Welding Fume Control: HSE Requirements Explained
Welding Fume Control: HSE Requirements Explained
A practical guide for UK employers on controlling welding fume exposure, meeting HSE requirements, and selecting the right respiratory protection for your welders.
Contents
1. What Changed in 2019 — The HSE Enforcement Shift
In February 2019, the Health and Safety Executive (HSE) significantly strengthened its enforcement expectations for welding fume control. This wasn’t new legislation — but it was a major shift in how existing regulations would be enforced.
The Key Change
The International Agency for Research on Cancer (IARC) confirmed that all welding fume — including mild steel welding fume — can cause lung cancer. There is also evidence linking it to kidney cancer. As a result, the HSE’s Workplace Health Expert Committee endorsed the reclassification of mild steel welding fume as a human carcinogen.
What this means in practice:
General Ventilation is No Longer Enough
Before 2019, some employers relied on general workshop ventilation for mild steel welding. This is no longer acceptable. Suitable engineering controls are required for all indoor welding.
Duration Doesn’t Matter
Whether it’s 5 minutes or 8 hours, all welding activities require appropriate controls. There is no “safe” level of exposure to a carcinogen.
Outdoor Welding Needs Controls Too
You can’t rely on “fresh air” outdoors. Welders working outside must be provided with suitable respiratory protective equipment (RPE).
Others Nearby Are At Risk
It’s not just welders who need protection. Anyone in the vicinity of welding operations may be exposed and needs to be considered in your risk assessment.
2. Health Risks from Welding Fume
Welding fume is a complex mixture of metal particles, gases, and vapours produced when metals are heated above their melting point. The composition varies depending on the materials being welded, consumables used, and surface coatings present.
Confirmed health effects include:
Lung Cancer
IARC has confirmed that exposure to welding fume causes lung cancer. This applies to all types of welding fume, not just stainless steel.
Kidney Cancer
There is limited but growing evidence that welding fume exposure may also cause kidney cancer.
Occupational Asthma
Welding fume can cause occupational asthma, particularly from stainless steel welding which contains chromium and nickel — known asthmagens.
Metal Fume Fever
Exposure to fume from galvanised or zinc-coated metals causes flu-like symptoms. While usually temporary, repeated exposure is harmful.
Neurological Effects
Manganese in mild steel welding fume can cause neurological effects similar to Parkinson’s disease with prolonged exposure.
Pneumonia & COPD
Welders have increased susceptibility to pneumonia and chronic obstructive pulmonary disease (COPD). “Welder’s lung” is a recognised occupational condition.
Materials That Increase Risk
Some materials present additional hazards beyond standard mild steel. Stainless steel produces hexavalent chromium and nickel compounds. Galvanised steel releases zinc fume. Painted, primed, or coated surfaces can release additional toxic substances. Your risk assessment must account for all materials being welded.
3. Employer Duties Under COSHH
Welding fume is a substance hazardous to health and is regulated under the Control of Substances Hazardous to Health Regulations 2002 (COSHH), alongside the Health and Safety at Work Act 1974.
As an employer, you must:
1. Assess the Risk
Carry out a COSHH risk assessment for all welding activities. Consider the welding processes, materials, duration, location, and who might be exposed.
2. Implement Controls
Put in place suitable control measures following the hierarchy of controls. Engineering controls (LEV) should be the primary measure, supplemented by RPE where necessary.
3. Maintain Equipment
Ensure all control equipment — LEV systems, RPE — is properly maintained, examined, and tested. Keep records of maintenance and testing.
4. Train Workers
Provide information, instruction, and training on the risks and how to use control measures correctly. This includes proper use of LEV and RPE.
5. Health Surveillance
Where risk assessment identifies a need, provide health surveillance for exposed workers. This is particularly important for stainless steel welding (asthma risk).
6. Review Regularly
Review your risk assessment regularly, and whenever there are significant changes to processes, materials, or equipment.
4. The Control Hierarchy — LEV, RPE & More
COSHH requires employers to follow a hierarchy of control measures. You should always consider controls at the top of the hierarchy first, before relying on measures further down.
