-extrication, while an engulfment is an incident where the victim is completely buried or submerged beneath the surface of the grain. Historically, half of documented grain entrapments resulted in full engulfments, which in turn are almost always fatal. A few victims have survived complete engulfment, but, as noted, this is very rare. Typically, a victim entrapped in grain above their knees cannot self-extricate and will require outside assistance.
Historically, approximately 75% of all documented grain entrapment and engulfment victims have been farmers, farm employees, and farm family members. More recently, there has been a slightly growing percentage of victims who are temporary or seasonal employees of commercial grain storage and handling facilities. Almost all incidents have involved adult males, except for suffocations in grain transport vehicles, such as gravity-flow wagons, which have been predominately male children between the ages of 10 and 15. Historically, about 1 in 5 victims have been 21 years of age and younger.
Lack of experience and training is a significant factor. In addition, younger workers tend to be more mobile and thinner allowing them easier access to certain confined spaces. Many cases have involved older workers, or supervisors, assigning a younger worker to enter a confined space because of their greater mobility.
The answer is not always clear, however, the relationship between out-of-condition corn and the increased probability of entrapment is well established. Even though the total acreage of corn and soybeans harvested annually in the U.S. has been relatively the same, the volume of corn produced is substantially greater. Corn production is 3 to 4 times as many bushels as soybeans. Corn tends to be harvested later in the season, has increased exposure to wet weather, has a lower value than soybeans, and is not managed, by some producers, as closely as soybeans. It appears that due to the value differences and the cost of drying corn to a safe storage moisture content, producers have a greater likelihood of storing corn above the 14-15% optimal moisture content which leads to more spoilage, which then in turn, to more difficulty in removing the grain from storage. Again, there is a direct relationship between out-of-condition, or spoiled grain, and the increased likelihood of entrapment.
There is a direct relationship between out-of-condition, or spoiled grain, and the increased likelihood of grain entrapments. Grain that is stored at less than 15% moisture content (M.C.) is less likely to spoil. Grain over 15% M.C. will begin to decompose or “rot”, and is more likely to become infested with insects. Allowing rain or snow into the storage structure through open hatches can also lead to wet grain and spoilage.
Entrapments and engulfments occur where most of the grain is grown and stored. Therefore, more cases are reported from states such as Indiana, Iowa, Illinois, Minnesota, and Ohio where there are large acreages of corn and soybeans, and substantial on-farm storage capacity. Because of storage issues related to corn, including the high humidity of the region, more cases have been documented involving out-of-condition corn than in any other type of grain. Relatively few cases are seen in the upper Midwest (North and South Dakota and Northern Minnesota) or western states where the humidity is lower and more small grains are grown. However, as corn production has moved further north, more incidents are being documented in northern regions of the Corn Belt.
Farmers and their family members have a greater risk due to a number of factors, including:
- Farmers tend to work alone and have no backup in the event of an entrapment.
- Farmers are generally not required to comply with federal confined space safety regulations, such as the requirement to have an outside observer.
- On-farm grain management practices, such as inadequate drying, may lead to more out-of-condition grain.
- Farmers often handle grain less frequently throughout the year, leading to more mistakes and unsafe practices.
- Farms are also an extension of the family home which increases the risk of children being present and exposed to grain storage and handling facilities.
Indiana has more documented cases due to more aggressive data collection efforts. Purdue University has been documenting grain entrapments and engulfments since the late 1960s. It is almost certain that some states that produce more grain and have greater grain storage capacity, such as Illinois and Iowa, actually have had more incidents that remain undocumented. In other words, Indiana has more reported cases due to more aggressive data collection efforts. Recently, Illinois and Minnesota reported the most number of incidents reflecting their greater grain production and storage capacity. Better surveillance techniques, such as online searches, have helped make recent data collection more comprehensive.
Purdue University began documenting cases of grain entrapment and engulfment cases in the late 1960’s. This data eventually was entered into a computer database. In the 1990s the database expanded to include incidents involving other agricultural confined spaces, including manure storage and handling facilities. Current efforts are underway to expand the database to include all types of agricultural-related confined spaces. Currently, nearly 3,000 cases have been documented including over 1,700 in grain storage and handling facilities and about 500 in livestock waste structures.
