Dust at harvest can create health problems
By Loretta Sorensen, Midwest Producer
Dusty clouds surrounding combines during grain harvest can trigger uncomfortable short-term respiratory symptoms, but dust from facilities where grain is stored or ensiled can pose serious health problems to grain handlers.
Matthew Keifer, M.D., M.P.H., at Marshfield Clinic in Eau Claire, Wis., says avoiding grain dust while combining helps reduce risk of an adverse reaction. However, dust generated in the field isn’t likely to be the cause of serious health issues.
“Dust from the field isn’t laden with the bacteria often found in grain bins where some grain has molded or decayed,” Keifer said. “If you’re breathing in much dust in the field, you could develop a fever, cough and achy symptoms similar to flu. Generally, within three to four days all those symptoms are gone. It can make you pretty uncomfortable when it happens, but there’s no permanent effect from it.”
Reducing the likelihood of reactions to grain dust in the field can be accomplished by making sure the combine is fitted with appropriate and clean filters that are properly installed. Ensuring door latches fit snugly and all rubber gaskets around windows and doors are in good condition also helps. Keeping the cab as clean as possible reduces the amount of dust circulating in the combine operator’s space.
While dust from fields isn’t often a significant hazard, allergic reactions to it, known as Organic Dust Toxic Syndrome, can be debilitating for some people with chronic health issues or asthma. Field dust from soybeans, corn and other crops consists of inorganic soil particles, organic plant pieces, mold spores, insect parts and endotoxins. Small particles breathed deep into the lungs could cause health problems.
“A lot of grain dust is benign,” Keifer said. “Dust contaminated with bacteria poses the greatest risk.”
There are different types of allergic reactions that include anaphylaxis, eczema, and accumulation of inflammatory cells in the lung. Anaphylaxis can be the result of a bee sting or ingestion of food such as peanuts. Eczema is an autoimmune response and accumulation of inflammatory cells in the lung result from the response of antibodies to an antigen inside the body.
When antibodies respond to antigens, such as bacteria, cells that accumulate in deep lung tissue can damage the tissue. If scarring occurs during tissue healing, the result is stiffening of the tissue and reduced lung performance, which can lead to fibrosis and a condition known as Farmer’s Lung.
“The easiest way to avoid that is to wear a respirator that filters out at least 95 percent of the material in the air,” Keifer said. “Some respirators filter as much as 99 percent of dust particles from the air. The most effective respirator type is one that features a helmet with a mask and a pump that fits on your belt. The respirator pumps air through the respirator filters and feeds fresh air into your breathing space. Even though it can cost as much as $900, it’s the nicest type of respirator to wear because it blows cool air on your face while you’re using it.”
There are seven classes of National Institute for Occupational Safety and Health (NIOSH) approved respirators. The minimal level of approved NIOSH air filtration is 95 percent. Details about NIOSH approved air filters and links to manufacturer brands are available at http://www.cdc.gov/niosh/npptl/topics/respirators/disp_part/.
Exposure to grain dust most often occurs:
• in the combine
• while unloading
• during drying and processing
• in bins
• in an area near any of the above situations
• while grinding/mixing grain and other feed products
Symptoms of grain dust reactions include:
• chest tightness and/or wheezing
• slightly sore/irritated throat
• nasal and eye irritation
• a feeling of being stuffed up and congested all the time
• both chronic and acute bronchitis
Steps to reduce excessive dust exposure include:
• using correct and clean air filters in combines
• avoiding direct exposure to dust whenever possible
• properly adjusting the combine to minimize grain damage and reduce the amount of dust generated
• wearing a certified dust mask that fits properly
• avoiding dust exposure if you have chronic respiratory health issues
• consulting a physician if you feel sick following any dust exposure
• smoking tends to worsen symptoms and reactions to dust exposure
Additional information about preventing and responding to grain dust exposure is available at http://fyi.uwex.edu/agsafety/, key word: grain dust.
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Grain Handling
OSHA has developed this webpage to provide workers, employers, and
safety and health professionals useful, up-to-date safety and health
information on grain handling facilities.
Suffocation is a leading cause of death in grain storage bins. In 2010, 51 workers were engulfed by grain stored in bins, and 26 died-the highest number on record, according to a report issued by Purdue University (PDF) Suffocation can occur when a worker becomes buried (engulfed) by grain as they walk on moving grain or attempt to clear grain built up on the inside of a bin. Moving grain acts like "quicksand" and can bury a worker in seconds. "Bridged" grain and vertical piles of stored grain can also collapse unexpectedly if a worker stands on or near it. The behavior and weight of the grain make it extremely difficult for a worker to get out of it without assistance. OSHA has sent notification letters to approximately 13,000 grain elevator operators warning the employers to not allow workers to enter grain storage facilities without proper equipment, precautions (such as turning off and locking/tagging out all equipment used so that the grain is no being emptied or moving into the bin) and training.
