Focus Four — Caught-In or Between — OSHA 30 practice questions

Trench protective system required at:

1. 3 feet
2. 5 feet
3. 10 feet
4. Any depth

Answer: B — 5 feet

A/C/D) Wrong. B) Correct — competent person can determine <5 ft if unstable.

A worker is fatally injured when a wall panel being set by a forklift swings and pins him against a stacked pallet. This event is BEST categorized as which of the Focus Four?

1. Struck-by, because the wall panel was in motion when it reached him
2. Electrocution, because powered lifting equipment was involved in the operation
3. Caught-in or between, because he was squeezed between two solid objects
4. Fall, because the panel was being carried at an elevation above him

Answer: C — Caught-in or between, because he was squeezed between two solid objects

C) Correct — the distinguishing feature of caught-in or between is that the injury results from being squeezed, pinched, or crushed between two objects rather than from the impact of a moving object alone. A) Struck-by involves injury from the impact itself, not compression between objects. B) No electrical contact occurred. D) No one fell to a lower level.

Soil classified as 'Type C' is:

1. The most stable soil type
2. Solid rock
3. Frozen ground only
4. The least stable cohesive/granular soil

Answer: D — The least stable cohesive/granular soil

A is reversed (Type A is most stable). B/C are wrong.

Excavated spoil is being piled right at the edge of an open trench so the loader has a short haul. What is the MOST important objection?

1. The pile blocks the operator's view of traffic passing along the street
2. The added weight loads the wall and material can roll back into the trench
3. The pile will have to be rehandled later, adding labor cost to the job
4. The pile keeps the trench box from being lifted out at the end of the shift

Answer: B — The added weight loads the wall and material can roll back into the trench

B) Correct — spoil and other loads must be kept back from the edge, typically at least two feet, because the added weight loads the wall and loose material falls on workers below. A) Sight lines matter but are not the cave-in mechanism. C) Cost is not a safety objection. D) Equipment access is an inconvenience, not the hazard that kills.

Machine guarding under 29 CFR 1910.212 protects against:

1. Caught-in/between and pinch-point injuries from moving parts
2. Electrocution only
3. Heat illness
4. Hearing loss

Answer: A — Caught-in/between and pinch-point injuries from moving parts

Machine guarding addresses moving-part hazards.

Daily trench inspection by:

Competent person — before workers enter + after rain/water accumulation/changing conditions.

Protective systems for trenches?

Sloping (cut back at angle), benching (steps), shoring (supports), shielding (trench box). Type depends on soil + depth.

When must a competent person inspect an excavation?

Daily before each shift, as needed during the shift, and after every rainstorm or other hazard-increasing occurrence. Workers must be removed if a hazard is found.

Name the three general methods of protecting workers in an excavation.

Sloping or benching the sides • Shoring to support the walls • Shielding with a trench box. Benching is not permitted in Type C soil.