COSS Industrial Hygiene 2 — Questions and Answers
Question 1: What type of ventilation system captures contaminants at their source before they can disperse into the workplace air?
- General dilution ventilation
- Local exhaust ventilation (LEV) (Correct answer)
- Positive pressure ventilation
- Supply air ventilation
Correct answer: Local exhaust ventilation (LEV)
Local exhaust ventilation (LEV) captures contaminants at or near their source through hoods, ducts, and air-cleaning devices, preventing them from dispersing into the work environment.
Question 2: According to OSHA's Hazard Communication Standard (HazCom), Safety Data Sheets must contain how many sections?
- 8 sections
- 12 sections
- 16 sections (Correct answer)
- 20 sections
Correct answer: 16 sections
OSHA's HazCom 2012 standard, aligned with the Globally Harmonized System (GHS), requires SDSs to contain exactly 16 standardized sections.
Question 3: Which type of industrial hygiene monitoring involves placing a sampler directly on the worker to measure the air they actually breathe?
- Area sampling
- Ambient air monitoring
- Personal sampling (Correct answer)
- Source sampling
Correct answer: Personal sampling
Personal sampling places collection devices within the worker's breathing zone (a 10-inch sphere around the nose and mouth) to measure actual inhalation exposure.
Question 4: Silica dust in the respirable fraction is categorized under which class of industrial hygiene particulates?
- Nuisance dust
- Fibrous particulate
- Fume
- Respirable crystalline silica (Correct answer)
Correct answer: Respirable crystalline silica
Respirable crystalline silica is a specific regulated class of particulate with OSHA-specific PELs (29 CFR 1910.1053) due to its severe lung disease risk including silicosis and lung cancer.
Question 5: What does STEL stand for in occupational exposure limits?
- Standard Time Exposure Limit
- Short-Term Exposure Limit (Correct answer)
- Safe Threshold Exposure Level
- Sustained Time Exposure Level
Correct answer: Short-Term Exposure Limit
STEL (Short-Term Exposure Limit) is the 15-minute TWA concentration that should not be exceeded during any part of the workday, even if the 8-hour TWA is within limits.
Question 6: Which biological effect occurs when a toxic substance reacts with DNA and potentially causes cancer?
- Fibrosis
- Sensitization
- Mutagenesis (Correct answer)
- Narcosis
Correct answer: Mutagenesis
Mutagenesis is the process by which chemicals (mutagens) alter DNA structure; carcinogens are a subset of mutagens that cause mutations leading to cancer.
Question 7: Which factor does NOT affect the rate of skin absorption of a hazardous chemical in an occupational setting?
- Skin integrity and presence of cuts or abrasions
- Molecular weight and lipid solubility of the chemical
- The color of the worker's personal protective equipment (Correct answer)
- Temperature and humidity of the work environment
Correct answer: The color of the worker's personal protective equipment
The color of PPE has no bearing on dermal absorption rates; relevant factors include skin condition, chemical properties, and environmental conditions that affect skin permeability.
