EdCircuit Staff 
The hierarchy of controls in schools helps educators reduce hazards at the source before relying on personal protective equipment as the final layer of protection.
A science teacher has spent days preparing a laboratory activity. The materials are labeled. Students have goggles, gloves, and aprons. Procedures have been reviewed, and waste containers are ready.
Then the ventilation monitor signals a problem.
Everyone may be wearing the required PPE, but goggles and gloves cannot remove hazardous vapors from the room. The teacher now faces a decision that reveals the difference between being equipped and being protected: continue because students have PPE, or change the lesson because a stronger safety control is unavailable?
That question is at the center of the latest episode of Safer Ed, “Safety by Design: Why PPE Is the Last Line of Defense.” The episode examines why effective safety begins before an activity starts—and why protective equipment should never compensate for a hazard that could have been removed, replaced, or isolated.
PPE Is Visible. Stronger Controls Often Are Not.
When people picture safety in a laboratory, workshop, art room, kitchen, or athletic space, they often picture goggles, gloves, face shields, aprons, or protective footwear.
PPE is visible. It can be counted, distributed, inspected, and added to a supply list. That visibility can make it feel like the foundation of a safety program.
It is not.
PPE reduces exposure when a hazard remains. Its effectiveness depends on selecting the correct equipment, providing the right fit, teaching people how to use it, maintaining it, and ensuring it is worn consistently. Each step introduces another opportunity for failure.
The strongest safety systems control the hazard before it reaches the person.
Understanding the Hierarchy of Controls
The National Institute for Occupational Safety and Health organizes hazard controls into five levels, from generally most effective to least effective:
Elimination
Substitution
Engineering controls
Administrative controls
Personal protective equipment
The model comes from occupational safety, but its logic translates directly to schools. Most activities require several controls working together. The hierarchy helps schools begin with the protections that depend least on perfect human behavior.
1. Eliminate the Hazard
Elimination removes a hazard from the activity or environment.
In a school, that might mean removing an unnecessary chemical, taking damaged equipment out of service, avoiding an open flame when heat is not essential, or discontinuing a demonstration whose instructional value does not justify its risk.
Elimination does not mean removing meaningful challenge. It means asking whether the hazard contributes to the learning. If students can meet the same objective without it, the strongest control may be changing the activity—not adding another warning.
2. Substitute Something Safer
When a hazard cannot be eliminated, a safer material, tool, or process may accomplish the same goal.
A solvent-based product may have a less hazardous alternative. A high-energy tool may be replaced with equipment better suited to students’ experience. A demonstration may be redesigned on a smaller scale to reduce the amount of hazardous material involved.
Substitution still requires evaluation. A product described as “safer” may create a different hazard or require new storage and disposal procedures. The entire activity—not only the replacement product—must be reviewed.
3. Build Protection Into the Space or Equipment
Engineering controls isolate people from hazards through the design of the room, equipment, or process. Examples include local exhaust ventilation, fume hoods, machine guards, splash shields, barriers, safety interlocks, and dust collection.
These controls work at the source. A functioning guard does not depend on a student remembering exactly where to place a hand. Proper ventilation captures contaminants before they spread through the room.
But an engineering control protects people only when it works. The sound of a fan does not prove that a ventilation system is performing correctly. A guard that has been removed, bypassed, or poorly fitted is no longer providing its intended protection.
Maintenance and testing may fall outside a teacher’s direct responsibility. Facilities teams, administrators, department leaders, and safety personnel all influence whether a room can support an activity safely.
4. Establish Procedures People Can Follow
Administrative controls change how people work. They include training, procedures, supervision, scheduling, signage, restricted access, and inspections.
Schools rely on these controls every day. Teachers demonstrate procedures. CTE instructors control access to machinery. Coaches establish practice rules. Custodial teams follow protocols for handling products and equipment.