Grain Entrapment Prevention Measures
First, the most important measure to prevent grain entrapments is proper grain management. Grain that is stored at the correct moisture content, 14% or less for long term storage, and is protected from the elements remains in good condition and is easier to remove from the storage structure without plugging. It is also worth more when sold. There is a direct correlation between out-of-condition grain and the increased probability of entrapment. Other important prevention strategies include:
- Never entering a storage structure while it is being unloaded
- Never entering a grain storage structure without an outside observer or before letting others know your plans (use of entry permit)
- Utilizing lock out/out procedures to ensure unloading equipment is not unintentionally energized while someone is inside the structure
- Clearly posting warning signage communicating the potential for engulfment at each access point
- Always having a working radio or cell phone when working alone or when performing hazardous tasks around grain storage. In some cases, cell phones will not function inside a metal grain binImplementing a policy that all grain storage structures, open piles of grain, and grain transport vehicles are off limits to children, visitors, and non-essential employees
There are two reasons: political and economic. When the U.S. Congress drafted workplace safety and health standards, language was incorporated to exempt farmers, feedlot owners, and certain other agricultural production sites to reduce opposition to the passage of the legislation. Second, the tremendous cost of bringing the hundreds of thousands of on-farm grain storage structures into compliance with the current requirements of the standard would fundamentally force a change in the way agricultural production is carried out and how the prices of crops are determined. It was not economically possible to make the changes needed for compliance without substantial financial investments that were not currently included in the cost of production. This issue, at the time, continues to be a barrier.
The current strategy for improving the safety of grain storage structures is to replace older structures with new ones as structures reach the end of their useful life. There are, however, hundreds of thousands of older bins still in use that have not benefitted from new, safer design features, or are in poor condition that contributes to the risk of grain spoilage.
The first place to look is the local County Extension Office, which has access to grain management resources from across the country. Manufacturers of grain storage systems are also an important resource, along with neighbors who have documented their ability to successfully store grain. There are also websites such as that provide helpful information.
In most cases no. The speed of entrapment is so fast that it is highly unlikely that a worker in the bin has the instinct or reaction capacity to grab a safety line quickly enough. Second, the use of these devices may lead to greater risk taking behavior on the assumption that if a problem occurs, there is always a safety line to fall back on. Finally, past incidents have documented that the draft or the down pressure on an engulfed victim is so great that the roof or bin ladder on a typical on-farm grain bin would probably fail under the load. In nearly all current on-farm storage bins there is not an adequate anchor point to support the weight of an engulfed victim.
Each year a small number of children, nearly all boys ages 10-15, are suffocated while inside grain transport vehicles of some type. Most of these incidents involve gravity flow grain wagons and carts and straight grain trucks. The children were allowed to ride in these vehicles, either empty or full, and became entrapped and suffocated when covered by grain being loaded or unloaded. Children should be prohibited from riding on loads of grain or being transported in empty grain transport vehicles.
Grain Quality and Its Contribution to Entrapment and Engulfments
Grain is a biological product the same as wood, leaves, and other plant material. By its very nature it is designed to decompose if left exposed to the elements. With sufficient moisture, grain will quickly compost or decay back into the soil from which it originated. If kept dry, or less than 14% moisture content, and free of insect infestation, it can be stored almost indefinitely. As grain spoils, it becomes home to a variety of molds, such as on a loaf of old bread, some of these molds can be toxic.
Yes, keeping grain cold helps reduce insect activity and slow biological deterioration. Fans are used on many bins to lower the temperature of the grain during cold weather. Care is needed when cooling grain to not introduce additional moisture under high humidity conditions. Rewetted grain can spoil quickly.
The most obvious sign that grain has spoiled or gone out-of-condition is that it no longer flows freely though the unload system. Next look for crusted grain that can be on the surface or free standing on the walls or in open piles. If there is access to a carbon dioxide meter, levels over 600 parts per million may suggest spoilage is occurring. If the exhaust from the fans is warm, or smells sour or moldy, there is likely spoilage occurring. Remember, out-of-condition grain usually contains a large amount of moldy material that can be a serious health risk.
