NSC Workplace Safety 4 — Questions and Answers
Question 1: Which of the following is NOT one of the three elements of the fire triangle?
- Heat
- Fuel
- Oxygen
- Pressure (Correct answer)
Correct answer: Pressure
The fire triangle consists of heat, fuel, and oxygen; pressure is not required for combustion.
Question 2: A worker is exposed to 50 ppm of a chemical for 4 hours and 100 ppm for 4 hours. What is the 8-hour TWA?
- 50 ppm
- 75 ppm (Correct answer)
- 100 ppm
- 150 ppm
Correct answer: 75 ppm
TWA = (50×4 + 100×4) / 8 = 600 / 8 = 75 ppm.
Question 3: What is the role of the 'attendant' in a confined space entry operation?
- To perform atmospheric testing inside the space
- To remain outside and monitor the entrant, summoning rescue if needed (Correct answer)
- To supply breathing air to workers inside
- To document work completed inside the space
Correct answer: To remain outside and monitor the entrant, summoning rescue if needed
The attendant stays outside the permit space, monitors entrants continuously, and initiates rescue procedures if an emergency occurs.
Question 4: OSHA's general industry standard requires fall protection when workers are exposed to fall heights of how many feet or more?
- 4 feet (Correct answer)
- 6 feet
- 8 feet
- 10 feet
Correct answer: 4 feet
OSHA 29 CFR 1910.23 requires fall protection in general industry at heights of 4 feet or more.
Question 5: Which OSHA standard gives workers the 'right to know' about chemical hazards in their workplace?
- OSHA 300 Log standard
- Hazard Communication Standard (HCS) (Correct answer)
- National Emphasis Program (NEP)
- Process Safety Management (PSM) standard
Correct answer: Hazard Communication Standard (HCS)
The Hazard Communication Standard (29 CFR 1910.1200) requires chemical labeling and SDS access so workers know about hazards.
Question 6: A yellow diamond on a DOT hazard placard typically indicates which class of material?
- Flammable liquid
- Explosive
- Oxidizer or organic peroxide (Correct answer)
- Corrosive material
Correct answer: Oxidizer or organic peroxide
Yellow DOT placards signify oxidizers or organic peroxides, which can intensify fires by supplying additional oxygen.
Question 7: Which respirator provides the highest level of protection and is used in immediately dangerous to life or health (IDLH) atmospheres?
- Surgical mask
- Half-face air-purifying respirator
- Full-face air-purifying respirator
- Self-contained breathing apparatus (SCBA) (Correct answer)
Correct answer: Self-contained breathing apparatus (SCBA)
An SCBA supplies its own independent air source, giving the highest protection factor and is required in IDLH atmospheres.
NSC Workplace Safety 4
Which of the following is NOT one of the three elements of the fire triangle?