Administrative controls matter, but they depend on people and conditions. A procedure is less reliable when a room is overcrowded, supervision is divided, materials are poorly placed, or the schedule creates pressure to rush. A rule that cannot be followed under real conditions is not an effective control.
5. Match PPE to the Remaining Risk
PPE protects the person when hazards remain after stronger controls have been applied. It may include goggles, gloves, protective clothing, face shields, hearing protection, or respiratory protection selected for a specific hazard and task.
Calling PPE the last line of defense does not make it optional. It means PPE should not be asked to do the work of a stronger control.
Safety glasses do not replace a machine guard. Gloves do not replace proper chemical handling or containment. A lab coat does not correct a failed ventilation system.
PPE also must fit the people expected to use it. Equipment that is damaged, poorly sized, incompatible with other equipment, or inaccessible to a student may provide less protection than the school assumes. OSHA’s PPE guidance emphasizes proper fit, training, maintenance, and continued program review.
When a Control Fails, the Activity Must Change
Return to the laboratory with the ventilation warning.
Opening a classroom door is not an automatic substitute for functioning local exhaust ventilation. Adding more PPE does not repair the system. Asking students to work quickly only adds time pressure to an already compromised situation.
If an activity depends on a control that is unavailable, the lesson should change or wait until the control is restored.
Teachers need clear authority to make that decision. They also need confidence that pausing an activity will be treated as responsible professional judgment—not poor planning or lost instructional time.
A lesson can be rescheduled. An exposure cannot be undone.
Safety Decisions Begin Before Purchasing
The hierarchy should influence purchasing and program planning, not only classroom procedures.
The least expensive item may not produce the lowest-cost safety decision. A chemical may require specialized storage, ventilation, disposal, training, and PPE. A machine may be difficult to guard, expensive to maintain, or unsuitable for the students expected to use it.
Those conditions should be considered before an order is placed. Educators, facilities staff, and employees who will use or maintain the product should be included in the review. OSHA’s hazard-prevention guidance recommends involving the people who understand the work, selecting controls through the hierarchy, and confirming that the controls remain effective.
Beyond the Science Lab
The hierarchy of controls in schools applies wherever students and staff encounter hazards.
In a CTE workshop, guards and dust collection should come before relying on safety glasses alone.
In an art room, less hazardous materials and appropriate ventilation are stronger controls than gloves alone.
In a culinary program, equipment guards, heat barriers, and workspace design can prevent contact before protective clothing is needed.
In athletics, removing damaged equipment or changing an unsafe drill may be more effective than another reminder to “be careful.”
In facilities operations, safer products and improved dispensing or ventilation systems can reduce dependence on PPE and procedural reminders.
The setting changes. The central question does not: Can the hazard be controlled before it reaches the person?
Five Questions to Ask Before an Activity
Schools can apply the hierarchy with a short review:
What hazards are present, and can any be removed?
Can a safer material, tool, or process be used?
Can equipment, ventilation, guards, or barriers isolate the hazard?
What procedures, training, supervision, and PPE are still necessary?
What happens if a required control is unavailable or fails?
These questions belong in lesson planning, purchasing, facilities reviews, professional learning, and program design. They are far more useful before students enter the room than while they are waiting for instructions.
Listen to Safer Ed
In “Safety by Design: Why PPE Is the Last Line of Defense,” Safer Ed explores how schools can move beyond visible compliance and build safety into activities, equipment, facilities, and decision-making.
Safer Ed is sponsored by Science Safety and produced in partnership with edCircuit.
Learn More
Duty of Care — Explore how educators and school leaders can anticipate foreseeable harm and protect students across school settings.
Hazard Control and Safety — Learn more about identifying hazards, reducing exposure, and building effective control programs.
Personal Protective Equipment (PPE) — Review the selection, use, care, and limitations of PPE in educational environments.
The strongest safety program is not the one with the longest equipment list. It is the one that asks whether a hazard can be removed, reduced, or contained before anyone must rely on the final line of defense.
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