The water pressure drops halfway through a cut. An extraction hose becomes blocked. A vacuum loses suction or a nozzle is damaged. The equipment still operates and the job is already behind schedule.
What happens next is a test of your silica dust control workplace system.
When a primary dust control is unavailable or no longer effective, affected work should not continue while workers and supervisors invent a temporary solution. For high-risk crystalline silica processing, NSW regulations require work that is not being completed in accordance with the silica risk control plan to stop immediately, or as soon as it is safe to do so. It can resume only in accordance with that plan.
That decision needs to be made before the water supply, extraction system or other critical control fails.
What the NSW Prosecution Shows About Control Failure
In July 2026, SafeWork NSW announced that a NSW stone-processing business and its sole director had been convicted and fined following guilty pleas in the Industrial Court of NSW. The proceedings arose from a March 2023 incident involving a risk of workers being exposed to respirable crystalline silica.
The business pleaded guilty to failing to comply with its primary health and safety duty. The director pleaded guilty to failing to comply with the duty of an officer. SafeWork NSW noted that both parties retained the right to appeal their sentences at the time of its release.
The parties are not named here because the more useful lesson is not who was prosecuted. It is what the matter should prompt other businesses to examine.
A silica system cannot be judged only by what happens when the machinery is operating normally. It also needs to manage predictable problems such as:
- Water pressure falling below an effective level
- A blocked or incorrectly positioned nozzle
- A damaged hose or connection
- Extraction losing suction
- A filter becoming full or blocked
- A shroud, guard or seal being damaged
- Replacement equipment or parts being unavailable
- Pressure from production schedules encouraging work to continue
The presence of a water feed, extraction unit or respirator does not by itself prove that workers are protected. The controls must be available, effective and used throughout the work.
The prosecution related to an incident in 2023. Since then, the regulatory environment has changed, including the engineered-stone ban and the introduction of more detailed requirements for crystalline silica processing in the NSW Work Health and Safety Regulation 2025. The manufacture, supply, processing and installation of covered engineered-stone benchtops, panels and slabs have been prohibited since July 2024, subject to limited arrangements for legacy products and exemptions.
The control principles remain relevant to concrete, brick, masonry, natural stone, tunnelling materials, demolition waste and other crystalline silica substances.
What Should Happen When a Primary Silica Control Fails?
The immediate response should be simple enough for a worker to follow while the job is under pressure.
1. Stop the affected processing
Stop the cutting, drilling, grinding, polishing, crushing or other affected processing immediately, or as soon as it is safe.
The NSW Regulation defines controlled processing as work using measures that eliminate or minimise risk so far as reasonably practicable, together with at least one specified control such as effective wet dust suppression, on-tool extraction, local exhaust ventilation, isolation or a filtered operator cabin. RPE must also be provided and worn where a person remains at risk after those controls are used.
If the measure your process relies on is no longer effective, continuing as normal may mean the processing is no longer controlled.
2. Make the equipment safe
Turn off, isolate or tag the affected equipment so that another worker cannot restart it without understanding the problem.
This may involve isolating:
- The cutting or processing equipment
- The water supply
- The extraction unit
- Electrical or pneumatic energy sources
- Any automatic restart function
The isolation method should suit the equipment and the nature of the fault. The important point is that a damaged control should not remain available for casual reuse.
3. Notify the authorised person
Workers should know exactly who must be contacted. Depending on your structure, this may be a supervisor, project manager, operations manager, maintenance coordinator or nominated WHS representative.
That person should have authority to:
- Keep the work stopped
- Arrange inspection and repair
- Restrict access to the area
- Approve a documented alternative
- Arrange specialist advice where necessary
- Authorise restart after verification
A procedure that says “report the problem” without identifying who decides what happens next leaves an operational gap.
4. Assess whether dust has escaped
A failed control may affect more than the person operating the tool.
Check whether dust or contaminated mist has spread to nearby workstations, walkways, vehicles, storage areas, lunchrooms or clean zones. Access may need to be restricted until the area has been contained and cleaned using an appropriate method.
Do not send another worker into the area with a broom or general-purpose vacuum.
5. Use only an approved alternative
An alternative method should be used only where it has been assessed in advance and shown to keep the processing controlled.
For example, an approved alternative may involve:
- Moving the task to another machine with verified water suppression
- Using a correctly matched on-tool extraction system
- Using a different process that generates less dust
- Moving the work to a controlled enclosure
- Rescheduling the task until the primary system is repaired
A spray bottle, sponge or garden hose is not an equivalent replacement for purpose-designed suppression. The NSW silica Code of Practice states that effective water suppression must provide the right amount of water or fine mist for the full duration of the work. It also identifies handheld spray bottles, sponges and garden hoses as inadequate for suppressing respirable crystalline silica.
6. Verify the control before restarting
Repairing the obvious fault is not necessarily enough.