Grain dust explosions are often severe, involving loss of life and substantial property damage. Over the last 35 years, there have been over 500 explosions in grain handling facilities across the United States, which have killed more than 180 people and injured more than 675. Grain dust is the main source of fuel for explosions in grain handling. Grain dust is highly combustible and can burn or explode if enough becomes airborne or accumulates on a surface and finds an ignition source (such as hot bearing, overheated motor, misaligned conveyor belt, welding, cutting, and brazing). OSHA standards require that both grain dust and ignition sources must be controlled in grain elevators to prevent these often deadly explosions.
Falls from height can occur from many walking/working surfaces throughout a grain handling facility. Examples of such surfaces include (but are not limited to) floors, machinery, structures, roofs, skylights, unguarded holes, wall and floor openings, ladders, unguarded catwalks, platforms and manlifts. Falls can also occur as workers move from the vertical exterior ladders on grain bins to the bin roof or through a bin entrance.
Mechanical equipment within grain storage structures, such as augers and conveyors, present serious entanglement and amputation hazards. Workers can easily get their limbs caught in improperly guarded moving parts of such mechanical equipment.
Storage structures can also develop hazardous atmospheres due to gases given off from spoiling grain or fumigation. Workers may be exposed to unhealthy levels of airborne contaminants, including molds, chemical fumigants (toxic chemicals), and gases associated with decaying and fermenting silage. Fumigants are commonly used for insect control on stored grain and many have inadequate warning properties. Exposure to fumigants may cause permanent central nervous system damage, heart and vascular disease, and lung edema as well as cancer. These gases may result in a worker passing out and falling into the grain, thus becoming engulfed and suffocating or otherwise injuring themselves.
The control of worker's exposure to hazards in grain handling facilities are addressed in the OSHA standard for grain handling facilities (29 CFR 1910.272), as well as in other general industry standards. These standards reduce the risk to workers by requiring that employers follow established, common sense safety practices when working in grain handling facilities.
When workers enter storage bins, employers must (among other things):
What are grain handling facilities?
Grain handling facilities are facilities that may receive, handle, store, process and ship bulk raw agricultural commodities such as (but not limited to) corn, wheat, oats, barley, sunflower seeds, and soybeans. Grain handling facilities include grain elevators, feed mills, flour mills, rice mills, dust pelletizing plants, dry corn mills, facilities with soybean flaking operations, and facilities with dry grinding operations of soycake.What are the hazards in grain handling facilities?
The grain handling industry is a high hazard industry where workers can be exposed to numerous serious and life threatening hazards. These hazards include: fires and explosions from grain dust accumulation, suffocation from engulfment and entrapment in grain bins, falls from heights and crushing injuries and amputations from grain handling equipment.Suffocation is a leading cause of death in grain storage bins. In 2010, 51 workers were engulfed by grain stored in bins, and 26 died-the highest number on record, according to a report issued by Purdue University (PDF) Suffocation can occur when a worker becomes buried (engulfed) by grain as they walk on moving grain or attempt to clear grain built up on the inside of a bin. Moving grain acts like "quicksand" and can bury a worker in seconds. "Bridged" grain and vertical piles of stored grain can also collapse unexpectedly if a worker stands on or near it. The behavior and weight of the grain make it extremely difficult for a worker to get out of it without assistance. OSHA has sent notification letters to approximately 13,000 grain elevator operators warning the employers to not allow workers to enter grain storage facilities without proper equipment, precautions (such as turning off and locking/tagging out all equipment used so that the grain is no being emptied or moving into the bin) and training.
Grain dust explosions are often severe, involving loss of life and substantial property damage. Over the last 35 years, there have been over 500 explosions in grain handling facilities across the United States, which have killed more than 180 people and injured more than 675. Grain dust is the main source of fuel for explosions in grain handling. Grain dust is highly combustible and can burn or explode if enough becomes airborne or accumulates on a surface and finds an ignition source (such as hot bearing, overheated motor, misaligned conveyor belt, welding, cutting, and brazing). OSHA standards require that both grain dust and ignition sources must be controlled in grain elevators to prevent these often deadly explosions.
Falls from height can occur from many walking/working surfaces throughout a grain handling facility. Examples of such surfaces include (but are not limited to) floors, machinery, structures, roofs, skylights, unguarded holes, wall and floor openings, ladders, unguarded catwalks, platforms and manlifts. Falls can also occur as workers move from the vertical exterior ladders on grain bins to the bin roof or through a bin entrance.
Mechanical equipment within grain storage structures, such as augers and conveyors, present serious entanglement and amputation hazards. Workers can easily get their limbs caught in improperly guarded moving parts of such mechanical equipment.
