What is a Control Measure?

Understanding Control Measures

Control measures are the fundamental units of workplace safety management. While the Work Health and Safety Act 2011 establishes your primary duty of care, it's the control measure that translates this abstract legal obligation into tangible reality on the shop floor, construction site, or office environment.

Without control measures, your safety management system is merely a collection of aspirations. The control measure is the actual mechanism of protection.

Under the Model WHS Regulations, a control measure is defined as "a measure to eliminate or minimise the risk." This definition encompasses everything from the architectural design of a building to the specific filtration specification of a respirator.

Hazard-Focused vs Risk-Focused Controls

To understand control measures, you must distinguish between the hazard and the risk. Controls can target either, though they are legally preferred to target the hazard directly.

Hazard-focused controls attack the source. Removing a noisy generator (Elimination) or enclosing it in an acoustic booth (Isolation) addresses the hazard (noise energy) directly.

Risk-focused controls mitigate the interaction between the hazard and your workers. Rotating shifts to limit noise exposure duration (Administrative) or issuing earplugs (PPE) manages the risk (hearing loss) without removing the hazard.

The legislative intent, embodied in the Hierarchy of Controls, is to push you toward hazard-focused controls because they're inherently more reliable and less dependent on human vigilance.

The "Reasonably Practicable" Nexus

The selection of a control measure is legally bound by the concept of "reasonably practicable" (Section 18 of the WHS Act). You're not required to implement a control simply because it exists—you must implement it if it's reasonably practicable to do so.

This determination involves weighing five factors:

This framework ensures that control measures are proportionate to the risk. For high-consequence risks like silica dust exposure or falls from heights, the "grossly disproportionate" threshold for cost is extremely high, essentially mandating high-level engineering controls regardless of significant expense.

How Control Measures Work: The Hierarchy Framework

The mechanics of control measures are governed by the Hierarchy of Controls—a regulatory mandate under Regulation 36 of the Model WHS Regulations. The hierarchy ranks control measures from the highest level of protection and reliability to the lowest.

Hard controls (Levels 1-4) rely on physical infrastructure rather than human behavior. Soft controls (Levels 5-6) depend entirely on worker compliance, making them inherently less reliable.

Level 1: Elimination—The Gold Standard

Elimination involves the complete removal of the hazard from your workplace. This is the most effective control because it reduces the risk to zero. Once a hazard is eliminated, no management or supervision is required to ensure safety regarding that specific hazard.

Elimination is most effectively achieved during the design and planning phases. It often involves questioning the necessity of a task or process altogether.

Examples: Installing an automated palletizing robot to remove the need for workers to manually lift 20kg bags eliminates the musculoskeletal risk. Re-engineering a cleaning process to use high-pressure steam instead of a toxic solvent eliminates the chemical hazard entirely. Designing window cleaning mechanisms operable from the ground eliminates the fall hazard.

Elimination is often perceived as expensive upfront but offers the highest return on investment by removing future costs associated with training, PPE, maintenance, and potential injury claims.

Level 2: Substitution, Isolation, and Engineering

If elimination is not reasonably practicable, the WHS Regulations require you to minimise risk through Level 2 controls. These are collectively known as "hard" controls because they rely on physical infrastructure rather than human behavior.

Substitution

Substitution replaces a hazardous substance, plant, or work method with one that is less hazardous. The function remains, but the risk profile is lowered.

Examples: Replacing solvent-based paints with water-based paints reduces flammability and toxicity risks. Using 24V cordless tools instead of 240V mains power tools in damp environments reduces electrocution risk. Replacing heavy packaging material with a lighter alternative reduces manual handling strain.

Isolation

Isolation involves physically separating the hazard from the person, either by distance or by a physical barrier. It prevents contact without removing the hazard.

Examples: Installing concrete jersey barriers to separate forklift traffic from pedestrian walkways. Placing a noisy compressor inside an acoustic enclosure. Using remote-controlled demolition robots to keep operators away from falling debris or dust. Storing flammable liquids in a dedicated, fire-rated cabinet away from ignition sources.

Engineering Controls

Engineering controls are physical control measures that include mechanical devices or processes. They modify the source of the hazard or the transmission path to reduce exposure. They're "passive" controls, meaning they function without the worker needing to actively "do" something.

Examples: Fixed guards on a conveyor belt prevent access to nip points. Interlock guards cut power if a gate is opened. Local Exhaust Ventilation (LEV) captures welding fumes or silica dust at the point of generation. Governors installed on site vehicles physically prevent speeding. Edge protection (temporary handrails) on a roof prevents falls.

Level 3: Administrative Controls and PPE

These are the lowest levels of control and are considered the least effective. Regulation 36 dictates they should only be used if Level 1 and 2 controls are not reasonably practicable, or as an interim measure while higher controls are being implemented.

Administrative Controls

Administrative controls are systems of work or work methods that minimise exposure to a hazard. They rely entirely on human behavior, supervision, and compliance. If the worker forgets, is fatigued, or chooses to ignore the control, the safety measure fails immediately.

Examples: Safe Work Method Statements (SWMS), Standard Operating Procedures (SOPs), and Permits to Work. Competency assessments, inductions, and toolbox talks. Warning signs, floor markings, and exclusion tape. Job rotation to limit the time a worker is exposed to vibration or noise. Maintenance schedules to ensure equipment is checked regularly.

Personal Protective Equipment (PPE)

PPE is the "last line of defence." It places a barrier between the worker and the hazard but does nothing to reduce the hazard itself. It requires proper selection, fit, maintenance, and constant usage.

