Precision laser and thermal cutting generate ultra-fine metal oxide particles (often in the PM1–PM2.5 range). These penetrate deep into the lungs and can include oxidised iron, chromium, nickel, and manganese. Beyond immediate irritation, long-term risks include respiratory disease. COSHH requires exposure control, and HSE expects engineering measures rather than reliance on masks.

Capture at source

Start with the process. Keep the workpiece flat, minimise gaps in slats, and ensure downdraft tables are sealed to prevent bypass. Where operations are open or during set-up and inspection, position a WFE unit so the extraction arm crosses the fume plume at the cut line, keeping the hood close without obstructing the path. Check the enclosure integrity around the beam path and close access doors between tasks.

LEV performance depends on airflow under load. Inspect hoods for dents or misalignment, and verify duct integrity and damper positions. Use prefilters to protect final HEPA stages, and ensure final filtration is suitable; H14 is recommended where fine or carcinogenic particulate is present. Record checks and remedial actions.

Control in the air

Where residual fume escapes, create a consistent airflow pattern away from operators. Use air scrubbers or negative air machines to pull contaminated air across the room into H13/H14 filtration and vent cleaned air back or outside. Place units so they do not blow across the cut table or resuspend settled dust. Match duty to the room size based on required air changes and verify with smoke tests. Clean or change filters when pressure rise or airflow drop indicates loading.

Housekeeping that prevents re-exposure

Avoid sweeping and compressed air, which re-aerosolise fines. Use an industrial H-class vacuum with antistatic hoses for the table, rails, enclosure tracks, and nearby floors. Allow hot dross to cool fully before removal. Bag waste carefully, label it, and store it in lidded containers. Check vacuum seals, and schedule filter inspections to maintain consistent suction.

Monitor and confirm control

Set a baseline with air monitoring during typical production, then track trends. Place instruments at breathing height near operators and at room exhaust points. Use alarms to prompt checks when concentrations rise; this often signals a capture issue, worn seals, or filter loading. Keep concise COSHH records of readings, actions, and outcomes.

RPE, training, and behaviours

Provide FFP3 or P3-powered RPE for short tasks or as a secondary layer when engineering control cannot fully contain fume. Fit test, maintain, and store RPE correctly. Train operators to position hoods, close enclosures, and report airflow changes early.

• Keep the cut zone enclosed and hoods close to the source
• Verify airflow under load and maintain H14 final filtration where needed
• Use air monitoring to catch issues before exposure rises
• Vacuum only; never sweep or blow down
• Record checks and fixes under COSHH

With disciplined source capture, room control, and simple verification, fine metal oxide fumes can be managed without disrupting throughput and with clear evidence of control.