SHS Risk Assessment & Hazard Control 2 — Questions and Answers
Question 1: Which risk assessment methodology assigns numerical scores to likelihood and severity to produce a risk priority number (RPN)?
- Fault Tree Analysis
- Failure Mode and Effects Analysis (FMEA) (Correct answer)
- Job Hazard Analysis
- HAZOP Study
Correct answer: Failure Mode and Effects Analysis (FMEA)
FMEA calculates an RPN by multiplying severity, occurrence, and detectability scores to prioritize corrective actions.
Question 2: Under OSHA's hierarchy of controls, substitution is defined as:
- Adding warning signs near the hazard
- Replacing a hazardous substance with a less hazardous one (Correct answer)
- Isolating workers from the hazard using barriers
- Requiring PPE when near the hazard
Correct answer: Replacing a hazardous substance with a less hazardous one
Substitution involves replacing a hazardous material, process, or equipment with a safer alternative.
Question 3: A 'residual risk' is best described as:
- The initial risk before any controls are applied
- The risk remaining after all controls have been implemented (Correct answer)
- The risk transferred to a third-party contractor
- The maximum acceptable risk level set by OSHA
Correct answer: The risk remaining after all controls have been implemented
Residual risk is the level of risk that persists even after all feasible control measures have been put in place.
Question 4: Which document is used during a Job Hazard Analysis to record each task step, associated hazards, and recommended controls?
- Safety Data Sheet (SDS)
- JHA worksheet (Correct answer)
- Incident investigation report
- Process safety management plan
Correct answer: JHA worksheet
A JHA worksheet systematically breaks a job into steps, identifies hazards at each step, and documents preventive measures.
Question 5: The 'bowtie' risk model visually represents:
- Only the causes of an event on the left side
- Causes on the left, the top event in the center, and consequences on the right (Correct answer)
- Consequences of an event on both sides of a central control
- The cost-benefit ratio of implementing safety controls
Correct answer: Causes on the left, the top event in the center, and consequences on the right
The bowtie model places the hazardous event in the center, with threats/causes branching left and consequences branching right.
Question 6: When conducting a quantitative risk assessment, the probability of an event is typically expressed as:
- A qualitative descriptor such as 'high' or 'low'
- A frequency per unit time (e.g., events per year) (Correct answer)
- A color on a risk matrix
- A categorical ranking from 1 to 5
Correct answer: A frequency per unit time (e.g., events per year)
Quantitative risk assessment uses statistical frequencies (e.g., failures per year) rather than subjective descriptors.
Question 7: Which chemical hazard control involves enclosing a process to prevent worker exposure to airborne contaminants?
- Dilution ventilation
- Local exhaust ventilation
- Complete enclosure (Correct answer)
- Administrative rotation
Correct answer: Complete enclosure
Complete enclosure contains the hazardous process within a sealed system, preventing contaminants from entering the work environment.
SHS Risk Assessment & Hazard Control 2
Which risk assessment methodology assigns numerical scores to likelihood and severity to produce a risk priority number (RPN)?