STSC Hazard Recognition and Risk Assessment 4 â Questions and Answers
Question 1: A construction supervisor notices workers repeatedly bypassing a safety guardrail to save time. Which risk assessment step should be prioritized first?
- Immediately retrain all workers on fall protection
- Identify why workers are bypassing the guardrail before imposing penalties (Correct answer)
- Replace the guardrail with a more visible barrier
- Document the violation and submit an incident report
Correct answer: Identify why workers are bypassing the guardrail before imposing penalties
Understanding the root cause of unsafe behavior (e.g., inconvenience, poor placement) is the first step in effective risk assessment to create lasting corrective action.
Question 2: Which hierarchy of controls option is considered most effective when addressing a recognized construction site hazard?
- Administrative controls
- Personal protective equipment
- Engineering controls
- Elimination of the hazard (Correct answer)
Correct answer: Elimination of the hazard
Eliminationâphysically removing the hazardâis the most effective control because it prevents exposure entirely rather than managing it.
Question 3: During a pre-task hazard assessment for excavation work, which document should a supervisor consult to identify underground utility hazards?
- OSHA 300 Log
- Site-specific utility locating (811 dig-safe) records (Correct answer)
- Soil classification report only
- Previous inspection checklists
Correct answer: Site-specific utility locating (811 dig-safe) records
Consulting 811 dig-safe utility locating records before excavation identifies buried lines that pose electrocution, fire, or explosion risks.
Question 4: A Risk Priority Number (RPN) in a Failure Mode and Effects Analysis (FMEA) is calculated by multiplying which three factors?
- Frequency, Exposure, and Consequence
- Severity, Occurrence, and Detectability (Correct answer)
- Likelihood, Impact, and Control effectiveness
- Probability, Severity, and Mitigation cost
Correct answer: Severity, Occurrence, and Detectability
RPN = Severity Ă Occurrence Ă Detectability; a higher RPN indicates a higher priority risk requiring immediate attention.
Question 5: Which condition would classify soil as Type Câthe least stable classificationâduring a trenching hazard assessment?
- Soil with unconfined compressive strength of 1.5 tons per sq ft or greater
- Soil that is fissured, submerged, or previously disturbed (Correct answer)
- Hard rock that requires blasting to excavate
- Cohesive soil with stable layering and no water seepage
Correct answer: Soil that is fissured, submerged, or previously disturbed
Type C soil is fissured, subject to water seepage, previously disturbed, or has an unconfined compressive strength of 0.5 tsf or less, making it the least stable.
Question 6: What is the primary purpose of a Job Hazard Analysis (JHA) in construction?
- To assign blame after an incident occurs
- To document worker certifications and training records
- To systematically identify hazards associated with each task step before work begins (Correct answer)
- To calculate the cost of personal protective equipment for a project
Correct answer: To systematically identify hazards associated with each task step before work begins
A JHA breaks a job into steps, identifies hazards at each step, and establishes controls before work starts to prevent injuries.
Question 7: When conducting a risk assessment, 'residual risk' refers to which of the following?
- The original risk level before any controls are applied
- The risk remaining after all feasible controls have been implemented (Correct answer)
- Risk transferred to a subcontractor through contract language
- The financial liability retained by the general contractor
Correct answer: The risk remaining after all feasible controls have been implemented
Residual risk is the level of risk that remains after controls are in place; supervisors must determine whether it is acceptable before authorizing work.
STSC Hazard Recognition and Risk Assessment 4
A construction supervisor notices workers repeatedly bypassing a safety guardrail to save time.
Which risk assessment step should be prioritized first?