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“Caught in-between” hazards kill workers in a variety of ways. These include: cave-ins and other hazards of excavation work; body parts pulled into unguarded ...
Typology: Schemes and Mind Maps
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This material was produced under grant number SH-16586-07-06-F-36 from the Occupational Safety and Health Administration, U.S. Depart- ment of Labor. It does not necessarily reflect the views or policies of the U.S. Department of Labor, nor does mention of trade names, commercial products, or organizations imply endorsement by the U.S. Government.
MEXERCISEM
What’s Wrong With This Excavation?
Read the story and answer the questions: you should use the fact sheet that follows the story to help you answer the questions.
Union rep Bob Smith called the manager of ABC Company to insist that an unprotected excavating job be shut down immediately. He had received a call from his union safety steward, Jim Riley, about the problems at the site. The day before, Jim complained to his supervisor that a deep trench (about eight (8) feet deep), which was about four (4) feet wide at its base, was not shored (the sides of the trench weren’t supported to prevent a cave-in). The supervisor told Jim to shore it himself, which he tried to do.
When Jim came to work the second day, he saw some of his co-workers working in a second trench, which was also not shored. Excavated material was piled high, right at the edges of both trenches. Both trenches were about eight (8) feet deep. Workers were trying to repair a broken steam line. The steam line had been previously locked out and drained at the power plant supplying the steam.
Within one hour, Bob and an OSHA inspector arrived at the site after the union got management to shut down the job. The union acted because workers were exposed to “imminent danger to life or serious harm” and “the management of ABC Company had refused to cooperate with the union steward’s efforts to do the job safely.”
When the inspection took place, the OSHA inspector found:
✓ the soil content was 87 percent sand ;
✓ the depth of the two excavations was eight ( 8 ) feet, plus the height of the excavated material piled right on the edge;
✓ there was no shoring or other protective system on one of the excavations;
✓ there was inadequate sloping and shoring in the other excavation;
✓ the workers were not trained , and didn’t know how to properly construct shoring or other protective systems.
Unsafe Work: Workers are in a trench more than five (5) feet deep, with no protective system in place.
NQUESTIONSN
1. What happened at this excavation site?
● Employer failed to follow any of the OSHA standards for excavations. Quick action by the steward and the union helped to prevent a serious incident.
2. What were some of the violations of trenching safety?
● No soil classification was done, i.e., the type of soil was not determined ● No competent person when setting up a protective system ● Workers not properly trained to work in an excavation ● No competent person inspecting the excavation before entering
3. What kind of soil type was present at this excavation, and what should this have told the responsible people at the site?
● It was 87 percent sand , Type C soil. This should have told management that the soil was very unstable.
4. What was wrong with the way material was removed from this excavation?
● Material was piled high right at the edge of the trench – it should be at least three feet away. (NOTE: the OSHA standard says it must be at least two feet away; three feet away from the edge is safer.) ● If the soil is piled too close to the side of the trench, it adds weight to an unsupported edge, increasing the likelihood of a cave-in.
5. What training should have been done to protect these workers?
● Only a competent person authorized by the employer can act to correct hazardous conditions at the excavation site. ● All involved workers need training on excavation hazards and how to protect themselves.
b. Trench box or shield: Although these are NOT designed to prevent cave-ins, they should protect workers within the structure if a cave-in occurs.
Trench Box: This worker will be safe as long as he stays inside the trench box while performing his work.
c. Shoring: These are structures built of timber, or they can be mechanical or hydraulic systems, that support the sides of an excavation. Sheeting is a type of shoring that keeps the earth in place.
Shoring: The worker in the excavation is protected by a shoring system. (But watch out for that ladder! It doesn’t extend at least three (3) feet above the top of that wall for safe access and egress.)
● Oxygen-deficient atmospheres can asphyxiate (suffocate) you. You need at least 19.5 percent oxygen. Normal level is 20.9 percent.
● Flammable gases or vapors , that reach a certain concentration known as their Lower Explosive Limit (LEL) , can lead to fires and explosions. In Excavations , you can’t exceed 20 percent of the LEL. (In Confined Spaces – a different standard – it’s 10 percent of LEL.)
● Toxic gases or vapors can poison you, leading to death or serious health problems. Don’t exceed Permissible Exposure Limits (PELs).
Remember, the fatality rate of construction workers killed in unsafe excavations is MORE THAN TWICE the rate for all other construction workers that are killed on the job.
Training Evaluation – Focus 4 Construction Safety & Health
m“CAUGHT IN-BETWEEN” HAZARDSm
❑ Excellent ❑ Good ❑ Fair ❑ Poor
❑ Yes ❑ No ❑ Not sure
❑ Yes ❑ No ❑ Not sure
❑ Yes ❑ No ❑ Not sure