Storage structures can also develop hazardous atmospheres due to gases given off from spoiling grain or fumigation. Workers may be exposed to unhealthy levels of airborne contaminants, including molds, chemical fumigants (toxic chemicals), and gases associated with decaying and fermenting silage. Fumigants are commonly used for insect control on stored grain and many have inadequate warning properties. Exposure to fumigants may cause permanent central nervous system damage, heart and vascular disease, and lung edema as well as cancer. These gases may result in a worker passing out and falling into the grain, thus becoming engulfed and suffocating or otherwise injuring themselves.
What can be done to reduce the hazards in grain handling facilities?
On August 4, 2010 and again on February 1, 2011, OSHA issued warning letters to the grain handling industry following a series of incidents including the recent suffocation of 2 teenagers in Illinois grain elevator. In response to the rising number of workers entrapped and killed in grain storage facilities, OSHA has also issued a new fact sheet, Worker Entry Into Grain Storage Bins (PDF*) in August 2010 for workers and employers emphasizing the hazards of grain storage bin entry and the safe procedures that all employers must follow. Additionally, OSHA issued a safety and health information bulletin (SHIB) entitled, Combustible Dust in Industry: Preventing and Mitigating the Effects of Fire and Explosions, and a Hazard Alert: Combustible Dust Explosions (PDF*) fact sheet.The control of worker's exposure to hazards in grain handling facilities are addressed in the OSHA standard for grain handling facilities (29 CFR 1910.272), as well as in other general industry standards. These standards reduce the risk to workers by requiring that employers follow established, common sense safety practices when working in grain handling facilities.
When workers enter storage bins, employers must (among other things):
- Turn off and lock out all powered equipment associated with the bin, including augers used to help move the grain, so that the grain is not being emptied or moving out or into the bin. Standing on moving grain is deadly; the grain can act like "quicksand" and bury a worker in seconds. Moving grain out of a bin while a worker is in the bin creates a suction that can pull the workers into the grain in seconds.
- Prohibit walking down grain and similar practices where an employee walks on grain to make it flow.
- Provide all employees a body harness with a lifeline, or a boatswains chair, and ensure that it is secured prior to the employee entering the bin.
- Provide an observer stationed outside the bin or silo being entered by an employee. Ensure the observer is equipped to provide assistance and that their only task is to continuously track the employee in the bin. Prohibit workers from entry into bins or silos underneath a bridging condition, or where a build-up of grain products on the sides could fall and bury them.
- Train all workers for the specific hazardous work operations they are to perform when entering and working inside of grain bins.
- Test the air within a bin or silo prior to entry for the presence of combustible and toxic gases, and to determine if there is sufficient oxygen.
- If detected by testing, vent hazardous atmospheres to ensure that combustible and toxic gas levels are reduced to non hazardous levels, and that sufficient oxygen levels are maintained.
- Ensure a permit is issued for each instance a worker enters a bin or silo, certifying that the precautions listed above have been implemented.
- Develop and implement a written housekeeping program with instructions to reduce dust accumulations on ledges, floors, equipment and other exposed surfaces.
- Identify "priority" housekeeping areas in grain elevators. The "priority" housekeeping areas include floor areas within 35 feet of inside bucket elevators, floors of enclosed areas containing grinding equipment and floors of enclosed areas containing grain dryers located inside the facility. Dust accumulations in these priority housekeeping areas shall not exceed 1/8th inch. Employers should make every effort to minimize dust accumulations on exposed surfaces since dust is the fuel for a fire or explosion, and it is recognized that a 1/8 inch dust accumulation is more than enough to fuel such occurrences.
- Inside bucket elevators can undergo primary explosions. OSHA's grain handling standard requires that belts for these bucket elevators purchased after March 30, 1988 are conductive and have a surface electrical resistance not exceeding 300 megohms. Bucket elevators must have an opening to the head pulley section and boot section to allow for inspection, maintenance, and cleaning. Bearings must be mounted externally to the leg casing or the employer must provide vibration, temperature, or other monitoring of the conditions of the bearings if the bearings are mounted inside or partially inside the leg casing. These bucket elevators must be equipped with a motion detection device which will shut-down the elevator when the belt speed is reduced by no more than 20% of the normal operating speed.
- Implement a preventative maintenance program with regularly scheduled inspections for mechanical and safety control equipment, which may include heat producing equipment such as motors, bearings, belts etc. Preventive maintenance is critical to controlling ignition sources. The use of vibration detection methods, heat sensitive tape or other heat detection methods can help in the implementation of the program.
- Minimize ignition sources through controlling hot work (electric or gas welding, cutting, brazing or similar flame producing operations).
- Install wiring and electrical equipment suitable for hazardous locations.
- Design and properly locate dust collection systems to minimize explosion hazards. All filter collectors installed after March 1988 shall be located outside the facility or located in an area inside the facility protected by an explosion suppression system or located in an area that is separated from other areas by construction having at least a one hour fire resistance rating and which is located next to an exterior wall vented to the outside.
- Install an effective means of removing ferrous material from grain streams so that such material does not enter equipment such as hammer mills, grinders and pulverizers.