One of the most common causes of vertically crusted columns of grain is roof leakage or condensation. Water that enters the bin through a hole in the roof can saturate the grain in a specific region of the grain. The moisture migrates downward causing the grain to spoil or mold in a column under the leak. When the surrounding grain is removed, the free standing column of out-of-condition grain remains. Some of these columns or towers can be 10-25 feet tall and contain hundreds of bushels or tons of grain. They can collapse suddenly, if disturbed, burying anyone inside the structure. These columns of grain should never be broken up from below, but reached through the top opening with a long pole or pipe.
Yes. Some grain types and grain products such as feed or dried distiller grains can become spoiled or compacted if left even for short periods in wagons, trucks, or railroad cars. Cases have been documented in which workers entered these vehicles to breakup compacted grain and were entrapped when the material suddenly began to flow. No one should ever stand on the grain surface of a grain transport vehicle that is being unloaded. Children should never be allowed to ride in or on any grain transport vehicle.
- Use of stirrators to mix the grain
- Temperature monitors to detect grain heating, a sign of spoilage and insect infestation
- Installation of vents on roofs away from the direction of prevailing winds
- Sound roof with overhanging eves that prevent rain and snow from blowing in
- Weather seals on doors, hatches, and other access points
- Keeping top bin hatches secured when not in use
- Maintaining a weatherproof seal around the base of the bin
- Installation of inside ladders
- Warning decals posted at all access points
- Cleaning the structure every time it is emptied to reduce the likelihood of passing along mold and insect contamination to the next crop
Coring the bin is a management practice that involves removing a load or two of grain from the structure once it has been filled to remove dusts, fines, and broken corn that tend to accumulate in the center of the bin during filling. This damaged material tends to attract insects and more readily absorbs moisture, leading to spoilage, crusting, and plugging the flow. By removing this material, the quality of the grain is enhanced, it’s storability increased, and the risk of entrapment is reduced.
Grain that has not been dried properly (to under 15% moisture content) will begin to spoil and form crusting or large clumps of grain glued together by the mold and spoiled material. This crusted material can prevent the grain from flowing freely and causes plugging at outlets. To regain flow through the outlets, workers will enter the grain storage structure and use long pipes to reach the outlet to break up the crusted material. This may expose them to crusted surfaces covering voids or sudden flows of grain that are nearly impossible to escape from. In addition, crusted material can stick to the walls of the storage structure. A worker who attempts to break the crust free from the wall from below can also be buried under a sudden avalanche of grain.
Grain Rescue Strategies
If spoiled, grain can form free standing piles or columns that are left after the loose grain is removed from the structure. If disturbed, these columns can collapse burying anyone near their base. In some cases, these columns can be 15, 25, 40 feet high comprised of tons of grain in larger bins. First responders should never enter a bin with these crusted columns in place. There are cases documented in which crusted grain was a significant barrier to accessing the victim by putting first responders at risk of entrapment.
Crusted grain poses a significant risk to first responders attempting to reach an entrapped victim because of the unpredictable nature of its stability.
There have been cases, especially involving rural volunteer fire/rescue units, in which personnel left the scene and returned home without any decontamination. This has resulted in allergic responses of family members due to the mold spores and grain dust adhering to the responder’s clothing and body. Following an incident at a grain storage facility, most likely to have involved spoiled or moldy grain, first responders need to have protective gear decontaminated and their clothing washed. They should also shower to remove hazardous dust from their skin and hair.
Yes, Because of the electrical power required to operate grain driers, sweep augers, and unloading equipment, nearly all grain bins are supplied with electrical power. There have been numerous cases of farmers who were electrocuted when equipment such as portable augers, metal ladders, and metal probes made contact with exposed overhead powerlines. First responders must identify overhead powerlines immediately before any equipment is put into position. If necessary, the power supplier should be contacted to disconnect the service to the facility.
Due to inappropriate storage or rewetting of grain, large chunks of spoiled grain can become attached to the bin walls. If disturbed, these chunks, which can in some cases weigh thousands of pounds can break free and collapse on anyone below. Entering underneath crusted grain can prove deadly. This activity is also forbidden by OSHA regulations.
