COHN Ergonomics and Physical Hazards Questions and Answers — Questions and Answers
Question 1: An occupational health nurse is conducting an ergonomic assessment of a workstation for an employee who performs data entry for 8 hours a day. The nurse utilizes the Rapid Upper Limb Assessment (RULA) tool. This tool is MOST appropriate for this task because it specifically evaluates:
- Whole-body postural musculoskeletal risks, including the legs and trunk.
- The maximum acceptable weight for manual material handling tasks.
- Biomechanical and postural load on the neck, trunk, and upper extremities. (Correct answer)
- The risk of developing Hand-Arm Vibration Syndrome (HAVS).
Correct answer: Biomechanical and postural load on the neck, trunk, and upper extremities.
The Rapid Upper Limb Assessment (RULA) tool is specifically designed to assess the biomechanical and postural loads on the upper body, including the neck, trunk, and arms. It is ideal for evaluating sedentary tasks like data entry where the risk is concentrated in the upper extremities. The other options are incorrect: REBA assesses the entire body, the NIOSH Lifting Equation assesses lifting tasks, and HAVS is related to vibration exposure.
Question 2: A manufacturer implements a new process that requires workers to use a handheld pneumatic wrench. After several months, a worker reports intermittent blanching (whitening), numbness, and tingling in their fingers, especially in cold conditions. The occupational health nurse should recognize these symptoms as most characteristic of which physical hazard-related condition?
- Carpal Tunnel Syndrome
- Tendonitis
- Hand-Arm Vibration Syndrome (HAVS) (Correct answer)
- Thoracic Outlet Syndrome
Correct answer: Hand-Arm Vibration Syndrome (HAVS)
Hand-Arm Vibration Syndrome (HAVS), also known as Vibration White Finger, is caused by regular, prolonged exposure to vibrating hand tools. Its characteristic symptoms include vascular effects like finger blanching (Raynaud's phenomenon), neurological effects like numbness and tingling, and musculoskeletal issues. The use of a pneumatic wrench is a common risk factor for HAVS.
Question 3: An occupational health nurse is part of a team tasked with reducing the risk of low back injuries in a warehouse. They are using the Revised NIOSH Lifting Equation to calculate the Recommended Weight Limit (RWL) for a specific lifting task. Which of the following factors is a key variable in this equation?
- The worker's age and gender.
- The ambient temperature of the warehouse.
- The horizontal distance of the load from the worker's body. (Correct answer)
- The worker's pre-existing medical history.
Correct answer: The horizontal distance of the load from the worker's body.
The Revised NIOSH Lifting Equation uses several task-specific variables to determine a Recommended Weight Limit (RWL). One of the most critical is the Horizontal Multiplier (HM), which is based on the horizontal distance of the hands from the midpoint between the ankles (H). The farther the load is held from the body, the lower the RWL will be. The worker's personal characteristics (age, gender, medical history) and ambient temperature are not direct inputs into the equation itself.
Question 4: A company's safety committee, including the occupational health nurse, is reviewing controls for a noisy manufacturing area. They have already provided all affected employees with hearing protection. According to the hierarchy of controls, which of the following actions represents a more effective long-term solution?
- Implementing mandatory annual audiometric testing.
- Rotating employees out of the noisy area every two hours.
- Enclosing the primary noise-producing machine in an acoustic barrier. (Correct answer)
- Posting additional signage requiring the use of hearing protection.
Correct answer: Enclosing the primary noise-producing machine in an acoustic barrier.
The hierarchy of controls prioritizes methods from most to least effective: Elimination, Substitution, Engineering Controls, Administrative Controls, and Personal Protective Equipment (PPE). Enclosing the machine is an engineering control, which physically isolates people from the hazard and is more effective than administrative controls (like job rotation) or relying on PPE (hearing protection), which is the least effective control.
Question 5: According to OSHA's Occupational Noise Exposure standard (29 CFR 1910.95), an employer is required to implement a hearing conservation program when the time-weighted average (TWA) noise exposure equals or exceeds what level?
- 80 dBA over an 8-hour shift
- 85 dBA over an 8-hour shift (Correct answer)
- 90 dBA over an 8-hour shift
- 100 dBA over an 8-hour shift
Correct answer: 85 dBA over an 8-hour shift
OSHA requires employers to implement a hearing conservation program when employee noise exposures equal or exceed the action level of 85 decibels on the A-scale (dBA) as an 8-hour time-weighted average (TWA). The Permissible Exposure Limit (PEL) is 90 dBA, at which point engineering or administrative controls are required.
Question 6: An occupational health nurse is educating a group of assembly line workers on preventing musculoskeletal disorders (MSDs). Which of the following should the nurse identify as a primary ergonomic risk factor?
- Poor indoor air quality
- Inadequate lighting
- High-pressure deadlines
- Awkward postures (Correct answer)
Correct answer: Awkward postures
Primary ergonomic risk factors are conditions of a job that can lead to musculoskeletal disorders. These include forceful exertions, repetition, and awkward or static postures. While factors like deadlines (psychosocial stress), air quality, and lighting are important workplace health and safety concerns, awkward posture directly applies mechanical stress to the musculoskeletal system and is a core ergonomic risk factor.
COHN Ergonomics and Physical Hazards Questions and Answers
An occupational health nurse is conducting an ergonomic assessment of a workstation for an employee who performs data entry for 8 hours a day.
The nurse utilizes the Rapid Upper Limb Assessment (RULA) tool.
This tool is MOST appropriate for this task because it specifically evaluates: