Welding Fume Control — LEV, RPE and the HSE Crackdown (2026)

Why Welding Fume Suddenly Matters More

Welding fume is a complex mix of fine metal particles and gases produced when metal is heated to melting point. For years the focus was on stainless steel fume because of its hexavalent chromium and nickel content. The big shift came when international classification confirmed that mild steel welding fume — the everyday fume from welding ordinary carbon steel — can also cause cancer.

In practice the health effects include:

• Lung cancer — the reason mild steel fume is now treated as a carcinogen.
• Other lung damage — including links to kidney effects and an increased risk of respiratory infections such as pneumonia.
• Metal fume fever — a flu-like reaction (often from galvanised or zinc-coated steel) that leaves welders feeling rough for a day or two and is an early warning sign of overexposure.
• Asthma and occupational lung disease from repeated exposure over a working life.

Because the fume is now classed as a carcinogen, the legal expectation is that you reduce exposure as low as is reasonably practicable — not just below a number, but as far down as you can sensibly get it.

What the HSE Now Expects

Following the reclassification, the HSE issued a clear enforcement message: there must be effective control of fume for all welding activities, indoors and outdoors, and regardless of how long the job takes. The key points that trip people up are:

• General ventilation is no longer enough for indoor welding. Opening a roller door or relying on a fan to push fume around the workshop does not count as effective control. You need to capture the fume at source.
• Outdoor welding is not exempt. Even working outside, suitable respiratory protective equipment (RPE) is now expected, because the welder's breathing zone is still in the plume.
• Duration does not matter. "It was only a five-minute weld" is not a defence. The expectation applies to occasional welding just as much as to a full shift in a fabrication shop.

HSE inspectors do visit fabrication workshops and construction sites specifically looking at fume control, and they will issue improvement or prohibition notices where controls are inadequate. This is one of the areas where "we've always done it this way" is now a genuine liability.

The Legal Basis: COSHH 2002

The legal framework here is the Control of Substances Hazardous to Health Regulations 2002 (COSHH). Welding fume is a hazardous substance, so the standard COSHH duties apply. In plain terms, you must:

• Assess the risk — carry out a COSHH risk assessment that considers the type of metal, coatings, the welding process, the location and how long the work lasts.
• Control exposure — put controls in place so that exposure is prevented or, where that is not reasonably practicable, adequately controlled.
• Use the best practicable controls — because fume is a carcinogen, you have a specific duty to reduce exposure as low as is reasonably practicable using the most effective measures available, not just the cheapest.

COSHH also brings in duties to maintain controls, examine and test engineering controls, monitor exposure where needed, provide health surveillance where appropriate, and inform, instruct and train your welders. Each of those is covered below.

The Control Hierarchy for Welding Fume

COSHH expects you to work down a hierarchy of controls rather than jumping straight to a dust mask. For welding fume that hierarchy looks like this.

1. Eliminate or Reduce the Fume

The first question is always whether you can avoid creating the fume in the first place, or create less of it. Practical options include:

• Choosing a different joining method where one exists (mechanical fixing, bolting, adhesive).
• Using a lower-fume welding process or technique — process and parameter choices have a big effect on how much fume is generated.
• Selecting lower-fume or lower-toxicity consumables where the job allows.
• Automating or mechanising the weld so the operator is removed from the breathing zone.
• Removing coatings such as paint, oil or galvanising from the weld area first, where it is safe and practical to do so, to cut down on the worst fume.

2. Engineering Controls — LEV at Source

Where you cannot eliminate the fume, the primary engineering control is Local Exhaust Ventilation (LEV) — fume extraction that captures the fume at, or very close to, the arc before it reaches the welder's breathing zone. In welding this usually means on-torch extraction (an extraction nozzle built into or clipped onto the MIG torch) or a capture hood / extracted bench positioned right at the weld.

LEV only works if it is designed, positioned and used correctly. The capture point must be close to the arc and moved with the work — an extraction arm left a metre away while you weld at the other end of the bench is doing almost nothing. Suitable general ventilation sits alongside LEV to deal with any residual fume and keep the wider workshop air reasonable, but it never replaces capture at source.

3. RPE — Powered Air-Fed Helmets

Even good LEV does not always bring exposure down far enough on its own — and for all outdoor welding, RPE is expected as well. Respiratory Protective Equipment is the last line of the hierarchy, used on top of the controls above, not instead of them. For welding the most practical option is usually a powered air-fed welding helmet, which combines the visor and a powered respirator that feeds filtered air into the headtop.

Where a powered helmet is not used, the RPE must still provide an adequate level of protection — typically a P3 / FFP3 standard respirator suitable for the fume. RPE must be both adequate (offers enough protection for the exposure) and suitable (right for the wearer, the task and the environment).

LEV: Testing and Maintenance (the 14-Month Rule)

Buying an extraction unit is not the end of the job. Under COSHH, LEV must be properly maintained and given a Thorough Examination and Test (TExT) by a competent person at least every 14 months. The 14-month interval exists so the test naturally drifts across different times of year rather than always falling in the same month.

Alongside the formal TExT you should:

• Carry out regular visual checks and keep filters, hoses and capture hoods clean and undamaged.
• Make sure welders know how to position and use the extraction correctly — the best LEV in the world fails if the arm is parked out of reach.
• Keep records of examinations, tests and maintenance for inspection.

RPE: Face-Fit Testing and Beards

RPE only protects the wearer if it actually seals or supplies clean air properly. Any tight-fitting respirator — a half mask or FFP3 disposable — must be face-fit tested to the individual wearer, and facial hair along the seal line breaks the seal and invalidates the protection. This is the single most common failing the HSE finds with RPE.

This is exactly why powered air-fed, loose-fitting welding helmets are so popular for welders: because they are loose-fitting and supply their own air, they avoid the tight-seal face-fit and beard problem altogether, which suits welders who have beards or who can't reliably maintain a clean-shaven seal. For the full detail on choosing RPE and on the face-fit process, see our guides to RPE for trades and face-fit testing.

Other Measures That Matter

• Keep others away from the plume. The duty isn't only to the welder — labourers, fitters and anyone else nearby need protecting too. Screen the work and keep non-welders out of the fume.
• Don't put your head in the plume. A simple change in body and head position keeps your breathing zone out of the rising fume column and makes every other control work better.
• Health surveillance. Where exposure means it is required, provide health surveillance (for example respiratory questionnaires and lung function checks) so early effects are picked up.
• Training and information. Welders must be told the risks, shown how to use LEV and RPE correctly, and understand why it matters — this is a specific COSHH duty, not a nicety.
• Good housekeeping. Keep the work area clean, store consumables properly and don't let settled fume and dust build up where it can be disturbed.

Occasional Welding Counts Too

It is worth repeating, because so many trades get caught out: these duties apply to occasional welding on a construction site just as much as to a dedicated fabrication shop. If a groundworker tacks a bracket, a fitter welds a handrail, or a maintenance team makes a quick repair, the same control expectations apply — capture the fume at source where you can, and wear suitable RPE. The fact that welding isn't your main trade does not lower the bar.

Quick Reference: Welding Fume Controls

The Bottom Line

Welding fume is now treated as a carcinogen, and the HSE expects effective control for every weld — indoors or out, five minutes or five hours. Get a COSHH assessment done, fit LEV that captures fume at source and gets its 14-month TExT, back it up with a powered air-fed helmet, and make sure your welders are trained and (where tight-fitting RPE is used) face-fit tested. Do that and you protect your team's lungs and keep the inspector off your back.