Hierarchy of Controls for Welding Fume
Eliminate
Can you avoid welding altogether? Consider cold joining techniques: mechanical fastening, adhesive bonding, press-fitting.
Substitute
Can you use a less hazardous process? Some processes generate less fume than others. Can you avoid welding coated or treated materials?
Engineering Controls (LEV)
Local Exhaust Ventilation captures fume at source before it reaches the welder’s breathing zone. This is the primary control for indoor welding.
Respiratory Protective Equipment (RPE)
Where LEV alone cannot adequately control exposure, or for outdoor welding where LEV isn’t practical, suitable RPE must be provided.
Health Surveillance
Monitor workers’ health to detect early signs of disease. Required where significant risk remains despite controls.
Important: RPE is Not a Substitute for LEV
RPE should supplement engineering controls, not replace them. Where it’s reasonably practicable to provide LEV, you should do so — even if you also provide RPE. The exception is outdoor welding, where LEV is generally not practical and RPE becomes the primary control.
5. Local Exhaust Ventilation (LEV) Options
LEV systems capture welding fume at or near the source, removing it from the breathing zone before it can be inhaled. The right LEV solution depends on your workpieces, welding processes, and workshop layout.
On-Torch Extraction
Extraction built into the welding gun itself. Highly effective for MIG welding when correctly set up. Captures fume immediately at the arc. Modern high-efficiency welding guns can provide excellent control.
Extracted Benches/Booths
Downdraught benches or rear-extraction booths. Ideal for small to medium workpieces that can be brought to the bench. Doesn’t require repositioning during welding.
Movable Extraction Arms
Flexible arm with capture hood. Suitable for larger workpieces or variable work locations. Requires correct positioning by the welder and repositioning as work progresses.
Extracted Welding Booths
Enclosed booths with rear extraction for larger fabrications. Workpiece mounted on turntable to keep fume drawn toward extraction. Good for repetitive production work.
LEV Maintenance Requirements
Under COSHH, LEV systems must be:
- Properly designed and commissioned for the specific welding processes
- Subject to thorough examination and test (TExT) at least every 14 months
- Visually checked regularly by users to ensure it’s working
- Maintained in efficient working order
- Records of examinations and tests kept for at least 5 years
6. RPE Selection: APF, TH Ratings & When to Use PAPR
When LEV alone cannot adequately control exposure, or for outdoor welding, you must provide suitable Respiratory Protective Equipment (RPE). Selecting the right RPE depends on the level of protection needed and the nature of the work.
Understanding Protection Factors
| RPE Type | TH Class | APF (UK) | Inward Leakage | Face-Fit Test Required? |
|---|---|---|---|---|
| FFP3 Disposable Mask | — | 20 | — | Yes |
| Half Mask + P3 Filter | — | 20 | — | Yes |
| Full Face Mask + P3 Filter | — | 40 | — | Yes |
| Powered Air (TH2) | TH2 | 20 | <2% | No |
| Powered Air (TH3) | TH3 | 40 | <0.2% | No |
APF (Assigned Protection Factor) indicates how much the RPE reduces exposure. APF 20 means the concentration inside the mask is 20 times lower than outside. TH (Turbo Hood) classifications relate to powered air respirators with loose-fitting headtops.
HSE Minimum Requirements for Welding
- Where RPE is required, minimum APF 20 for general welding
- For confined or restricted spaces, APF 40 is required
- Powered respirators recommended when welding for more than 1 hour per day
- Tight-fitting RPE requires face-fit testing for each wearer
- Wearer must be clean-shaven where tight-fitting RPE seals to the face
Why TH3 PAPR is the Best Option for Professional Welders
Higher Protection (APF 40)
TH3 systems provide APF 40 — double the protection of FFP3 disposables or TH2 powered air. With a Nominal Protection Factor up to 500, they offer the highest air-purifying protection available.
No Face-Fit Testing
Loose-fitting PAPR helmets don’t require face-fit testing. This simplifies deployment and eliminates issues with facial hair or varying face shapes.
