How to use the drill
Each set runs all 20 scenarios in a shuffled order, with the four controls shuffled too. A ranking scenario says every control is workable on that job, so rank them by level alone: give the most effective a 1 and the least a 4. A pick scenario says what the job rules out, such as an owner keeping skylights or a tool that does not exist, so cross those off and choose the highest level left. The hint points to the rule and the way to think, not the answer.
After you check an answer you see every control in order with its level and why it sits there, the idea the scenario teaches and the 29 CFR 1926 section that applies. The two lifting and posture scenarios have no single section, because Part 1926 has no ergonomics standard. At the end you get your score by hazard, your score by level and the guide to study for your weakest hazard. Hit New shuffle for a fresh order, and quote the set number if you report an error.
The five levels with construction examples
| Level | What it does | Construction example |
|---|---|---|
| Elimination | Removes the hazard or the need to be near it | Assemble a frame on the ground instead of at a roof edge |
| Substitution | Swaps in a less hazardous material, tool or method | Cut steel with a cold saw instead of a torch near combustibles |
| Engineering control | Isolates people from the hazard with equipment that works on its own | Guardrail, trench box, wet saw, local exhaust, GFCI |
| Administrative control | Changes how, when or by whom the work is done | Permits, spotters, rotation, inspections, training |
| PPE | Protects one wearer while the hazard stays | Respirator, hearing protection, harness |
Worked example: masonry above a walkway
Bricklayers are working from a scaffold 20 ft above a covered walkway that staff use all day. The walkway cannot be closed, and a canopy can be fixed over it. Step 1: cross off what the job rules out. Closing the walkway or keeping the area below clear is out, because people have to pass, so the exposure cannot be removed. Step 2: take the highest level left. A canopy or debris net over the walkway is an engineering control that catches falling bricks and tools whether or not anyone notices, and 1926.451(h) calls for falling object protection for people below a scaffold. Step 3: place the rest. A spotter who warns pedestrians is administrative and depends on being seen and heard in time. Hard hats are PPE and do little against a brick from that height. For the soil and slope side of trenching, try the trench sloping calculator.
Three traps the drill is built around
- A required control is not always the strongest. A confined space permit or a backing spotter can be the legal minimum and still rank below a design change that removes the exposure.
- Two compliant options can sit at different levels. A GFCI and an assured grounding program both satisfy 1926.404(b)(1), but the GFCI acts on its own.
- Feasible means on this job. When the top level is ruled out, the answer is the next level that can be done, not PPE by default.
Hierarchy of controls FAQ
What are the five levels of the hierarchy of controls?
From most to least effective: elimination, substitution, engineering controls, administrative controls and personal protective equipment. The top three work without anyone having to remember or choose to use them. The bottom two depend on people following a rule or wearing gear correctly every time, which is why they rank lower.
Why is PPE the last line of defense?
PPE leaves the hazard where it is and puts a layer between it and one person. It works only if it is the right type, fits, is in good condition and is worn the whole time, and it does nothing for anyone nearby without it. It is still needed when the controls above it cannot bring exposure down far enough.
What does strongest feasible control mean?
It is the highest level that can actually be used on this job. If the design, the owner or the work itself rules out elimination, you do not stop there and jump to PPE. You take the next level down that can be done, then add lower layers to cover what is left. Several OSHA construction rules, the noise, lead and silica rules among them, build that order in.
For the health rules behind several scenarios, read OSHA health hazards: silica, lead and noise, and for the open edge and skylight scenarios, fall protection under Subpart M.