No. If grain inside a grain storage structure is heated and smoking there are NO good reasons to enter the structure, even if a victim is present. First, when grain becomes hot enough to smoke, it is releasing toxic fumes and the space cannot support life. Second, if there are hot spots within the grain mass, there is a high probability that there will be voids that a responder can fall into. The risk is simply too great for causing a secondary victim to have anyone attempt a rescue inside a smoking grain bin.
Each year someone, usually a young male, age 10-15 is entrapped in a grain transport vehicle. He was riding on the surface of the grain, and the unload gate was opened causing him to be pulled into the flow of grain toward the opening. In many cases, the victim’s body became wedged into the opening. Unfortunately, most of these cases result in a fatality.
If the victim is partially entrapped, the bottom opening should not be used. Otherwise, the victim will be pulled deeper into the grain, and possibly suffocated.
The side walls, at the victim’s level can be cut releasing the grain. In several cases involving gravity grain transport wagons, the wagon was flipped on its side releasing the grain and the victim onto the ground.
Attempting to physically pull the victim from the grain can result in serious injuries, including dislocated limbs, which have been documented, especially to children.
Entrapments in semi-trucks have occurred. Again, the unload system should not be used, or there is a risk of completely burying the victim. A grain vacuum machine, if available, or cutting open the side wall of the trailer to release the grain are options. In some cases, large semi-truck trailers are double walled. Access will require cutting both walls.
Grain-related entrapments tend to be high profile incidents that are given an unusually large amount of media coverage. These incidents demand a large number of first responders due to the limited access to the victim and the large amount of grain that must be removed to access and extricate him. In reality, these incidents are extremely rare and in the majority of documented cases result in a body recovery rather than a successful rescue. A strong argument could be made that the investment in training and equipment to address this problem, is disproportional to the demands placed on first responders for other types of serious agricultural-related incidents such as tractor overturns and machinery entanglements.
Prior studies conducted by Purdue University’s Agricultural Safety and Health Program (PUASHP) have identified a gap in the research related to safe grain handling, transport, and storage, and rescue strategies. Data has been collected for over 30 years, and over 1,700 cases of grain entrapments and engulfments have been a documented. The overall objective is to identify the hazards associated with grain handling, transport, and storage, and reduce the associated risks through education efforts for farmers and professional grain handlers. In addition, research has been conducted to increase the likelihood of successful rescues from grain entrapment. Findings have been used to develop strategies for training first responders. The PUASHP staff also uses research findings to assist the grain industry in formulating engineering standards and to government agencies for regulatory issues.
One outcome of this research was the introduction of the first commercially available grain rescue tube that has been distributed to fire/rescue agencies across the U.S.
No. Applying the needed force to free a victim deeply buried in grain has a high risk of causing serious bodily injury and even death. The drag and weight of the grain on the victim’s body is so great that it may take hundreds of pounds of pull to free him. These forces have been calculated to exceed four times the victim’s body weight. In some cases, the victim may also have pre-existing conditions such as knee or hip replacements, or chronic back injuries that could be complicated by applying excessive force. The safest extrication strategy has been to remove the grain from around the victim using a grain containment system and then lift him free. A victim wearing a full-body harness and accessible with a lifeline should be secured to an appropriate anchor point. The harness distributes the victim’s body weight reducing the risk of injury. Historically, however, most victims are not wearing a body harness at the time of entrapment. Great care should be taken to limit the amount of time a victim is supported by a body harness when entrapment occurs.
One injury that has been reported due to forceful extrications from grain is spinal separation.
This risk has been documented using spinal columns being removed from grain masses. Forceful extrications should never be used to remove entrapped victims.
First, the amount of grain that needs to be removed to free a victim is substantial and requires large capacity grain handling equipment such as a gain vacuum machine. Second, the nature of grain to free flow makes it nearly impossible to keep it from flowing back onto the victim without some form of barrier such as a coffer dam or rescue tube. Rarely, has a partially entrapped victim been extricated by digging them out regardless of the number of first responders involved.
