HSE Occupational Health and Hygiene 5 — Questions and Answers
Question 1: When performing a personal air sampling for an 8-hour TWA, where should the sampling pump and filter cassette be positioned on the worker?
- At waist level on the worker's belt
- In the worker's breathing zone, within 12 inches of the nose and mouth (Correct answer)
- On the worker's back between the shoulder blades
- At ankle level to capture floor-level contaminants
Correct answer: In the worker's breathing zone, within 12 inches of the nose and mouth
Personal air samples must be collected in the breathing zone — within approximately 12 inches of the nose and mouth — to accurately represent the air the worker actually inhales.
Question 2: Which type of hazardous substance is most effectively captured by a charcoal adsorption tube during air sampling?
- Metal fumes such as lead and hexavalent chromium
- Volatile organic compounds (VOCs) such as benzene and toluene (Correct answer)
- Mineral dusts such as silica and coal dust
- Asbestos fibers and other elongated mineral particles
Correct answer: Volatile organic compounds (VOCs) such as benzene and toluene
Activated charcoal tubes adsorb volatile organic compounds from sampled air; the compounds are later desorbed and analyzed by gas chromatography.
Question 3: In the context of occupational hygiene, what does 'engineering controls' specifically refer to?
- Written safety programs and standard operating procedures
- Physical modifications to the workplace, equipment, or process to reduce hazard exposure (Correct answer)
- Training workers to recognize and report hazards
- Use of PPE to limit individual exposure
Correct answer: Physical modifications to the workplace, equipment, or process to reduce hazard exposure
Engineering controls are physical or mechanical changes — such as enclosures, LEV systems, substitution, or process changes — that reduce or eliminate the hazard at its source.
Question 4: Whole-body vibration (WBV) is most associated with which occupational health disorder?
- Carpal tunnel syndrome of the wrist
- Low back pain and spinal degeneration (Correct answer)
- Raynaud's phenomenon (vibration white finger)
- Cubital tunnel syndrome of the elbow
Correct answer: Low back pain and spinal degeneration
WBV transmitted through a seat or floor (e.g., heavy equipment operators) is strongly associated with low back pain, disc degeneration, and other spinal disorders.
Question 5: The NIOSH lifting equation recommends a maximum weight limit (RWL) based on six task variables. Which factor, when minimized, most significantly reduces the recommended weight limit?
- Vertical travel distance of the lift
- Frequency of lifts per minute
- Horizontal distance from the body to the object at the start of the lift (Correct answer)
- Asymmetry angle of the trunk during lifting
Correct answer: Horizontal distance from the body to the object at the start of the lift
The horizontal distance (H factor) has the greatest mechanical disadvantage on the spine; doubling H from 10 to 20 inches cuts the RWL in half through its reciprocal relationship in the equation.
Question 6: Under OSHA's Hazard Communication Standard (HazCom/GHS), a Safety Data Sheet (SDS) must contain how many sections?
- 8 sections
- 12 sections
- 16 sections (Correct answer)
- 24 sections
Correct answer: 16 sections
OSHA's HazCom Standard, aligned with GHS, requires SDSs to have exactly 16 standardized sections covering identity, hazards, composition, first aid, fire fighting, and more.
Question 7: A worker exposed to lead at levels exceeding the OSHA action level must be removed from exposure (medical removal protection) when blood lead levels reach which threshold?
- 10 μg/dL
- 30 μg/dL
- 50 μg/dL (Correct answer)
- 70 μg/dL
Correct answer: 50 μg/dL
OSHA's Lead Standard (29 CFR 1910.1025) requires medical removal when a worker's blood lead level reaches 50 μg/dL, with return only after levels fall to 40 μg/dL.
HSE Occupational Health and Hygiene 5
When performing a personal air sampling for an 8-hour TWA, where should the sampling pump and filter cassette be positioned on the worker?