COHN Ergonomics and Physical Hazards 4 — Questions and Answers
Question 1: An employee works in a boiler room where temperatures regularly exceed 95°F. Which early symptom of heat illness should prompt immediate removal from the environment?
- Mild perspiration and thirst
- Confusion, slurred speech, or cessation of sweating (Correct answer)
- Muscle cramps in the legs
- Mild headache after the first hour
Correct answer: Confusion, slurred speech, or cessation of sweating
Confusion, slurred speech, and anhidrosis (cessation of sweating) are signs of heat stroke — a life-threatening emergency requiring immediate removal and cooling.
Question 2: Which ergonomic risk factor is most strongly associated with thoracic outlet syndrome in assembly workers?
- Repetitive fine finger movements
- Sustained neck flexion and shoulder elevation (Correct answer)
- Whole-body vibration
- Contact stress on the palm
Correct answer: Sustained neck flexion and shoulder elevation
Sustained forward neck flexion with elevated shoulders compresses neurovascular structures in the thoracic outlet, a common posture in certain assembly and sewing tasks.
Question 3: The ACGIH TLV for a continuous noise exposure of 8 hours is 85 dBA. If exposure is at 88 dBA, the permissible exposure time under ACGIH criteria is:
- 8 hours
- 6 hours
- 4 hours (Correct answer)
- 2 hours
Correct answer: 4 hours
ACGIH uses a 3-dB exchange rate, so an increase of 3 dB (from 85 to 88 dBA) halves the permissible exposure time from 8 hours to 4 hours.
Question 4: A COHN evaluates a production line and finds workers using pliers that require high grip force due to a spring return mechanism. The best ergonomic solution is to:
- Teach workers to grip only with fingertips
- Replace with self-opening (low return-force) pliers (Correct answer)
- Have workers wear padded gloves
- Reduce the shift length by 30 minutes
Correct answer: Replace with self-opening (low return-force) pliers
Self-opening pliers eliminate the need to actively open the tool against a spring, significantly reducing cumulative grip force and MSD risk.
Question 5: According to NIOSH, the recommended weight limit (RWL) for a lift is calculated. If the RWL is 20 lbs and the actual load is 40 lbs, the Lifting Index (LI) is:
- 0.5
- 1.0
- 2.0 (Correct answer)
- 4.0
Correct answer: 2.0
LI = Actual Load ÷ RWL = 40 ÷ 20 = 2.0; an LI > 1.0 indicates the task exceeds safe lifting capacity.
Question 6: Ionizing radiation in the workplace is regulated primarily by which federal agency for occupational exposures?
- EPA
- NRC and OSHA jointly (Correct answer)
- NIOSH
- CDC
Correct answer: NRC and OSHA jointly
Occupational ionizing radiation exposure is regulated by the Nuclear Regulatory Commission (NRC) for licensed materials and by OSHA under 29 CFR 1910.1096 for workplace safety.
Question 7: A worker experiences Raynaud's phenomenon triggered by cold and vibration. Which occupational term specifically describes vibration-induced Raynaud's?
- Dead finger
- Vibration white finger (VWF) (Correct answer)
- Occupational Reynaud's reflex
- Vascular carpal tunnel
Correct answer: Vibration white finger (VWF)
Vibration white finger (VWF), also called hand-arm vibration syndrome (HAVS), describes the vascular component of vibration-induced injury causing episodic blanching of fingers.
COHN Ergonomics and Physical Hazards 4
An employee works in a boiler room where temperatures regularly exceed 95°F.
Which early symptom of heat illness should prompt immediate removal from the environment?