Historically, it has been found that building a grain retaining wall or coffer dam around the victim and then removing the grain from within the protected space is an effective rescue strategy. In the past, pieces of plywood, back boards, garbage cans and barrels with the bottom removed, and other items have been used successfully to protect the victim from back flowing grain. Currently, there are several commercially available grain rescue tubes that have been demonstrated to be effective extrication tools for partially entrapped victims. A list of contact information for commercially available grain rescue tubes is included as an attachment.
The quickest method that has been found to remove grain from inside the retaining wall or tube is a portable vacuum. If the containment space or rescue tube size is kept to a minimum around the victim, the amount of grain that needs to be removed is relatively small, usually not more than two to four bushels. Small, portable, battery powered vacuums have been successfully used to remove the grain without the need for power cords. Portable shop vacuums, approved for use in commercial grain elevators, have also been demonstrated to work effectively. Small portable, battery powered augers are also available from a few manufacturers.
Grain is conditioned, by passing dry outside air through the grain mass using large fans to prevent spoilage. As the outside temperature drops the cold air drawn into the bin can reduce the grain temperature at the core of the structure to near outside temperatures, which may be in the 30’s and 40’s. A victim deeply buried in cold grain can become chilled quickly, leading to hypothermia. It may become necessary due to extended rescue procedures to provide blankets or other warming aids to prevent hypothermia. Chemical hand warmer packets have been used to help keep victims warm.
In most cases, even if fully submerged, the victim will be located directly below the center of the funnel shaped surface of the grain or directly over the outlet from which grain was being drawn at the time of entrapment. If the grain flow duration is longer than a few minutes it is very unlikely that the victim will be near the surface of the grain. In most cases there is no need to probe for the victim since his or her position can be closely estimated. It is also important not to send in first responders into the structure, especially if the victim is fully engulfed or deeply entrapped. Entering the structure could cause additional grain to avalanche down onto the exposed victim or burying the engulfed victim even deeper. Entering any structure that contains crusted grain could also place first responders at risk of entrapment.
The victim will usually be at the bottom of the indentation formed in the grain surface directly over the outlet in the floor. He will be well below the upper levels of the grain. There can be 10 or more feet of grain above the victim in larger bins. Entering the structure can cause the higher grain along the bin walls to cascade down onto and possibly cover the victim or bury them more deeply in the grain. There are documented cases of first responders causing grain flows that have fully engulfed partially buried victims. Only one or two fully secured first responders should attempt to approach the victim using some form of surface covering, such as tarps, carpets, snow fence, etc. to reduce the likelihood of avalanching additional grain.
If the victim cannot be safely reached, the grain around him will need to be removed by using a grain vacuum machine or cutting open the bin walls, allowing the grain to be released.
A variety of materials have been used to enhance the footing for first responders during a rescue attempt inside a grain storage structure. Without a means of support, the responders sink deeply into the loose grain making movement difficult and exhausting. Snow fence, carpeting, canvas, sheets of plywood cut to fit through access hatches and conveyor belting have been successful used. One item found useful has been two-liter soda crates laid upside down to form a solid path.
No. Fully engulfed victims have been known to survive for a few hours – especially when there were air pockets between spoiled clumps of grain or the victim was able to cover his mouth and nose, or was wearing a respirator. This scenario, however, is rare. In a recent case, a victim survived for several hours under the surface of the grain because he was wearing a full-face air filtration system that kept grain out of his airway. Rescue efforts should continue until the status of the victim can be confirmed. Respirators, however, should not be used to mitigate the consequences of entrapment.
Generally, no. It is not the pressure of the grain on the victim that suffocates the victim, but more likely the grain that obstructs his air way. However, fully and partially buried victims have reported feeling the increased pressure of rescuers walking on the grain surface above them, which is another reason to minimize the number of rescuers on the grain surface. Cases have been reported in which large masses of spoiled or frozen grain have fallen on individuals, causing injury.
