Certified Safety Professional Exam Industrial Hygiene and Exposure Assessment 1 — Questions and Answers
Question 1: What is the OSHA Permissible Exposure Limit (PEL) for silica dust (respirable crystalline silica)?
- 0.05 mg/m³ as an 8-hour TWA (Correct answer)
- 0.1 mg/m³ as an 8-hour TWA
- 0.025 mg/m³ as an 8-hour TWA
- 0.5 mg/m³ as an 8-hour TWA
Correct answer: 0.05 mg/m³ as an 8-hour TWA
OSHA's PEL for respirable crystalline silica is 0.05 mg/m³ as an 8-hour time-weighted average (TWA).
Question 2: Which sampling method is used to determine a worker's full-shift exposure to airborne contaminants?
- Grab sampling
- Personal (full-shift) sampling (Correct answer)
- Area sampling
- Wipe sampling
Correct answer: Personal (full-shift) sampling
Personal full-shift sampling is worn by the worker throughout the shift to accurately represent actual breathing zone exposure.
Question 3: The ACGIH Threshold Limit Value – Short-Term Exposure Limit (TLV-STEL) represents a concentration that workers can be exposed to for how long?
- 5 minutes
- 10 minutes
- 15 minutes (Correct answer)
- 30 minutes
Correct answer: 15 minutes
The TLV-STEL is defined as a 15-minute TWA exposure that should not be exceeded during any part of the workday.
Question 4: What does a hazard ratio (HR) greater than 1.0 indicate in exposure assessment?
- Exposure is within acceptable limits
- Exposure exceeds the occupational exposure limit (Correct answer)
- Additional controls are optional
- The substance is non-hazardous
Correct answer: Exposure exceeds the occupational exposure limit
A hazard ratio greater than 1.0 means the measured exposure exceeds the established occupational exposure limit, requiring corrective action.
Question 5: Which type of industrial hygiene control is considered most effective in the hierarchy of controls?
- Administrative controls
- Personal protective equipment
- Engineering controls – elimination or substitution (Correct answer)
- Work practice controls
Correct answer: Engineering controls – elimination or substitution
Elimination or substitution (engineering controls at the top of the hierarchy) is the most effective way to remove or reduce hazards at the source.
Question 6: What instrument is commonly used to measure noise levels in the workplace for industrial hygiene assessments?
- Spirometer
- Sound level meter / dosimeter (Correct answer)
- Photometer
- Impinger
Correct answer: Sound level meter / dosimeter
A sound level meter measures instantaneous noise, while a dosimeter measures cumulative noise dose over the workshift for IH assessments.
Certified Safety Professional Exam Industrial Hygiene and Exposure Assessment 1
What is the OSHA Permissible Exposure Limit (PEL) for silica dust (respirable crystalline silica)?