CIH General 3 — Questions and Answers
Question 1: Which sampling strategy is used to characterize the highest likely exposure a worker experiences?
- Worst-case sampling (Correct answer)
- Random sampling
- Baseline sampling
- Compliance sampling
Correct answer: Worst-case sampling
Worst-case sampling intentionally selects conditions expected to produce maximum exposures for conservative risk assessment.
Question 2: A confined space that contains or has the potential to contain a serious atmospheric hazard is classified as which type?
- Non-permit confined space
- Permit-required confined space (Correct answer)
- Restricted access space
- Limited entry space
Correct answer: Permit-required confined space
OSHA defines a permit-required confined space as one with actual or potential serious safety or health hazards requiring a written entry permit.
Question 3: What does the term 'bioavailability' mean in the context of occupational toxicology?
- The toxicity of a substance to living organisms
- The fraction of an absorbed dose that reaches systemic circulation (Correct answer)
- The rate at which a chemical degrades in the body
- The ability of a substance to penetrate skin
Correct answer: The fraction of an absorbed dose that reaches systemic circulation
Bioavailability is the proportion of an administered substance that enters circulation and can exert biological effects.
Question 4: In industrial hygiene statistics, what does the geometric mean better represent compared to the arithmetic mean for lognormally distributed exposure data?
- The highest exposure value
- The central tendency of right-skewed data (Correct answer)
- The variability in exposure measurements
- The regulatory compliance threshold
Correct answer: The central tendency of right-skewed data
Airborne exposure data are typically lognormally distributed, and the geometric mean better represents the central tendency of such skewed datasets.
Question 5: Which route of entry is generally considered the most significant pathway for occupational chemical exposure?
- Dermal absorption
- Ingestion
- Inhalation (Correct answer)
- Injection
Correct answer: Inhalation
Inhalation is typically the most important route because workers continuously breathe workplace air containing contaminants.
Question 6: NIOSH recommends a REL as a TWA for up to how many hours per day?
- 6 hours
- 8 hours (Correct answer)
- 10 hours
- 12 hours
Correct answer: 8 hours
NIOSH RELs are based on a 10-hour TWA for up to a 40-hour workweek, but the standard comparison is the 8-hour workday.
Question 7: An industrial hygienist measures a noise level of 95 dBA. According to OSHA, what is the maximum permissible daily exposure duration?
- 1 hour
- 2 hours (Correct answer)
- 4 hours
- 8 hours
Correct answer: 2 hours
OSHA's permissible noise exposure table allows 2 hours at 95 dBA using the 5 dB exchange rate.
CIH General 3
Which sampling strategy is used to characterize the highest likely exposure a worker experiences?