CIH Certified Industrial Hygienist (CIH) MCQ 5 — Questions and Answers
Question 1: Which OSHA standard specifically requires employers to implement a written hearing conservation program when noise exposures equal or exceed what action level?
- 85 dBA TWA (Correct answer)
- 90 dBA TWA
- 80 dBA TWA
- 95 dBA TWA
Correct answer: 85 dBA TWA
OSHA 29 CFR 1910.95 requires a hearing conservation program when workers are exposed to an 8-hour TWA of 85 dBA or above (the action level).
Question 2: In industrial hygiene sampling, what is the primary purpose of a field blank sample?
- To establish background concentrations in the ambient environment
- To detect contamination introduced during sample handling, transport, or analysis (Correct answer)
- To calibrate the sampling pump flow rate
- To verify that the sampling media has not exceeded shelf life
Correct answer: To detect contamination introduced during sample handling, transport, or analysis
Field blanks are unexposed media treated identically to field samples to detect contamination during collection, handling, shipping, or laboratory processing.
Question 3: A worker handling lead paint removal is required under 29 CFR 1910.1025 to undergo medical removal if blood lead levels reach:
- 25 µg/dL
- 40 µg/dL
- 50 µg/dL (Correct answer)
- 60 µg/dL
Correct answer: 50 µg/dL
OSHA's lead standard mandates medical removal if a worker's blood lead level reaches 50 µg/dL (general industry) to prevent further health effects.
Question 4: Which type of ventilation system is most effective for controlling contaminants generated at a fixed point source close to the worker's breathing zone?
- General dilution ventilation
- Local exhaust ventilation (LEV) (Correct answer)
- Makeup air supply ventilation
- Recirculated air filtration
Correct answer: Local exhaust ventilation (LEV)
Local exhaust ventilation captures contaminants at or near their source before they can disperse into the worker's breathing zone, making it far more effective than dilution ventilation.
Question 5: Raynaud's phenomenon (vibration white finger) is caused by occupational exposure to:
- Whole-body vibration from heavy equipment
- Hand-arm vibration from powered hand tools (Correct answer)
- Extreme cold alone without vibration
- Repetitive motion without vibration
Correct answer: Hand-arm vibration from powered hand tools
Hand-arm vibration syndrome (HAVS), including vibration-induced white finger (Raynaud's phenomenon), results from prolonged use of vibrating hand tools such as jackhammers and chainsaws.
Question 6: The skin notation assigned to a chemical by ACGIH or OSHA indicates that:
- The chemical causes skin irritation or dermatitis
- Dermal absorption can contribute significantly to total body burden (Correct answer)
- The chemical is corrosive to skin and requires gloves
- The substance is classified as a skin carcinogen
Correct answer: Dermal absorption can contribute significantly to total body burden
The 'skin' notation warns that dermal absorption can contribute meaningfully to overall systemic exposure, meaning air monitoring alone may underestimate total dose.
Question 7: Which statistical measure is most appropriate for describing a lognormally distributed occupational exposure dataset?
- Arithmetic mean and standard deviation
- Geometric mean and geometric standard deviation (Correct answer)
- Median and interquartile range
- Mode and range
Correct answer: Geometric mean and geometric standard deviation
Occupational exposure data typically follows a lognormal distribution, making the geometric mean and geometric standard deviation the appropriate descriptive statistics.
CIH Certified Industrial Hygienist (CIH) MCQ 5
Which OSHA standard specifically requires employers to implement a written hearing conservation program when noise exposures equal or exceed what action level?