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Free STSC Practice Questions

10 free, exam-style Safety Trained Supervisor Construction (STSC) practice questions with answers and explanations. No signup required. Work through them below, then take the full free STSC practice test to study every exam domain.

Question 1

An investigation reveals that a worker fell because the safety harness lanyard was not attached to an anchorage. The immediate cause is the unattached lanyard. To find the ROOT cause, the investigator should ask:

  1. Why was the lanyard not attached?
  2. Who should be disciplined for this failure?
  3. How much will this cost the company?
  4. How quickly can we resume work?
Show answer & explanation

Correct answer: A - Why was the lanyard not attached?

Question 2

Atmospheric testing for a confined space entry must test for which gases in which ORDER?

  1. Toxic gases first, then oxygen, then combustibles
  2. Oxygen first, then combustible gases (LEL), then toxic gases
  3. Combustibles first, then oxygen, then toxics
  4. Any order is acceptable as long as all three are tested
Show answer & explanation

Correct answer: B - Oxygen first, then combustible gases (LEL), then toxic gases

Question 3

Benching is an acceptable protective system for which soil types?

  1. All soil types including Type C soils
  2. Type C and unstable soil conditions only
  3. Type A and Type B only
  4. Type A soils and rock formations only
Show answer & explanation

Correct answer: C - Type A and Type B only

Question 4

If oxygen levels in a confined space read 17.5%, this indicates:

  1. Normal atmospheric conditions - entry is safe with standard PPE
  2. A slightly low but acceptable oxygen level for brief work periods
  3. An oxygen-enriched atmosphere requiring ventilation before entry
  4. An oxygen-deficient atmosphere - DO NOT enter without supplied air
Show answer & explanation

Correct answer: D - An oxygen-deficient atmosphere - DO NOT enter without supplied air

Question 5

A crane operator notices the load chart indicates the planned lift exceeds the crane's capacity at the required radius. The operator should:

  1. Refuse to make the lift and notify the supervisor
  2. Attempt the lift slowly and carefully
  3. Extend the boom to increase lifting capacity
  4. Remove outriggers to reduce crane weight
Show answer & explanation

Correct answer: A - Refuse to make the lift and notify the supervisor

Question 6

A worker on a roofing project suddenly stops sweating on a 100°F day and appears confused. The supervisor should recognize this as:

  1. Normal fatigue from heat exposure - provide water and allow extended rest in shade
  2. Heat exhaustion symptoms - move to cool area and monitor vital signs closely
  3. A potential sign of heat stroke - thermoregulation may have failed - initiate emergency response immediately
  4. Dehydration effects - encourage fluid intake and reduce work intensity temporarily
Show answer & explanation

Correct answer: C - A potential sign of heat stroke - thermoregulation may have failed - initiate emergency response immediately

Question 7

A worker is exposed to 100 dBA. Using earplugs with an NRR of 29 and the OSHA derating method, the estimated exposure at the ear is:

  1. 71 dBA
  2. 100 dBA
  3. 78 dBA
  4. 89 dBA
Show answer & explanation

Correct answer: D - 89 dBA

Question 8

A fire involving both flammable liquid (paint thinner) and wood packaging materials near an electrical panel would require:

  1. Only a Class A extinguisher
  2. An ABC-rated extinguisher
  3. Only a Class B extinguisher
  4. Only a Class C extinguisher
Show answer & explanation

Correct answer: B - An ABC-rated extinguisher

Question 9

A worker contacts an energized overhead power line and is still in contact with the line. The FIRST action by a coworker is to:

  1. Pull the victim away from the power line with bare hands
  2. Throw water on the victim to ground the electricity
  3. Do NOT touch the victim while they are in contact with the energy source
  4. Use a metal tool to push the wire away
Show answer & explanation

Correct answer: C - Do NOT touch the victim while they are in contact with the energy source

Question 10

A project manager tells the STSC-certified supervisor to allow work to continue near an unprotected trench because shoring materials won't arrive until tomorrow. Which BCSP Code of Ethics principle(s) are MOST relevant?

  1. Only Professional Development and Competence
  2. Only Diversity and Environmental Stewardship
  3. None - this is a scheduling issue, not an ethics issue
  4. Leadership and Integrity
Show answer & explanation

Correct answer: D - Leadership and Integrity

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