Examples: Respiratory Protective Equipment (RPE) like P2 masks. Hearing protection (earmuffs/plugs). Safety glasses, hard hats, gloves, and high-visibility clothing. Fall arrest harnesses (which do not prevent the fall, but mitigate the consequence).

Why Control Measures Matter

The rigorous implementation of control measures is not just an operational necessity—it's a legal imperative with significant consequences for non-compliance.

Legal Compliance

Under the WHS Act, you have a primary duty to ensure, so far as is reasonably practicable, the health and safety of workers. The courts have consistently interpreted this "assurance" as requiring the provision of safe systems of work and safe plant—which is achieved through control measures.

Failure to implement adequate controls is the primary evidence used by regulators to prove a breach of duty in prosecution cases. Penalties can reach millions of dollars for corporations and imprisonment for officers in cases of reckless conduct or industrial manslaughter.

Regulatory Requirements

Specific regulations mandate controls for all hazards:

Business Value

Beyond compliance, effective control measures drive business value. Automated handling (Elimination) is often faster and more consistent than manual handling. Preventing incidents avoids the direct costs of workers' compensation claims and the indirect costs of downtime, investigation, and reputational damage.

A workplace that visibly invests in high-level controls—like dust extraction systems or ergonomic tools—demonstrates care for worker wellbeing, improving retention and morale.

Common Challenges and Failure Modes

Implementing control measures is fraught with challenges. Safety controls erode over time due to production pressures and complacency—a phenomenon known as "drift into failure."

The "Paper Safety" Illusion

A common failure mode is the over-reliance on administrative controls that exist only on paper. You may have a comprehensive SWMS describing how to work safely at heights, but if you fail to provide the necessary physical equipment, the SWMS is legally and practically insufficient.

Administrative controls often seem cheaper, but the cost and effort to sustain a training programme or tedious procedure can easily exceed the cost of an engineering control.

Drift and Normalisation of Deviance

Controls, especially administrative ones, suffer from "drift." Over time, workers may find a shortcut that bypasses a safety procedure. If no accident occurs, this deviance becomes normalised. The control effectively ceases to exist, even though it remains in the manual.

This leads to a state where your organisation believes it is protected by controls that are no longer practised on the floor.

Maintenance Neglect

Engineering controls are only effective if maintained. A local exhaust ventilation system is a high-level control for silica dust. However, if the filter is clogged or the ducting is leaking, it provides zero protection. The worker, believing they are protected, may continue to work in a hazardous environment.

Regulation 37 specifically targets this failure mode, making the maintenance of the control as legally critical as the installation.

Risk Transfer

Implementing a control for one hazard can inadvertently introduce another. Enclosing a noisy machine (Isolation) to reduce noise exposure might cause the machine to overheat, introducing a fire hazard, or make it difficult to visually inspect, leading to mechanical failure risks.

This necessitates a secondary risk assessment of the control measure itself before implementation.

Inversion of the Hierarchy

Organisations often default to the bottom of the hierarchy (PPE and Training) because it appears cheaper and faster. Issuing earplugs is easier than re-engineering a production line.

This approach leaves the hazard active. If the PPE fails, is forgotten, or fits poorly, the worker is exposed to the full force of the hazard. This "inversion" is a primary target for regulators during inspections.

Best Practices for Implementing Control Measures

To ensure your control measures are effective and legally compliant, adopt the following best practices.

Defence in Depth (Layering Controls)

Rarely is a single control sufficient. Best practice involves layering controls from different levels of the hierarchy.

Example (Silica Dust): Use materials with lower silica content (Substitution). Use on-tool water suppression to kill dust at the source (Engineering). Implement exclusion zones and rotate workers to limit exposure time (Administrative). Require the use of P2 respirators as a final barrier (PPE).

Consultation is Critical

Consultation with workers is not just a legal requirement (Section 47 of the WHS Act)—it's a quality assurance mechanism for controls. Involve the workers who do the job in the selection of the control. They're best placed to identify why a proposed engineering control might be impractical or introduce new risks.

The Lifecycle Approach (Plan, Do, Check, Act)

Treat control measures as living systems, not one-off installations. Assess the risk and select the highest practicable control. Implement the control, including necessary training and resources. Verify the control is working—is the noise level actually lower? Is the dust count reduced? (Regulation 38 Review). Maintain, repair, or upgrade the control as technology improves.

Document the "Why"

When a higher-order control (like elimination or engineering) is not used, document why it was not reasonably practicable. Keep records of the decision-making process. If you choose administrative controls over engineering, you must be able to prove that the cost of engineering was grossly disproportionate or technically infeasible.

This documentation is your primary legal defence.

Critical Control Management

For high-consequence risks (fatalities or catastrophic events), identify "Critical Controls"—the few controls that must work to prevent the incident. Subject these critical controls to higher scrutiny, more frequent auditing, and stricter performance standards than general safety controls.

Applying Control Measures to Psychosocial Hazards

Recent amendments to WHS regulations across Australian jurisdictions have explicitly categorised psychosocial hazards (bullying, stress, fatigue, harassment) as risks that must be managed using control measures.

This shifts the focus from "resilience training" (Level 3 - Administrative) to "work design" (Level 1/2 - Elimination/Engineering), such as redesigning rosters to reduce fatigue or redefining roles to reduce role conflict.

For psychosocial hazards, "Good Work Design" functions as an engineering control. Increasing worker autonomy addresses low job control—a recognised hazard. Clearly defining organisational roles eliminates ambiguity-related stress.