CESCO Industrial Hygiene & Exposure Monitoring 1 — Questions and Answers
Question 1: Which organization publishes Threshold Limit Values (TLVs) used as guidelines for airborne chemical exposure in the workplace?
- American Conference of Governmental Industrial Hygienists (ACGIH) (Correct answer)
- Occupational Safety and Health Administration (OSHA)
- National Institute for Occupational Safety and Health (NIOSH)
- American Industrial Hygiene Association (AIHA)
Correct answer: American Conference of Governmental Industrial Hygienists (ACGIH)
ACGIH publishes TLVs annually as voluntary exposure guidelines; OSHA uses legally enforceable Permissible Exposure Limits (PELs), which are different values.
Question 2: The hierarchy of controls for occupational hazards lists which method as the MOST effective way to protect workers?
- Elimination (Correct answer)
- Engineering controls
- Administrative controls
- Personal protective equipment (PPE)
Correct answer: Elimination
Elimination — physically removing the hazard from the workplace — is the most effective control because it permanently removes the risk rather than managing it.
Question 3: An 8-hour time-weighted average (TWA) exposure measurement is used to compare against which OSHA exposure limit type?
- Permissible Exposure Limit (PEL) (Correct answer)
- Short-Term Exposure Limit (STEL)
- Ceiling Limit (C)
- Immediately Dangerous to Life or Health (IDLH)
Correct answer: Permissible Exposure Limit (PEL)
OSHA PELs are 8-hour TWA values; STELs apply to 15-minute exposures and ceiling limits must never be exceeded at any instant.
Question 4: Noise-induced hearing loss is a permanent condition. At what OSHA action level (8-hr TWA) must employers implement a Hearing Conservation Program?
- 85 dBA (Correct answer)
- 90 dBA
- 80 dBA
- 95 dBA
Correct answer: 85 dBA
OSHA's Hearing Conservation Amendment (29 CFR 1910.95) requires a hearing conservation program when employee noise exposure equals or exceeds 85 dBA as an 8-hr TWA.
Question 5: Which sampling method is used to determine personal airborne chemical exposure during a work shift?
- Personal breathing zone (lapel) sampling (Correct answer)
- Area air monitoring at fixed points
- Wipe sampling of surfaces
- Bulk material sampling
Correct answer: Personal breathing zone (lapel) sampling
Personal breathing zone sampling, where a collection device is worn near the nose and mouth, best represents the air a worker actually inhales during a shift.
Question 6: What does the term 'biomonitoring' mean in the context of industrial hygiene?
- Measuring chemical concentrations in biological specimens such as blood or urine (Correct answer)
- Monitoring plant growth near industrial sites
- Sampling airborne microorganisms in the workplace
- Testing PPE effectiveness in laboratory conditions
Correct answer: Measuring chemical concentrations in biological specimens such as blood or urine
Biomonitoring assesses actual internal dose by measuring the chemical or its metabolites in biological specimens, reflecting absorbed exposure from all routes.
CESCO Industrial Hygiene & Exposure Monitoring 1
Which organization publishes Threshold Limit Values (TLVs) used as guidelines for airborne chemical exposure in the workplace?