Before restarting, confirm that:
- Water flow and pressure are adequate
- Nozzles are correctly positioned
- Hoses and connections are free from leaks or damage
- Extraction has sufficient airflow
- Filters, shrouds, flaps and guards are in place
- The work area has been cleaned
- Workers understand the controls being used
- Required RPE is available and correctly fitted
- The defect and repair have been recorded
- The risk control plan or SWMS remains suitable
For high-risk processing, NSW law requires the silica risk control plan to document the controls and explain how they will be implemented, monitored and reviewed. If work departs from that plan, it must stop and resume only in accordance with it.
Can Work Continue Using RPE Alone?
RPE should not become the automatic fallback whenever water suppression or extraction fails.
The NSW Regulation allows RPE-only controlled processing where the specified isolation or engineering measures are not reasonably practicable. That is not the same as deciding, after equipment breaks down, that wearing a mask is more convenient than stopping the job.
Before relying on RPE alone, the business would need to determine that the higher-order measures are not reasonably practicable and ensure the selected RPE is suitable for the worker, task, contaminant level and working environment.
For high-risk processing, the work must also remain consistent with the applicable silica risk control plan or qualifying SWMS.
RPE is an important control, but it relies on correct selection, fit, use, maintenance and supervision. It does not contain dust at its source or protect unprotected people standing nearby.
What a Silica Risk Control Plan Should Cover
A silica risk control plan should describe more than normal production.
It should tell workers and supervisors what happens when normal controls are unavailable, damaged or ineffective.
Your breakdown arrangements should cover:
- Clear stop-work triggers
- How equipment will be isolated
- Who must be notified
- Who can authorise an alternative
- Which alternatives have already been assessed
- How access to contaminated areas will be controlled
- How dust and slurry will be cleaned
- What inspections or tests are required
- Who can approve restart
- What records must be completed
- When the risk assessment and plan must be reviewed
For construction work that is also high-risk construction work, a SWMS may be used instead of a separate silica risk control plan where it meets the required content. The document must identify the high-risk processing, include the risk assessment and explain how controls will be implemented, monitored and reviewed.
Write specific stop-work triggers
“Stop if the control fails” is open to interpretation.
More useful triggers include:
- No visible water reaching the cutting point
- Water flow becoming intermittent
- Water pressure falling below the equipment requirement
- Dust becoming visible outside the capture point
- Extraction alarms activating
- A noticeable reduction in suction
- A split, disconnected or blocked hose
- A damaged shroud, guard or seal
- A filter-change indicator activating
- A worker being unable to wear the required RPE correctly
These triggers give workers a practical basis for acting before exposure becomes routine.
Maintenance Should Find Problems Before the Shift Does
Dust-control equipment needs the same maintenance discipline as production equipment.
The NSW silica Code explains that silica-containing dust is abrasive and can damage or wear tools and engineering controls. It recommends maintenance and cleaning schedules and regular inspections for wear, corrosion, damaged parts, air leaks, damaged guards and kinks, holes or leaks in water-suppression and extraction equipment.
A practical inspection should look beyond whether the equipment switches on.
For water suppression, check:
- Water supply and pressure
- Consistent flow at the point of dust generation
- Nozzle condition and alignment
- Hose condition
- Connections and valves
- Guards and spray containment
- Drainage and slurry management
For extraction, check:
- Suction at the tool
- Hose condition and connections
- Shroud position
- Filter condition
- Dust-container capacity
- Warning lights or alarms
- Damage that may reduce capture efficiency
Defects should be recorded, assigned and closed. Recurring faults should be escalated rather than repeatedly repaired without investigating why they continue.
RPE Must Fit the Worker and the Task
Where RPE is required, handing out the same disposable respirator to everyone is not a respiratory protection program.
Suitable RPE needs to be selected using information about the task, exposure, worker and work environment. The NSW Regulation specifies compliance with AS/NZS 1716:2012 and AS/NZS 1715:2009 for RPE used to control crystalline silica processing.
For tight-fitting RPE:
- The worker must pass a fit test before first use
- Fit testing should be repeated at least annually
- A new test is required when a different make or model is issued
- Retesting is needed after facial changes that may affect the seal
- The worker should conduct a fit check every time the respirator is put on
- Facial hair must not interfere with the sealing surface
- Training, cleaning, storage and maintenance records must be kept
SafeWork NSW advises that close-fitting RPE must not be issued where facial hair prevents an effective seal. Where a worker cannot use tight-fitting RPE for a valid reason, appropriately selected loose-fitting powered RPE may need to be considered.
RPE must also remain usable during the actual task. Heat, hard physical work, communication needs, safety glasses and other PPE can all affect whether the respirator remains effective.
Housekeeping Is Part of Silica Control
A cutting task may finish, but the risk does not end if dust or slurry is left behind.
Settled dust can be disturbed and become airborne again. Slurry can also become a dust source once it dries.
Safe housekeeping methods include:
- Low-pressure water cleaning
- Wet sweeping
- M- or H-class rated vacuum equipment
- Keeping slurry wet and contained
- Cleaning RPE and equipment in designated areas
- Sealing contaminated items where immediate cleaning is not possible
Compressed air, dry sweeping and general-purpose vacuum cleaners should not be used to clean silica-contaminated surfaces or clothing.
