FactSheet

Worker Entry into 

Grain Storage Bins 

Engulfment and Suffocation Hazards 

Grain storage bin entry is very dangerous 

and exposes workers to serious suffocation 

hazards - a leading cause of fatalities in this 

industry. Suffocation can occur when workers are engulfed (buried or covered) by grain 

or when bins develop hazardous atmospheres or a lack of oxygen. 

Engulfment can occur when a worker does 

the following: 

• Stands on moving/flowing grain (see figure 1) – The moving grain acts like “quicksand” and buries the worker in seconds. 

• Stands on or below a “bridging” condition 

(see figure 2) - “Bridging” occurs when 

grain clumps together, because of moisture 

or mold, creating an empty space beneath 

the grain as it is unloaded. If a worker 

stands on or below the “bridged” grain, it 

can collapse, either under the worker’s 

weight or unexpectedly, thus, burying the 

worker. 

• Stands next to an accumulated pile of grain 

on the side of the bin (see figure 3) – The 

grain pile can collapse onto the worker 

unexpectedly or when the worker attempts 

to dislodge it. 

The grain’s behavior and weight make it 

extremely difficult for a worker to get out of 

the grain without assistance. Tragically, incidents in grain bins often result in multiple 

fatalities because coworkers attempt rescue 

and fall victim as well. These fatalities are 

preventable if employers follow work practices and provide training and equipment 

as required by OSHA’s Inspection of Grain 

Handling Facilities standard, 29 CFR 1910.272. 

Where Workers Enter Storage Bins, 

Employers Must: 

• De-energize (turn off) and disconnect, lockout and tag, or block off all mechanical, 

electrical, hydraulic and pneumatic equipment that presents a danger, particularly 

grain-moving equipment. Grain must not 

be emptied or moved into or out of the bin 

From the time the In 4-5 seconds After 22 seconds,

auger starts, you

have 2-3 seconds 

you are trapped! you are completely

covered.

to react.

Figure 1. Flowing grain can bury a worker in seconds.

A dangerous situa- As unloading begins, Before the grain

tion created by a bridged grain falls flow can be stopped,

previous partial into the air space the worker is covunloading of the bin. and the worker is ered. In seconds,

instantly trapped. suffocation occurs.

Figure 2. “Bridging” condition that results in engulfment.

Beware of a steep because it may and result in

pile of grain... tumble down... suffocation.

Figure 3. Accumulation on bin side that results in engulfment.

The person on the The person on the The person on the

inside of the bin is roof can pass ground can go for

secured to the out- instructions and help or assist in

side of the bin. assist in lifting. pulling.

Figure 4. Illustration of successful rescue of worker during

“bridging” condition.
while workers are inside because it creates • If toxicity or oxygen deficiency cannot be 

a suction that can pull the worker into the 

grain in seconds. 

• Prohibit walking down grain and similar 

practices where a worker walks on grain to 

make it flow. 

• Prohibit entry onto or below a bridging 

condition, or where grain is built up on the 

side of the bin. 

• Provide each worker entering a bin from a 

level at or above stored grain, or when a 

worker will walk or stand on stored grain 

with a body harness with a lifeline, or a 

boatswain’s chair. Ensure that the lifeline is 

positioned and of sufficient length to prevent a worker from sinking further than 

waist-deep in grain. 

• Provide workers with rescue equipment, 

such as winch systems that are specifically 

suited for rescue from the bin (see figure 4). 

• Station an observer who is equipped to 

provide assistance and perform rescue 

operations outside the bin (see figure 4). 

• Ensure that communications (visual, voice 

or signal line) are maintained between the 

observer and the workers who entered the 

bin. 

• Test the air within a bin for oxygen content 

and the presence of hazardous gases 

before entry. 

• Provide and continue ventilation until 

any unsafe atmospheric conditions are 

eliminated. 

eliminated, workers must wear appropriate 

respirators. 

• Issue a permit each time a worker enters a 

bin, unless the employer is present during 

the entire entry operation. The permit must 

certify that the above precautions have 

been implemented before workers enter 

the bin. 

© 2002, University of Kentucky Cooperative Extension 

Service. Images reproduced with permission. 

Additional Guidance 

• For additional information on safe work 

practices in grain handling facilities, please 

see: 

• 29 CFR 1910.272, Inspection of Grain 

Handling Facilities. 

• OSHA’s Grain Handling Safety and Health 

Topics Page: www.osha.gov/SLTC/ 

grainhandling/index.html. 

• For additional information on safe work 

practices in confined spaces, see 29 CFR 

1910.146, Permit-Required Confined 

Spaces. 

• For additional information on respirators, 

see 29 CFR 1910.134, Respiratory Protection. 

• For additional information on preparing 

young workers to work safely, please visit: 

• www.osha.gov/SLTC/teenworkers/index. 

html, and 

• www.osha.gov/SLTC/youth/agriculture/ 

index.html 

This is one in a series of informational fact sheets highlighting OSHA programs, policies or 

standards. It does not impose any new compliance requirements. For a comprehensive list of 

compliance requirements of OSHA standards or regulations, refer to Title 29 of the Code of Federal 

Regulations. This information will be made available to sensory impaired individuals upon request. 

The voice phone is (202) 693-1999; teletypewriter (TTY) number: (877) 889-5627. 

For more complete information: 

U.S. Department of Labor 

www.osha.gov 

(800) 321-OSHA 

DEP 8/2010