The belief that the pressure of the grain can cause suffocation and physical injury may stem from the observations that fatality victims of engulfment may have skin deformation caused by the kernels of grain pressing against the skin following death. Victims that are deeply buried in grain can exhibit elevated blood pressure and difficulty breathing. A common victim complaint is exhaustion due to their effort to self-extricate from the grain. In some cases the victim is so exhausted they need to be carried out of the bin
The typical grain bin has a two part access door system that includes an outside door that opens outward and an inside door that swings in. The outside door can be easily opened by releasing the outer latch. The inside door, however, cannot be opened if there is grain in the bin because of the weight of the grain against the door. Even if the door could be opened or cut, the rapid uneven flow of grain out of the opening could cause the bin to become unstable and collapse or expose first responders to the risk of being buried under the rapid release of grain. On some new bins there is an interlock system that requires the inter door to be in place before the outer door can be secured.
Not always. If someone forgot to close the inside door before filling the bin, the grain will rapidly flow out of the bin and engulf anyone near the door. Fatalities have been documented in such circumstances. If the outside door is bulging out or grain is leaking out around the edges, the area should be secured and efforts made to remove the grain from the structure. No attempt should be made to open the door. It is also possible for a victim to be buried beneath an inspection door on a hopper bottom bin if the door is removed with the grain still inside the bin.
A variety of injuries have been documented to first responders involved with a grain storage rescue including: falls from bin, overexertion, allergic response to suspended mold spores and dust, overheating due to the higher temperatures that can develop inside the bin, and being run over by equipment being used to remove evacuated grain from around the bin. There have been a few documented cases in which first responders have become entrapped in grain during victim recovery efforts or while using a grain vacuum machine. Not all fire/rescue personnel are in the physical condition needed to carry out a rescue inside of a grain storage structure.
No. Turning on the unloading auger or opening the bottom openings will cause the victim to be immediately drawn deeper into the grain mass. There is also the possibility that the victim would make contact with the unload auger. Extrication, in most cases, involves removing the grain from around the victim. Those first responders who arrive at the scene first should lock out all controls or shut off power to prevent anyone from intentionally or unintentionally energizing the unloading equipment. In other words, the unload system should never be used to free an entrapped victim.
On small grain storage bins (less than 30,000 bushels), the quickest way to release the grain to reach a completely submerged victim is to cut openings around the base of the bin and allow the grain to flow directly onto the ground. The recommended strategy is to cut “V”-shaped openings as high up on the side of the bin wall as possible or at the level that the victim has been located. This action will result in less grain having to be removed. Openings should be cut uniformly around the base of the bin to allow for even or uniform grain release and reduce unequal pressures on the structure. The cutting method depends on the type of cutting equipment available to first responders. Air powered chisels, abrasive wheels, cutting torches and reciprocating saws have been used to cut open metal bins. Each has its advantages and disadvantages. Each requires special training to use.
On larger bins the bottom panels may be assembled in layers to strengthen the bin walls which will make cutting extremely difficult. The use of top unloading grain vacuum machines would be a safer alternative.
Under no condition should a concrete silo containing grain be breached to remove grain in order to reach a victim. A silo can easily contain 3 million pounds of grain that could become highly unstable if unloaded unevenly.
Unloading grain from a large structure is a complex time-consuming activity. In some cases, it will involve moving 30, 50, or 100 semi-loads of grain. There will be a need for skid steer loaders, or other material handling equipment. Consider contacting a local grain salvage company to advise on the most efficient way to remove grain, especially if it is out-of-condition.
Yes and No. It is not recommended that holes be cut into the side of larger grain storage structures such as concrete silos, welded steel tanks, or corrugated steel bins over 30,000 bushels in capacity. The structural integrity of these structures, if cut, is not well understood or documented. Before cutting openings in any large structure, consult with the manufacturer or a Professional Engineer (P.E.) experienced with the design and characteristics of these facilities. Compromise or failure of these structures can put first responders at great risk of injury or death. If cuts are made they should start as high as possible, just below the level of the grain and progress down the bin allowing the grain to be removed evenly until the victim is uncovered. Again, a safer alternative would be unloading the grain from the top using one or more grain vacuum machines. This, however, is a time consuming process, including locating and transporting the grain vacuum machines to the site.
The goal should be to remove only the amount of grain needed to access the victim, not completely empty the structure.
