11/26/2012

Perils of Grain Entrapment

It is the main ingredient of your morning cereal as well as your toast. In fact
grain is the main food of humans and domestic animals. However, these tiny
grains of goodness can also be perilous to the farmers and individuals who work
with them. Over the past thirty years several hundreds of people in Canada and
the United States have died by suffocation after becoming entrapped (caught or
buried) in grain.

The death of three farm workers by grain entrapment and the near miss of a
fourth caused WorkSafe Saskatchewan to issue a hazard alert. Workers who work
with grain - loading, unloading, or moving it - must be aware of the hazards of
flowing grain and ways to prevent becoming entrapped or buried.

There are generally three different ways workers can become caught or trapped
in grain:

1. Collapse of a grain bridge

Mouldy or moist grain can clump together and form a bridge over a hollow cavity
that can collapse under a worker's weight. The worker can fall through and
become buried in and suffocated by an "avalanche" of grain. Anyone standing
under bridged grain is also at great risk of being buried and suffocated as the
bridge can collapse unexpectedly onto them.

2. Collapse of a vertical grain wall

Grain that has spoiled can collect in large vertical columns against the bin
wall. If workers try to break the grain loose, the grain can avalanche down and
completely bury them. The same fate could happen to anyone standing next to a
pile of grain on the side of the bin that suddenly collapses in onto them.

3. Entrapment in flowing grain

Flowing grain - a term used to describe the downward and out movement of grain
from a storage bin - can entrap and bury a person within seconds. When drawn
from below, grain can act like quicksand to entrap and pull a person down. When
flowing from above, grain can bury a person in seconds, especially with high
capacity loading systems. Many entrapments and suffocations have occurred in
high capacity grain transport equipment when victims are either buried during
loading from combine or storage, or drawn into the flow of grain as a vehicle
is being unloaded.

Prevention measures

To reduce the risk of entrapment and suffocation, prevention measures include
the following:


  • Never allow individuals to enter grain bins or grain trucks when loading or unloading grain.

  • Use devices such as a grain bag unloader, auger, or vacuum to enable grains to be unloaded without entering the space.

  • Eliminate the need to enter bins by using proper storage techniques to avoid the grain from spoiling.

  • Use alternate methods to avoid entering a bin, such as using a long stick from outside the bin to break up possible grain bridges.

  • Take precautions to prevent falling into bins. Do not overreach into bin openings.

  • Ensure individuals are aware of all grain entrapment hazards and tag these enclosed spaces with warnings of potential injury.

  • Lockout power to all grain handling equipment to prevent it from unexpected starting up. Grain should not be emptied or moved into or out of the bin while workers are inside as it creates a suction that can pull the worker into the grain in seconds.

  • Take precautions to avoid being entrapped. Break up bridges before entry. Never stand below or next to piled grain within the space.

  • Never allow children to enter grain storage areas; lock all grain bin access openings and position bin ladders high and out of the reach of curious children.


Grain bins and trucks are hazardous confined spaces and employers and
contractors are required to take specific precautions to protect individuals
who work in or near them. Learn about, and comply with, the occupational safety
and health requirements specific to these hazards, in your province or
territory which include taking these confined space hazard control measures:


  • Establish a written entry and rescue plan and ensure that employees are trained and equipped to implement the plan.

  • Train all workers for the specific hazardous work operations they are to perform when entering and working inside of grain bins.

  • Test the air in the bin for oxygen content and the presence of hazardous gases before entering.

  • Ensure that workers have enough air continuously available to them during entry, and if toxicity or oxygen deficiency cannot be eliminated, have workers wear appropriate respirators.

  • Station a second person as an observer who is equipped to provide assistance and trained in rescue procedures, immediately outside the bin. Ensure that communications (visual, voice or signal line) are maintained between the observer and the workers who entered the bin.

  • If entrance into the space is from the top the person must wear a full body harness and lifeline attached to a mechanical lifting device that can lift the person out.

  • Provide workers with rescue equipment, such as winch systems, that are specifically suited for rescue from the bin.



Further Information


AplusA-online.de - Source: Canadian Centre for Occupational Health and Safety