MN FACE Investigation 02MN040
Date: February 26, 2003


Farm Worker Dies After Being Engulfed In Corn Inside A Steel Grain Bin


SUMMARY

An 18-year-old male farm worker (victim) died after he was engulfed in corn inside a steel bin. The bin was equipped with a ventilation fan to aerate grain stored in the bin. It was not turned on at the time of the incident. The bin had one roof access hatch that could be reached from an exterior bin ladder. The bin had a roof ladder adjacent to the access hatch that enabled a worker to sit on the roof next to the access hatch. The bin was equipped with an unloading auger in the floor of the bin. It extended from one side of the bin to the center of the bin floor where there was an intake opening. There was a second intake opening about six feet from the edge of the bin. At the time of the incident, the center auger intake was closed and grain was flowing into the auger via the intake near the edge of the bin. The bin contained about 35,000 bushels of corn at the time of the incident. The victim and another worker were transferring corn from the bin to a raised holding bin at the site. While corn flowed from the bin the victim climbed the exterior bin ladder and opened the access hatch located on the bin roof. The coworker was not aware that the victim had opened the roof hatch and while he concentrated on the task of filling the holding bin, he lost track of the victim. After the holding bin was filed, the coworker realized that the victim was no longer around. He thought that the victim may have left the area for a lunch break since it was nearly noon. After lunch, the coworker asked if anyone had seen the victim. When they were unable to find him, they assumed he might be in the bin and called emergency personnel who arrived shortly after being notified. They began to empty the bin by cutting holes in it. About six hours later the victim's body was found inside the bin. He was removed from the bin and pronounced dead at the scene. MN FACE investigators concluded that, in order to reduce the likelihood of similar occurrences, the following guidelines should be followed:

 

INTRODUCTION

On October 8, 2002, the MN FACE program was notified of a farm work-related fatality that occurred on September 24, 2002. The county sheriff's department was contacted and a copy of their information about the incident was obtained. A site investigation was conducted by a MN FACE investigator on February 6, 2003. During MN FACE investigations, incident information is obtained from a variety of sources such as Minnesota OSHA, law enforcement agencies, county coroners and medical examiners, employers, coworkers and family members. The employer associated with this incident was a grain farmer who had been a farmer for about 30 years. He had grown up on his farm which was previously owned and operated by his father. His farming operation included approximately 2000 acres on which he grew corn and soybeans. He also owned and operated his own basic grain elevator operation on his farm. He employed nine full-time employees and several seasonal employees. The full-time employees consisted of 3 office staff, 3 semi-truck drivers, 2 grain elevator workers and one farm worker. During the growing season he also employed an additional 2-3 seasonal workers. The victim was an 18-year-old youth who had grown up in a small rural town located about 4 miles from the farm. He was hired as a seasonal worker and the day of the incident occurred was only his second day of employment for the farm owner. Training for the farm and grain elevator workers was informal and consisted of on-the-job training by experienced full-time workers.

 

INVESTIGATION

On the day of the incident, the victim and a coworker were removing corn from a steel grain bin. The bin was located on a farm and was part of a grain handling and storage system for corn and soybeans. The grain storage system consisted primarily of 12 steel grain bins, each with a capacity of 48,000 bushels. The bins were situated in two groups of six with each group arranged in two adjacent rows of three bins. Grain could be removed from the bins via an auger mounted in the floor of each bin. The unloading augers transferred grain to one of two long augers in concrete troughs that were located between the rows of three bins. The long augers moved the grain to a below ground grain pit equipped with a vertical elevator to lift the grain and deposit it in a raised holding bin. Semi-trucks were driven under the raised holding bin and filled by opening a door at the bottom of the holding bin which allowed grain to flow into the truck box.

The bin in which the victim was engulfed was 48 feet in diameter, its sides were 27 feet high and it had a capacity of 48,000 bushels. The bin was approximately 30 years old and was equipped with a ventilation fan to aerate stored grain by forcing air into the bottom of the bin. The air was forced upward through the grain and escaped through seams in the bin roof. The fan was not turned on at the time of the incident.

The bin had one access hatch located at the edge of the roof that could be reached from an exterior ladder attached to the side of the bin. The bin had a roof ladder that could be accessed by climbing the exterior bin ladder. The roof ladder was located adjacent to the access hatch and enabled a worker to sit on the roof next to the access hatch. The bin also had an interior ladder fastened to the inside of the bin directly below the access opening. The interior ladder extended to within about 2 feet of the bin floor. The bin also had a side access door that was approximately 30 inches square. It was fitted with a hinged exterior door that opened outward and a hinged interior door that opened in toward the center of the bin.

The bin was equipped with an 8 inch diameter auger mounted horizontally in the concrete base of the bin. It extended from one side of the bin to the center of the bin floor where there was a 10 inch by 12 inch auger intake opening. There was a second auger intake opening about 10 inches square located approximately six feet from the edge of the bin. Both auger intake openings were fitted with steel grates that allowed grain to flow into the auger but prevented workers from being exposed to the augers. Each auger intake also had a horizontal steel cover that could be slid to open and close the intake. The covers were controlled from the outside of the bin by a pipe and rod mechanism that allowed each cover to be opened independently. At the time of the incident, the center auger intake was closed and grain was flowing into the auger via the intake located about six feet from the edge of the bin. When operating, the auger was capable of moving approximately 2500 bushels of grain per hour.