Yes and No. There have been no documented fires or explosions associated with rapid access to a grain storage structure. However, many cutting strategies use heat generating tools, and corn is combustible. A charged line should be available whenever cutting on a steel structure. The preferred cutting tool would be an abrasive wheel saw. Full turn out gear, including eye and hearing protection, should be worn when cutting open a bin.
If high levels are being generated by movement of the grain, cutting activities should cease to reduce the risk of a grain dust explosion.
Most corrugated grain bins are fabricated using galvanized metal panels. Using heat generating tools could generate toxic zinc fumes. Full respiratory protection should be worn. Of course, eye protection should be worn whenever power tools are being operated.
Yes. As undried corn with more than 14-16% moisture content begins to spoil, it releases carbon dioxide that can accumulate above the surface of grain. In some cases, levels of CO2 have been documented above what is considered safe without self-contained breathing apparatuses (SCBA). If there is any doubt regarding the air quality inside the bin, it should be tested prior to entry so that appropriate personal protective equipment can be used. There have been documented asphyxiations in wet grain storage bins due to lack of oxygen.
A common barrier to accessing a grain bin while wearing an SCBA, is the size of a typical bin access door, which is around 24 inches in diameter. It’s almost impossible for a first responder to enter such a small access point wearing a SCBA.
Spoiled grain can also lead to spontaneous combustion or heating of the grain which can release both carbon dioxide CO2 and carbon monoxide (CO). First responders have become overcome by the toxic fumes released from overheating grain.
Turning on the aeration fan during a rescue will provide an air flow to a victim that may be completely buried and contribute to better air quality inside the bin for rescuers. If the outside temperature is high, the inside temperature will be even hotter, in some cases over 100°F. Air movement through the bin will also help reduce the inside temperature, reducing the risk of heat stress for first responders. In some cases where there is a lot of damaged and dirty grain, turning on the aeration fan can increase the amount of suspended dust inside the bin. Respiratory protection should be available for all first responders at the scene, and should be replaced frequently. Also, excessive dust generated by the fans can increase the risk of a grain dust explosion inside any enclosed space.
A common characteristic contributing to entrapments and engulfments is out of condition grain due to spoilage from molds. During a rescue effort billions of mold spores and organic dust particles become airborne and become a significant respiratory threat to anyone at the scene. A good quality dust mask, such as NIOSH rated N-95 respirators, that are frequently changed, or in some cases, a full self-contained breathing apparatus will be needed. Post assessment of all first responders should take place to ensure that there is no evidence or symptoms of an allergic response that for some individuals may be severe. Symptoms may include shortness of breath, watery eyes, and fever. These signs should be taken seriously and medical attention sought. Some individuals may be hyper sensitive to the dust and mold found in grain storage structures. First responders at the scene should be followed up on the next day to determine if any have experienced negative health effects, including fever, chills, and difficulty breathing.
Due to the frequency that dust protection will have to be replaced during rescue operation, someone should be assigned to locate a large number of dust masks.
No more than two first responders should ever be on the grain surface where a victim is entrapped or engulfed, and only if the grain surface is stable with no risk of entrapment from above or below. Additional personnel will only increase the risk of secondary entrapment due to avalanching grain and further compact the grain, making rescue more difficult. There have been documented cases in which over 25 first responders entered the structure to attempt to dig out the victim. This approach rarely works and it places numerous personnel at unnecessary risk of injury. The physical activity of this many first responders will also cause additional inflowing of grain causing the victim to become buried even deeper and increase pressure on his body. It also exposes, unnecessarily, many more first responders to respiratory hazards. First responders who enter a grain storage structure, whether a bin or silo should be trained in confined space entry and be properly equipped and supported.
Grain vacuum machines have become extremely popular throughout the Corn belt to remove grain from storage structures, especially if the grain has become spoiled and does not flow well. These machines can be found at many commercial grain operations or obtained from contractors who specialize in salvaging out-of-condition grain. It is recommended that at least two grain vacuum machines to brought to the scene in the event that one experiences mechanical problems.
Consider developing mutual aid agreements prior to an incident so that first responders will have access to the equipment and expertise needed to remove large quantities of grain. Only trained personnel should be assigned to operate grain vacuum machines.
Silos and Forage Storage