The employer is required by OSHA standards to perform a number of actions to protect workers from caught-in between hazards. Click the button below to see a summary of the requirements.
Moving machine parts have the potential to cause severe workplace injuries, such as crushed fingers or hands, amputations, burns, or blindness. Any machine part, function, or process that may cause injury must be safeguarded.
Different types of hazardous mechanical motions and actions in varying combinations are required to automate tools, equipment, and machinery. Recognizing the hazards they present is the first step toward protecting workers from the danger these motions and actions present. There are three basic hazardous motions and associated actions that can injure employees when exposed.
Click on the button below to see the basic types of hazardous mechanical motions and actions.
Click on the button below to see some examples of reciprocating, rotating, or traversing parts that OSHA requires to be guarded if exposed to contact by workers.
These parts include the movement of rotating members, reciprocating arms, moving belts, meshing gears, cutting teeth, and any parts that impact or shear. These different hazardous mechanical motions and actions are basic in varying combinations to nearly all machines, and recognizing them is the first step toward protecting workers from the danger they present.
For more information on machine safeguarding, see OSHAcademy Course 726, Introduction to Machine Guarding.
1. Which hazardous motion is a push-and-pull motion common to saws?
a. ReciprocatingThe employer must ensure hand-held power tools are fitted with guards and safety switches. The type of guard will be determined by the power source of the tool (electric, pneumatic, liquid fuel, hydraulic, or powder-actuated). Click on the button below to see examples.
Be sure to remove personal protective equipment, loose clothing, and jewelry to prevent being caught by moving parts. Cover your hair because this can also create a hazard. A protective glove can become caught between rotating parts causing multiple serious injuries or death. Long hair can get caught in rotating parts, pulling the worker into the machinery. Jewelry and loose clothing can catch on machine parts causing amputation or serious injury by pulling the hand/body into the machinery.
Use other methods to ensure that machinery is sufficiently supported, secured or otherwise made safe. Make sure your equipment is de-energized and cannot be started accidentally by using lockout/tagout procedures.
Click on the button below to see a list of safe practices to make sure equipment energy sources are controlled.
2. To protect against caught-in between hazards, workers should _____.
a. not wear loose clothing or jewelryThe employer must take measures to prevent workers from being pinned between equipment and a solid object, such as a wall or another piece of equipment; between materials being stacked or stored and a solid object, between shoring and construction materials in a trench.
The best way to prevent workers from being pinned or crushed by heavy equipment that tips over is to prevent the equipment from tipping over in the first place. For example, cranes can tip over if the load capacity is exceeded, or the ground is not level or too soft.
3. The best way to prevent workers from being pinned or crushed by heavy equipment that tips over is to _____.
a. install outriggers when digging trenchesWorkers may be pinned or crushed by equipment, machinery, or structures if parts break, power is lost, or structures become unstable. For instance, a crane boom, scaffold, trench plates, or a wall might unexpectedly collapse.
During demolition, your employer must ensure any stand-alone walls more than one story must have lateral bracing unless the wall was designed to be stand-alone and is otherwise in a safe condition to be self-supporting.
Click on the button below to see what additional measures to take to protect yourself from being pinned between or crushed by equipment, objects, or materials.
Click on the button below to review a pinned-between accident.
Description of the accident
The son of the owner of a commercial drywall construction company, an employee of the company, was preparing an aerial lift for a job and had replaced two battery terminals. He had raised the aerial boom and was reaching toward the battery compartment across the metal enclosure that houses the lift's toggle controls when the boom dropped and pinned him to the control panel. His father discovered him and summoned emergency responders, but he died at the site.
Investigation Findings
The accident resulted in the OSHA violations listed below:
4. During demolition, your employer must ensure non-designed stand-alone walls over one story _____.
a. are surrounded by warning linesYou must be protected from equipment or materials that could fall or roll into excavations. This could include spoils that could fall into the trench and bury the workers. A warning system must be used (such as barricades, hand or mechanical signals, or stop logs), when mobile equipment is:
OSHA standards require, before any worker entry, that employers have a competent person inspect trenches daily and as conditions change to ensure elimination of excavation hazards.
Click on the buttons below to see some important do's and don'ts while working in or around trenches and excavations.
Click on the button below to view a video detailing an actual accident
.5. Which of the following is required if mobile equipment is used near or over an excavation?
a. Horizontal bracing for platesThe type of protection working in trenches 5-20 feet deep may be one of the following:
All simple slope excavations 20 feet (6.11 meters) or less deep should have a maximum allowable slope of 1-1/2:1. A slope of this gradation or less is safe for any type of soil.
Your employer must make sure all excavations and trenches five feet deep or more, but less than 20 feet, are protected by sloping or benching, trench box or shield, or shoring. There must also be an adequate means of access and egress from the excavation. If an excavation is more than 20 feet deep, a professional engineer must design the system to protect the workers.
6. Which of the following protection measures is required for excavations more than 20 feet in depth?
a. Engineered systemMeasures need to be taken by your employer to avoid the collapse of other structures, such as scaffolds, that could bury workers underneath them.
There is a danger of collapse anytime there is inadequate support, improper construction, or a shift in the components of a scaffold (including the base upon which the structure is built). For instance, cinder blocks or other similar materials should not be used to support a scaffold because they could be crushed. To support scaffolds, use only suitable base plates on wood sills.
OSHA standards require that scaffolds can only be erected, moved, dismantled or altered under the supervision of a competent person.
7. Which of the following is suitable for supporting scaffolds so they won't collapse?
a. Base platesOSHA defines a "competent person" as:
"one who is capable of identifying existing and predictable hazards in the surroundings or working conditions which are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them."
Your employer must designate a competent person for certain construction activities that may have caught-in between hazards:
8. Who must train, inspect, and survey safe conditions on most construction sites?
a. A designated managerMake sure you have the proper training on the equipment and hazards of your job so you can work safely. Specific and detailed training is a crucial part of any effort to safeguard employees from worksite hazards.
OSHA’s general training requirement for construction workers is:
The employer shall instruct each employee in the recognition and avoidance of unsafe conditions and the regulations applicable to his work environment to control or eliminate any hazards or other exposure to illness or injury. One way to do this is to review and discuss OSHA Accident Facts.
Your employer must train you to perform your job and use the provided equipment safely. If working with scaffolding your employer should be aware of specific training requirements found in OSHA standards. These standards can be found in 29 CFR 1926.454 (Scaffolds – workers who are involved in erecting, disassembling, moving, operating, repairing, maintaining, or inspecting a scaffold).
9. Providing worker training on the safe use of the equipment being operated is the responsibility of _____.
a. the lead contractorRead the material in each section to find the correct answer to each quiz question. After answering all the questions, click on the "Check Quiz Answers" button to grade your quiz and see your score. You will receive a message if you forgot to answer one of the questions. After clicking the button, the questions you missed will be listed below. You can correct any missed questions and check your answers again.