Monitoring Exposure to Welding Fume

When is air monitoring needed?

Air monitoring and measurement may be needed where there is a serious risk to health from the inhalation of welding fume and the likely exposure level of the welders to the fume is not known, e.g. during the manual metal arc (MMA) welding of stainless steel.

Monitoring may also be needed to help confirm that the control measures in use are working correctly, as a deterioration or failure of engineering controls could result in welders being exposed to high levels of fume.

Under the Control of Substances Hazardous to Health (COSHH) system, an initial exploratory exposure monitoring exercise may be needed to reach an accurate judgement about the risk to health. The results will then influence the assessment of how well control measures for the welding fume are working. The investigation will also need to look at other factors that can influence exposure on the day, such as the production rate setting the amount of welding work needed. These things will influence the personal results of the survey for exposure to welding fume.

When is air monitoring needed?

welding coated material, eg galvanised steel
using metals which have low exposure limits, such as nickel and chromium
fume is seen in the air coming away from the welding process
fume is seen which isn’t being captured by the existing extraction
there are concerns about the performance of the existing control measures
you want to gather information which will help specify further control measures.

Why do I need air monitoring?

The monitoring information can be used to:

help to inform the COSHH assessment for the task as it gives an illustration of the exposure risk
help to select the right fume control solutions
check that exposure limits are not exceeded
check that controls work well enough, or if improvements are needed
check that new controls work well enough
help choose the right level of respiratory protection
influence the health surveillance programme.

Legal Requirements

The COSHH Regulations require employers to:

Assess the risks to health from hazardous substances such as welding fume (regulation 6)
Adequately control the risk to health (regulation 7)
Maintain, examine and check controls (regulation 9)
Provide health surveillance where appropriate (regulation 11).

Regulation 12 of COSHH also requires employers to inform, instruct and train workers who are exposed to welding fume on:

The health risks
How to report any ill health symptoms
How to use controls to prevent ill health occurring.

The Control of Lead at Work (CLAW) Regulations 2002 require employers to:

Assess the risk from welding and allied processes which result in exposure to lead dust and fumes, eg from lead-based paint on metal (regulation 5)
Prevent or control exposure to lead (regulation 6)
Maintain, examine and check controls (regulation 8)
Carry out air monitoring where there is likely to be significant exposure to lead (regulation 9)
Provide medical surveillance(regulation 10).

Air monitoring is a specialist activity. A qualified occupational hygienist can ensure it is carried out in a way that provides meaningful and helpful results.

The monitoring information can be used to:

help to inform the COSHH assessment for the task as it gives an illustration of the exposure risk
help to select the right fume control solutions
check that exposure limits are not exceeded
check that controls work well enough, or if improvements are needed
check that new controls work well enough
help choose the right level of respiratory protection
influence the health surveillance programme.

Legal Requirements

The monitoring information can be used to:

help to inform the COSHH assessment for the task as it gives an illustration of the exposure risk
help to select the right fume control solutions
check that exposure limits are not exceeded
check that controls work well enough, or if improvements are needed
check that new controls work well enough
help choose the right level of respiratory protection
influence the health surveillance programme.

What do the results mean and how to interpret them?

Personal air monitoring results can be compared with the relevant set workplace exposure limits (WELs) which are published in the HSE book EH40/2005: Workplace Exposure Limits In-house limits can also be set and used to compare with results for task-specific exposures.

There is no single WEL for welding fume. Therefore, exposure measurements should be compared to the appropriate limits for the different constituents in the welding fume, such as: iron oxide, hexavalent chromium, nickel and manganese. Hexavalent chromium and nickel in welding fume are both defined occupational carcinogens.

This means that there is a requirement to reduce exposure to these constituents to a concentration which is as low as is reasonably practicable (ALARP). For other substances which have a WEL but are not carcinogens or can cause asthma, adequate control of exposure will involve controlling exposure to below the WEL.

Any revised WEL, which might be implemented, will require improved fume control measures for many welding processes.

When is air monitoring needed?

An air monitoring survey can also use suitable fixed-site air samplers (also known as static samplers) to provide an overall assessment of airborne concentrations of a substance. Fixed-site air samplers do not directly represent employee or personal exposure.

However, these results can help identify:

loss of good fume control
sources of fume contributing to exposure
the extent of spread from the point of welding.

What exposure monitoring isn’t

Air monitoring and biological monitoring are not a substitute for putting good fume control solutions in place to protect the health of workers. You can also use other methods to demonstrate that exposure to welding fume is adequately controlled.

Why biological monitoring for welding fume exposure measurement is needed

When would you carry out biological monitoring?

The monitoring information can be used to:

help to inform the COSHH assessment for the task as it gives an illustration of the exposure risk
help to select the right fume control solutions
check that exposure limits are not exceeded
check that controls work well enough, or if improvements are needed
check that new controls work well enough
help choose the right level of respiratory protection
influence the health surveillance programme.

Practicalities in setting up a biological monitoring programme

Employees cannot be compelled to provide biological monitoring samples without consent. Biological monitoring is a specialist activity. Urine samples are usually collected by either an occupational hygienist (www.bohs.org), or occupational health professional (doctor or nurse) (www.som.org.uk). The samples are then sent to a specialist laboratory (www.hsl.gov.uk) for analysis by post.