Welding Fume Control Occasional Welding BOHS Tool

“It’s Only Occasional Welding”… Until It Isn’t

Making Defensible Decisions on Welding Fume Control Using the BOHS Selector Tool

For many businesses, welding is not a core activity.
It happens occasionally — maintenance, repairs, minor fabrication — and because of that, welding fume control is often treated as a secondary issue.

That is exactly where risk creeps in.

From an enforcement perspective, occasional does not mean low risk, and it does not reduce an employer’s duty to control exposure to welding fumes, which are now clearly recognised as a serious health hazard.

Recently, we undertook a focused review of welding activities in a setting where welding was carried out intermittently rather than continuously. The aim was simple: to check whether the control measures in place were proportionate, suitable, and defensible.

Why Occasional Welding Needs Closer Scrutiny

In many workplaces, occasional welding presents greater challenges than routine welding because:

Health effects linked to welding fumes — including chronic lung disease and lung cancer — are cumulative. Exposure risk exists regardless of how frequently welding takes place.

From an HSE perspective, the question is not how often welding occurs, but how exposure has been assessed and controlled.

Using the BOHS Welding Fume Control Selector Tool

As part of this review, we used the Welding Fume Control Selector Tool developed by the British Occupational Hygiene Society (BOHS), in collaboration with industry specialists, academics, consultancies, and the Health and Safety Executive (HSE).

The tool is designed to support managers and supervisors by:

It is explicit that the tool does not replace a full risk assessment. Instead, it supports informed decision-making and helps ensure that control measures are selected logically and proportionately.

Engineering Controls First: The Role of LEV

One of the key outcomes of this exercise was reaffirming the central role of local exhaust ventilation (LEV) as the primary control measure for welding fumes wherever it is reasonably practicable.

LEV works by capturing welding fume at source, preventing it from dispersing into the wider workplace. When properly selected, positioned, maintained, and used, it:

From a compliance standpoint, LEV represents an engineering control, which sits higher in the hierarchy of control than personal protective equipment.

Poorly positioned or inadequately maintained LEV, however, offers little real protection and may give a false sense of control. This is why the BOHS tool is supported by Control and Management Sheets, which reinforce the importance of correct use, training, inspection, and maintenance.

RPE and Air-Fed Masks: Protecting the Individual

Where LEV alone cannot adequately control exposure — for example in confined spaces, poorly ventilated areas, during outdoor welding, or during higher fume-generating processes — respiratory protective equipment (RPE) becomes necessary.

This is where a critical distinction must be understood:

RPE, including air-fed welding masks, can be highly effective, but only when:

RPE should therefore be viewed as a supplementary control, addressing residual risk rather than compensating for the absence of effective engineering controls.

Tight-Fitting RPE Must Fit the Individual Wearer

Where a welder uses tight-fitting RPE — such as an FFP2 or FFP3 disposable respirator, or a reusable half-mask respirator — simply issuing the correct specification of mask is not enough.

Tight-fitting respirators rely on creating an effective seal against the wearer’s face. Because face shapes and sizes differ, a particular make, model or size of respirator may fit one employee but not another.

For this reason, tight-fitting RPE should be face fit tested to the individual wearer. The wearer also needs to be clean shaven wherever the respirator sealing surface contacts the face.

A successful face fit test relates to the specific make, model, type and size of respirator tested. If the employee later changes to a different facepiece, further face fit testing may be required.

For further information on face fit testing, see HSE INDG479 – Guidance on RPE Fit Testing.

Understanding Air-Fed Mask Options

During the review, particular attention was given to air-fed welding masks, which broadly fall into two categories:

Compressed Air-Fed Systems

Powered Air-Purifying Respirators (PAPR)

Both systems can form part of a compliant control strategy where justified by risk, but neither should be treated as a standalone solution in place of suitable ventilation.

Making Decisions That Stand Up to Scrutiny

From an HSE inspection or incident investigation perspective, the key question is rarely what equipment was available, but:

Using structured tools such as the BOHS Welding Fume Control Selector — alongside a task-specific risk assessment — helps demonstrate that:

Final Thoughts

Occasional welding is often where gaps in control go unnoticed, not through negligence, but through assumption.

Taking the time to review welding fume controls — particularly where activities are infrequent or changeable — helps ensure that arrangements remain effective, compliant, and appropriate.

In many cases, the most important control measure is not additional equipment, but clarity:

• clarity on risk
• clarity on responsibility
• clarity on why specific controls are in place

That clarity is what ultimately protects workers — and the business — when it matters most.