The breakdown plan should address cleanup before restart, particularly where the failed control may have released dust beyond the normal work area.
Use Air Monitoring to Verify Controls
Air monitoring helps determine what workers may be breathing during real work. It should verify the performance of the control system rather than be used to defend an obviously dusty process.
For high-risk crystalline silica processing, the NSW Regulation requires air monitoring in accordance with section 50. It also requires results exceeding the workplace exposure standard to be provided to the regulator as soon as reasonably practicable and no more than 14 days after the result is reported to the business.
The workplace exposure standard for respirable crystalline silica is 0.05 mg/m³ averaged over eight hours, adjusted where necessary for extended shifts. SafeWork NSW says monitoring should be completed by a suitably qualified person in the worker’s breathing zone under representative working conditions. Results must be provided to workers and air-monitoring reports retained for 30 years.
Consider reviewing or repeating monitoring after:
- A control failure
- A change in material
- New equipment or tooling
- A change in water flow or extraction
- A process or production-rate change
- Visible dust or contaminated mist
- A change in work location
- An exposure-standard exceedance
- Evidence that workers are not following the documented method
Monitoring should be representative of the work actually performed, including predictable variations and higher-exposure tasks.
Health Monitoring and the Silica Worker Register
Air monitoring and health monitoring perform different roles.
Air monitoring measures airborne contamination and helps assess exposure.
Health monitoring checks for changes in a worker’s health that may be associated with exposure.
For workers carrying out high-risk crystalline silica processing, the NSW Regulation requires health monitoring in accordance with the hazardous-chemical health-monitoring provisions. SafeWork NSW also requires relevant workers to be added to the Silica Worker Register within 28 days of commencing high-risk processing.
A worker using RPE may still require health monitoring. RPE does not remove the underlying health-monitoring obligation where the relevant risk or high-risk processing requirements apply.
The business should be able to confirm:
- Which workers carry out high-risk processing
- Whether they are registered
- When health monitoring commenced
- Who is supervising the monitoring
- Whether reports have been received and acted upon
- Whether adverse findings have triggered notification and review
- Whether monitoring records remain current and accessible
What Officers and Supervisors Should Verify
The prosecution involved both a business and its sole director. That reinforces a practical point: silica control is not only a workshop or site issue.
Officers must exercise due diligence to ensure the business complies with its WHS duties. SafeWork NSW describes this as keeping WHS knowledge current, understanding operational risk, ensuring resources and processes exist and are used, responding to hazard information and verifying those arrangements.
An officer should not rely only on a report saying “wet cutting is used”.
Useful verification questions include:
- What happens when the water or extraction system fails?
- Do workers know the stop-work trigger?
- Can production continue without supervisor approval?
- Which alternative controls have been assessed?
- Who verifies that extraction flow and water pressure are adequate?
- How quickly are critical defects repaired?
- Are repeat faults visible to senior management?
- Do air-monitoring samples reflect the real work?
- Are fit-test, health-monitoring and Worker Register records current?
- Who checks that corrective actions are properly closed?
Supervisors provide the day-to-day verification. They should observe the work, confirm controls are operating, prevent unauthorised alternatives, check RPE use, escalate defects and approve restart only within their level of authority.
Useful evidence includes pre-start checks, maintenance records, defect logs, photos, air-monitoring reports, fit-test certificates, training records and documented restart approvals.
Fail-Safe Silica-Control Checklist
| Stage | Checks |
| Normal operation | Current risk assessment completed; high-risk processing identified; silica risk control plan or qualifying SWMS available; water suppression or extraction checked; suitable RPE issued and fit tested; workers trained; cleaning equipment available. |
| Control breakdown | Processing stopped; equipment isolated; supervisor notified; access restricted where required; defect recorded; possible dust spread assessed; unauthorised workaround prevented. |
| Approved alternative | Alternative already assessed; included in the plan or SWMS; keeps the processing controlled; suitable equipment available; RPE requirements confirmed; workers instructed; approval recorded. |
| Safe restart | Repair completed; water flow or extraction performance verified; damaged components replaced; area cleaned; workers briefed; documents reviewed where required; monitoring or follow-up actions assigned; restart authorised. |
The checklist should be adapted to the material, equipment and work being performed. It does not replace a task-specific risk assessment, silica risk control plan or SWMS.
Plan for the Breakdown Before It Happens
A silica-control system is not fully tested while everything is operating normally.
It is tested when water pressure disappears, a filter blocks, a hose splits or a production deadline makes stopping inconvenient.
Workers should not have to decide on the spot whether a temporary hose, different vacuum or respirator is “probably enough”. The stop, escalation, alternative-control and safe-restart decisions should already be documented, understood and supported by the people supervising the work.
Review what your workers and supervisors are required to do when the main dust control becomes unavailable or ineffective. The decision to stop, escalate or use an approved alternative should be clear before equipment fails.
The Safety Dept. helps businesses keep critical WHS controls, responsibilities and supporting records current, so the documented system continues to reflect what happens in practice.