welding fume extraction not working what to do

Direct answer. If welding-fume local exhaust ventilation (LEV) is faulty or is not capturing fume effectively, pause the welding task and assess exposure before continuing. Tell the supervisor and affected workers, prevent use of the failed control, arrange competent repair, and verify that extraction is effective under the actual welding conditions before normal work resumes. If a different method is proposed meanwhile, a competent COSHH reassessment must show it adequately controls exposure; simply opening doors or handing out any mask does not automatically make the work safe. HSE says all welding fume can cause lung cancer, indoor work generally needs suitable engineering control such as LEV, and faulty controls should be repaired promptly. HSE welding fume guidance; HSE maintaining controls.

This Great Britain page addresses the live failure response at a welding operation. P4-136, an unpublished guide, covers LEV examination records; the existing COSHH compliance software page owns the commercial query. Do not create a second generic “what is LEV?” page or assume that a current test certificate guarantees effective capture at every workstation today.

Recognise a control failure

The issue may be an alarm, low airflow, damaged flexible arm, disconnected duct, clogged filter, incorrectly positioned hood, failed fan, changed weld position, draught or visible fume escaping the capture zone. A welder may notice a new smell or irritation, but absence of smell is not proof of control, especially for processes with little visible fume. HSE says the actual capture of fume matters, not just an airflow number; on-torch extraction needs a different performance check from a movable hood. HSE LEV and RPE maintenance.

Inspect under the real work configuration. A hood can pass a measurement when placed optimally yet miss fume while a large workpiece is repositioned. A flexible arm might be moved away for access. A replacement fan or duct alteration may change capture at other stations. Ask welders what they see during production; they often know which jobs are no longer controlled. Avoid looking directly at the welding arc without appropriate eye protection.

Example. The LEV test report is within its date, but a booth is moved and the extractor arm can no longer reach a long seam. Visible fume rises past the welder's breathing zone. The report does not settle the current exposure question. Stop or change the task, arrange competent assessment and reposition or redesign the extraction so it works where the weld is made.

Stop the affected exposure, not necessarily every activity

Identify which station, process and adjacent workers are affected. If only one extraction arm has failed, isolate that welding operation; other operations may continue if their own controls remain effective. If the shared fan or duct system is down, more stations may be affected. Label the unavailable control and tell shift leaders so a later worker does not resume the job. Consider workers nearby who may receive drifting fume even if they are not welding.

HSE's hierarchy starts with avoiding or reducing fume generation where possible, then capturing it at source and using suitable RPE where LEV alone cannot adequately control exposure or cannot reasonably be provided. A temporary alternative might be a different workstation with working extraction, a cold joining method or postponement. It should not be an improvised replacement chosen only to maintain output. HSE control welding-fume exposure.

If suitable RPE is needed as part of an assessed interim method, ensure the selected device protects against the actual contaminants and fits the worker and duration of work. Particulate filters do not protect against all gases in welding fume. HSE's advice differentiates short and long tasks and stresses face fit for tight-fitting masks. This article does not prescribe a universal respirator; a competent COSHH assessment should determine whether the alternative is adequate. HSE welding controls.

Investigate the cause

Review the LEV user manual, commissioning information, latest examination report, routine checks, filter maintenance, performance indicators and any recent process change. Was the hood moved, duct damaged, damper closed, fan slowed, filter clogged, flexible arm leaking or another workstation added? Is the welding material or process different from what the system was designed for? A complete repair addresses the cause and any knock-on effect across the system.

Use a competent ventilation engineer where performance is unclear. HSE warns that makeshift airflow “tell-tales” are generally not adequate evidence of LEV performance. A thorough examination and test is a systematic check of whether the system contributes to adequate exposure control. The routine check for today's job and the periodic formal examination are related but different activities. HSE LEV FAQs.

HSE states that welding LEV must be thoroughly examined and tested at least every 14 months for the ordinary case, with records retained for at least five years. More frequent checks may be needed through risk assessment or special processes. A test date does not authorize a welder to ignore a current failure. HSE maintaining welding controls.

Verify repaired control under actual use

After repair, a competent person should check that the LEV captures fume effectively for the task, not simply that the fan runs. Compare relevant measurements with the original commissioning or test baseline, check the hood position and observe the real weld under suitable eye protection. For processes with little visible fume, a competent test method may be needed. Record the scope, results and any limitations. If the repair was substantial, ask whether a new commissioning or thorough-examination test is required. HSE LEV FAQs; HSE LEV commissioning.

The restart decision should include the adjacent workers and the actual production configuration. A successful test at one weld point may not cover a large, frequently repositioned component. Confirm the welder can use the extraction without defeating guards or adopting an awkward posture. Brief operators on the failure signs and what to do if it recurs. Close the incident or corrective action only when control is demonstrably restored or a separately assessed alternative is in place.

If workers may have been exposed while the control failed, assess the period, task and affected people with occupational-health advice where appropriate. Record the facts without diagnosing an individual or promising that a single air sample can retrospectively quantify every exposure. Review whether routine checks could have detected the failure sooner.

Make the record useful for the next shift

The record should identify the station and LEV asset, time of failure, symptom, affected welding work, interim restriction, who was notified, repair action, competent performance check, restart authority and follow-up monitoring. Link it to the formal LEV report and maintenance history. If a shared system affected several workstations, record them all. Do not close a system-wide failure against one hood and leave other operators unaware.

Look for patterns. Repeated blocked filters may point to inadequate maintenance frequency. A recurring capture problem on one product may mean the hood was never suitable for that task. HSE says failure patterns in records can guide preventive maintenance. The corrective action may be redesign rather than one more repair. HSE maintain exposure controls.

Common mistakes

• Continuing to weld because the LEV's 14-month examination date is current.
• Measuring airflow alone while fume visibly escapes the capture zone.
• Treating a fan restart or filter change as proof of adequate control.
• Assuming general ventilation replaces effective source capture for indoor welding.
• Issuing an unsuitable mask without a COSHH reassessment, fit and training.
• Repairing one hood while ignoring the shared fan or neighbouring stations.
• Closing a work order before observing the control in the real welding configuration.

Where Complys fits

The COSHH compliance software page is the commercial owner for reviewing how assessment, control and corrective-action records can be organised. This guide does not claim Complys measures airflow, detects failed capture, selects RPE, performs LEV testing or certifies exposure control. For one welding station, ask the operator to show how a failed extraction check is reported, who stops the task and what evidence allows work to resume.

Primary sources checked 4 October 2026

• HSE welding fume: protect your workers.
• HSE maintain exposure controls and LEV/RPE maintenance.
• HSE control welding exposure and LEV FAQs.

Publication gate: A competent COSHH/ventilation reviewer should validate any site-specific interim RPE or LEV performance method. Repeat current HSE interval and record-retention checks when publishing.

General information, not legal advice. Verify current requirements against the primary sources linked above.