The steel bin contained approximately 35,000 bushels of corn at the time of the incident. It had been filled approximately a year before the incident with corn that was grown and harvested in 2001. The corn was in fair to good condition and did not contain clumps of spoiled corn that would clog the auger intake grates. The grain had recently been sold and was being removed from the bin at the time of the incident. The victim and another worker were transferring corn from the bin to the raised holding bin at the time of the incident. While corn flowed from the bin the victim, for unknown reasons, climbed the exterior bin ladder and opened the access hatch located on the bin roof. The coworker was not aware that the victim had opened the roof hatch and while he concentrated on the task of filling the holding bin, he lost track of the location of the victim. After the holding bin was filed, the coworker stopped the grain augers and realized that the victim was no longer around. He thought that the victim may have left the area and since it was close to noon he thought the victim may have left the area for lunch.

After lunch, the coworker asked if anyone had seen the victim since before noon. When it was discovered that he was missing, they initially searched the entire farm site. When they were unable to find him, they assumed that he might be in the bin and called emergency personnel. Emergency personnel arrived shortly after being notified and began to empty the grain bin by cutting holes in it. They cut ten holes in the sides of the bin to allow corn to pour out. Rescue and farm workers used shovels, skid loaders and a pay loader to move corn away from the bin as the rescue attempt turned into a recovery effort. Approximately six hours after rescue personnel arrived, the victim's body was found near the auger intake located six feet from the edge of the bin. They removed him from the bin and he was pronounced dead at the scene.

 

CAUSE OF DEATH

The cause of death listed on the death certificate was suffocation due to immersion in grain (corn).

 

RECOMMENDATIONS/DISCUSSION

Recommendation #1:Workers should not position themselves near grain bin access openings while a bin is being filled or emptied.

Discussion: Workers may fall into grain bins whenever they climb to uncovered access openings in the bin roof. If a worker near an access opening accidentally falls into a bin while it is being filled or emptied, he/she will be exposed to a number of hazards.

A worker inside a bin that is being filled is at risk of being buried and suffocated by the incoming grain. Even greater dangers of suffocation exist when a bin is being emptied. When grain is allowed to flow from the bottom of a bin, a worker inside the bin may be quickly engulfed in the flowing grain. Flowing grain acts similarly to quicksand and may create forces so great that once a worker is waist deep in the grain, he or she will be unable to escape, even with the aid of a safety rope. Typical auger unloading rates are high enough that a worker will be pulled below the surface of the grain in less than one minute.

Also, the lack of adequate ventilation inside a bin usually results in high concentrations of dusts as a bin is being filled. Workers not wearing adequate dust masks or respirators will be exposed to these dusts. Exposure to these dusts may have both short- and long-term hazardous health effects.

Because of these hazards, workers should never enter, work inside nor position themselves near access openings of a bin while it is being filled or emptied.

 

Recommendation #2: All equipment used to empty a grain bin should be stopped, and the power source locked out, before workers enter the bin.

Discussion: Workers are exposed to engulfment hazards if they enter or work inside a grain bin while it is being emptied. Typical auger unloading rates are high enough that a worker may be pulled below the surface of the grain in less than 15-20 seconds. Because of these hazards, workers should never enter or work inside a bin when it is being emptied. In addition, all power sources should be locked out to ensure that unloading equipment cannot start accidentally or be started inadvertently by someone else. This may require locking out all electrical circuits that operate electric motors, removing ignition keys from tractors or removing spark plug wires from┐ gasoline engines.

 

Recommendation #3: Workers should follow established confined space entry procedures when entering grain bins.

Discussion: If entrance into a grain bin is necessary, workers should follow established confined space entry procedures such as those described in NIOSH Publication No. 80-106. Anyone entering a bin should wear a safety belt or harness and a lifeline that is attached to a fixed external anchor point in a manner that ensures they will remain above the surface of the stored material. In addition, a standby person should be stationed outside the bin whenever a worker enters a bin. Visual contact and/or audible communication should be maintained between the worker in the bin and the standby person at all times. Details of a rescue must be discussed and understood by the worker and the standby person before entry into a bin occurs.

 

Recommendation #4: Grain bins should be identified as confined spaces and posted with hazard warning signs at all entrances.

Discussion: Grain bins meet the NIOSH definition of a confined space. A space is considered "confined" if it has any one of the following characteristics: (1) limited openings for entry and exit; (2) unfavorable natural ventilation; or (3) is not designed for continuous worker occupancy. Entrance into confined spaces are addressed in NIOSH Publication No. 80-106 (Working in Confined Spaces). Warning signs to alert farm workers of the hazards associated with grain bins should be posted at all entrances. In some areas, signs should be printed in more than one language for workers who might not be able to read and understand English.

 

Recommendation #5: Grain bin ventilation fans should be turned on and operating properly before workers enter bins that contain grain.

Discussion: Older grain bins typically were not equipped with ventilation fans but many grain bins built in recent years are equipped with electric ventilation fans. These fans are used primarily to circulate unheated air through the stored grain. Ventilation fans force outside air into a space between the concrete bin foundation and a raised steel floor containing small holes. The air is forced upward through the grain and escapes through seams in the bin roof. When ventilation fans are operating, they are capable of providing a flow of air through the stored grain. Although this flow of air is small, it may prevent a buried worker from suffocating if the worker is located within a short time after being buried in the grain. The presence and use of ventilation fans does not lessen or eliminate the confined space hazards of steel bins nor does their use reduce the need for workers to follow the guidelines provided in Recommendations 1, 2, 3 and 4. However, grain bin ventilation fans should be turned on and operating properly before workers enter bins which are either full or partially full.

 

REFERENCES

  1. NIOSH (1979). Criteria For a Recommended Standard: Working in Confined Spaces. Morgantown, WV: U.S. Department of Health, Education, and Welfare, Public Health Service, Centers for Disease Control, National Institute for Occupational Safety and Health, DHEW (NIOSH) Publication No. 80-106.

 

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