Comfortable for Long Shifts
Continuous filtered airflow keeps welders cool and comfortable. Tight-fitting masks cause fatigue and get loosened or removed — defeating the purpose.
Combined Eye, Face & Respiratory Protection
Welding PAPR helmets integrate auto-darkening filters with respiratory protection. The helmet stays in place throughout — no removing RPE to check welds.
7. Compliance Checklist
Welding Fume Control — Employer Checklist
- Risk Assessment: Have you carried out a COSHH risk assessment for all welding activities, considering processes, materials, duration, and location?
- LEV in Place: For indoor welding, have you installed suitable local exhaust ventilation (on-torch, benches, booths, or extraction arms)?
- LEV Maintained: Is your LEV subject to regular visual checks, maintenance, and thorough examination & test (TExT) at least every 14 months?
- RPE Provided: Where LEV alone isn’t adequate, or for outdoor welding, have you provided suitable RPE with at least APF 20?
- Face-Fit Testing: For tight-fitting RPE, have all wearers been face-fit tested? Are they clean-shaven where the mask seals?
- RPE Programme: Do you have an RPE programme covering selection, training, maintenance, storage, and supervision?
- Training: Have workers been trained on the risks of welding fume and how to correctly use LEV and RPE?
- Health Surveillance: Where risk assessment identifies a need (e.g., stainless steel welding), have you arranged health surveillance?
- Records: Are you keeping records of risk assessments, LEV testing, RPE maintenance, training, and health surveillance?
- Others Protected: Have you considered and protected other workers who may be exposed to welding fume in the vicinity?
Need Welding Respiratory Protection?
We supply TH3 powered air welding respirators to fabricators, aerospace manufacturers, and oil & gas contractors across the UK. Competitive pricing, UK stock, VAT invoices provided.
View 3M Speedglas G5-01VC with Adflo Browse All Welding PAPRs8. Frequently Asked Questions
Do I need LEV for occasional welding?
HSE guidance indicates that engineered fume controls (LEV) will not normally be expected for occasional welding carried out less than once per week and lasting less than 1 hour. However, you must still provide suitable RPE and good general ventilation, and consider protection of others nearby. If welding is more frequent or longer duration, LEV is expected.
What RPE should I provide for outdoor welding?
LEV is not practical for outdoor welding, so RPE becomes the primary control. HSE recommends a powered air respirator or supplied air respirator with an APF of at least 20 as the best option for arc welders. A TH3 PAPR welding helmet (APF 40) provides excellent protection and comfort for outdoor work.
Do powered air welding helmets require face-fit testing?
No. Loose-fitting powered air respirators (like the 3M Speedglas with Adflo) don’t require face-fit testing because they don’t rely on a tight seal to the face. This is a significant practical advantage over tight-fitting alternatives.
What’s the difference between TH2 and TH3?
TH (Turbo Hood) ratings indicate the protection level of powered air respirators. TH2 provides APF 20 (less than 2% inward leakage). TH3 provides APF 40 (less than 0.2% inward leakage). TH3 offers double the protection factor and is recommended for heavier welding exposure.
Do I need health surveillance for welders?
Health surveillance is required where your risk assessment identifies a significant risk to health despite controls. It’s particularly important for stainless steel welding due to the asthma risk from hexavalent chromium and nickel. Health surveillance for occupational asthma should be carried out by a competent occupational health provider.
What about MIG welding — is that safer than other processes?
All welding processes produce hazardous fume. MIG welding can be effectively controlled with on-torch extraction when correctly set up. However, the fume is still carcinogenic and requires adequate controls regardless of the process.
How often does LEV need to be tested?
Under COSHH, LEV systems require thorough examination and test (TExT) at least every 14 months. Records must be kept for at least 5 years. In addition, users should visually check that LEV is working before use.
Sources & Further Reading
This guide was last updated in January 2026. While we strive to keep information accurate and current, always refer to the latest HSE guidance for definitive compliance requirements.
