Examples
Worked examples
- Is an instance
A lab bench task involving a volatile solvent is redesigned to use a closed-system transfer device instead of open pouring: this is an engineering control, because it isolates workers from the vapor hazard through equipment design rather than relying on a worker to remember a precaution.
- Is an instance
A lab replaces a chlorinated solvent used for glassware cleaning with a non-chlorinated, lower-toxicity alternative that accomplishes the same task: this is substitution, one level above engineering controls, because the hazardous material itself is no longer present rather than merely contained.
Counter-examples
Looks similar, but isn't
- Not an instance
Requiring lab staff to wear nitrile gloves when handling a hazardous chemical is a PPE control, the lowest and least reliable level of the hierarchy, not an engineering or administrative control -- it protects the individual wearer only, only while worn and worn correctly, and does nothing to reduce the hazard itself or protect anyone else in the room.
Editorial commentary
The hierarchy of controls is NIOSH’s five-level framework for choosing how to reduce a workplace hazard, ranked from most to least reliably effective. It is the standard reference framework behind most laboratory risk-assessment and standard-operating-procedure documentation, including CASRAI’s own lab-safety guides.
The five levels, most to least effective
- Elimination — physically remove the hazard from the workplace entirely (e.g., discontinuing a hazardous procedure or process step).
- Substitution — replace the hazard with something less hazardous that accomplishes the same task (e.g., a less toxic solvent).
- Engineering controls — isolate people from the hazard through equipment or workspace design (e.g., fume hoods, biosafety cabinets, machine guards, local exhaust ventilation).
- Administrative controls — change how people work through policy, training, signage, or scheduling (e.g., standard operating procedures, exposure-limiting shift rotation).
- Personal protective equipment (PPE) — protect the individual worker directly (e.g., respirators, gloves, eye protection) as the last line of defense.
Why the order matters
The ranking is not a matter of preference — it reflects how much a control depends on correct, sustained human behavior to work. Elimination and substitution remove the hazard at the source and function regardless of what any individual worker does on a given day. Engineering controls likewise operate independently of behavior once installed and maintained. Administrative controls and PPE, by contrast, only work if a procedure is actually followed or equipment is actually worn correctly every time — which is why they sit at the bottom of the hierarchy and are generally treated as a supplement to higher-level controls, not a substitute for them, in a well-designed lab safety program.
Applying it in a research lab
A thorough job hazard analysis or risk assessment for a lab procedure should work down the hierarchy in order for each identified hazard: first ask whether the hazardous step can be eliminated or the hazardous material substituted, before reaching for engineering controls, and only fall back to administrative controls or PPE for residual risk that the higher levels cannot fully address.
Related CASRAI terms
- Job hazard analysis for lab procedures — the structured process that applies the hierarchy of controls to a specific lab task.
- Risk assessment matrix for laboratory hazards — scoring severity and likelihood ahead of selecting a control from this hierarchy.
- PPE selection for chemical handling in the lab — detail on the lowest, last-resort level of the hierarchy.
- Respiratory protection program for laboratories — a specific administrative-plus-PPE control regime for respiratory hazards.
- Biosafety cabinet — a concrete example of an engineering control in a biological-hazard lab setting.
Machine-readable encodings
Use in your systems
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