CHST General 3 — Questions and Answers
Question 1: Under OSHA 29 CFR 1926, which of the following is the minimum required height for guardrail systems on construction sites?
- 36 inches
- 39 inches
- 42 inches (Correct answer)
- 48 inches
Correct answer: 42 inches
OSHA 1926.502 requires guardrail systems to be 42 inches (plus or minus 3 inches) in height measured from the walking/working surface.
Question 2: A CHST conducting a job hazard analysis (JHA) for concrete formwork discovers workers may be exposed to silica dust. Which OSHA standard primarily governs silica exposure in construction?
- 29 CFR 1926.55
- 29 CFR 1926.1153 (Correct answer)
- 29 CFR 1926.62
- 29 CFR 1926.200
Correct answer: 29 CFR 1926.1153
29 CFR 1926.1153 is OSHA's Respirable Crystalline Silica Standard for construction, establishing PELs and required controls.
Question 3: What does the acronym 'PDCA' stand for in the context of safety management systems?
- Plan, Design, Control, Audit
- Plan, Do, Check, Act (Correct answer)
- Prepare, Deploy, Confirm, Assess
- Process, Document, Correct, Archive
Correct answer: Plan, Do, Check, Act
PDCA (Plan, Do, Check, Act) is the continuous improvement cycle foundational to safety management systems like ANSI/ASSP Z10.
Question 4: When evaluating a construction site's safety program, a CHST finds the experience modification rate (EMR) is 1.35. What does this indicate?
- The company has 35% fewer injuries than average
- The company's workers' comp costs are 35% above industry average (Correct answer)
- The company is exempt from OSHA inspections
- The company qualifies for safety incentive bonuses
Correct answer: The company's workers' comp costs are 35% above industry average
An EMR above 1.0 indicates a worse-than-average injury history; 1.35 means costs are approximately 35% higher than the industry average.
Question 5: Which type of fire extinguisher is appropriate for energized electrical equipment fires on a construction site?
- Class A
- Class B
- Class C (Correct answer)
- Class D
Correct answer: Class C
Class C extinguishers use non-conductive agents suitable for energized electrical equipment fires.
Question 6: Under OSHA's excavation standard (29 CFR 1926 Subpart P), how soon after a hazardous atmosphere is detected must workers be evacuated from an excavation?
- Within 30 minutes
- Within 15 minutes
- Immediately (Correct answer)
- After the competent person performs a second test
Correct answer: Immediately
OSHA requires immediate evacuation of workers when a hazardous atmosphere is detected in an excavation until the hazard has been eliminated.
Question 7: A safety technician is reviewing incident records and calculates a Days Away, Restricted, or Transferred (DART) rate of 4.5. How is this rate expressed?
- Per 100 workers per year
- Per 200,000 hours worked (Correct answer)
- Per 1,000,000 hours worked
- Per 50 employees
Correct answer: Per 200,000 hours worked
OSHA injury/illness rates including DART are calculated per 200,000 hours worked, which represents 100 full-time equivalent employees working one year.
CHST General 3
Under OSHA 29 CFR 1926, which of the following is the minimum required height for guardrail systems on construction sites?