Health risks from welding

Gases and fine particles in welding fume can cause dryness of the throat, coughing or tightness in the chest. The effects tend to be shortlived. Ozone in particular can cause this when tungsten inert gas (TIG) welding stainless steels and aluminium. High exposures to nitrous oxides (generated during most arc welding) can also cause irritation. Extreme exposure to ozone can cause fluid on the lungs.

Very high levels of exposure to inhaled irritants can cause asthma to develop, but this is not common. This condition used to be known as reactive airways dysfunction syndrome.

Many welders get flu-like symptoms after welding. The effects are often worse at the start of the working week. Metal fume fever is usually linked to welding or hot work on galvanised metals. High exposures to mild steel weld fume can also cause this illness.

Metal fume fever does not usually have any lasting ill effects. It often starts a few hours after exposure begins and carries on for a while after exposure ends.

Welders are at an increased risk of developing pneumococcal pneumonia, due to breathing in welding fume. Welders are particularly prone to a lung infection that can lead to severe and sometimes fatal pneumonia.

Pneumonia kills about 2 welders a year. It can affect young welders as well as older people. Exposure to welding fume in the past does not increase the chances of you getting pneumonia now. A vaccination is available to reduce the risk of pneumonia if you are a welder. However, the vaccination is not a substitution for good exposure control. Further guidance is available in Pneumonia vaccination for employees exposed to welding and metal fume.

Many studies report increased risk of lung cancer in welders or other workers exposed to welding fume. The International Association for Research on Cancer (IARC) conclude that all welding fume can cause lung cancer and may cause kidney cancer, classifying all welding fume as Group 1 carcinogenic substances.

HSE commissioned an independent expert view on the IARC report from the Workplace Health Expert Committee, who agreed the report findings. As a result, HSE issued a Safety Alert in February 2019 about the link between mild steel welding fume and cancer.

Assessment of the strength of evidence underpinning the IARC reclassification of welding fume as carcinogenic to humans - WHEC-11a (PDF)

Current evidence suggests that exposure to welding fume may cause COPD, but there is not enough evidence to prove a definitive link. Normally seen in smokers, lung function can decline more quickly than expected, and fume may contribute to this decline. Established COPD causes progressive shortness of breath, chest tightness and wheeze. It may also cause fatigue. If the illness does progress, workers can become very severely incapacitated.

Welder's lung normally describes metal deposition in the lung from exposure to welding fume. It is thought to be a benign type of pneumoconiosis. On its own, the welder may not complain of health problems. However, if COPD also exists, welder's lung could make the COPD symptoms worse.

Occupational asthma can be caused by metals in the welding fume, for example by hexavalent chromium, nickel and cobalt. Stainless steel welding fume will contain these metals and some types of welding, for example MMA lead to more of these in the fume.

Occupational asthma symptoms include episodes of severe shortness of breath, wheezing, coughing and chest tightness. It usually involves a latency period of a few months to a few years between first exposure to a respiratory sensitiser in the workplace, and symptoms starting.

Welders with occupational asthma can also develop a short-term temporary reduction in lung function. This is sometimes also seen in welders without asthma.

Welding in confined spaces can lead to death from asphyxiation (suffocation from lack of oxygen). This can be caused by exposure to:

• carbon monoxide which can form carboxyhaemoglobin. This can impair the oxygen-carrying capacity of the blood. Symptoms of overexposure include headache, dizziness and nausea
• shielding gases (such as argon, helium and nitrogen, or argon-based mixtures containing carbon dioxide, oxygen or both), because of an accumulation of the gases and displacement of oxygen in confined and enclosed spaces

Welding in a confined space must only be carried out when absolutely necessary, as this is a high risk task.

Further information on this can be found at safety risks and welding.

Nickel and chromium released during welding may cause allergic contact dermatitis. Welders' skin can also be exposed to ultraviolet radiation. Reddening, or erythema, of the skin, like a patch of sunburn, is the commonest skin problem.

Studies suggest that exposure to manganese, present in mild steel welding fume, can lead to neurological symptoms similar to Parkinson's disease. These symptoms include speech and balance disorders. There are new studies underway in this area that will help HSE decide whether more action is needed.

The respirable manganese WEL of 0.05mg/m3 (8hr TWA) is appropriate because much of the manganese in the fume will be small particles that reach the deep lung (known as respirable particles).

When the manganese fume particles are breathed in routinely over a period of time they cause a systemic effect. This means the manganese can be absorbed into the body through many routes and can cause neurological effects.

It is highly likely that the respirable manganese WEL will be exceeded during many welding activities unless effective controls are introduced and used properly. You could carry out exposure monitoring to see if you are complying with the WEL.

This rare cancer of the eye can be associated with welding, particularly the ultraviolet radiation generated from welding. This reinforces the need to protect the eyes when welding.

Arc-eye is an acute injury to the front of the eye (the cornea) after exposure to radiation generated by welding. Normally the eye becomes painful and red a few hours after welding. Other parts of the eye can also be damaged by exposure to the radiation produced in welding. This reinforces the need to protect the eyes when welding.

Vibration

Welding and hot cutting processes do not usually generate harmful levels of vibration. But there may be a risk from some associated tasks like grinding, needle scaling etc. For more information and HSE's 'vibration exposure calculator' go to the HSE hand-arm vibration pages.

Noise

With the exception of TIG, electric arc welding generates harmful levels of noise. The process itself produces noise, the other tasks that a welder will typically do are also noisy, and welding is generally carried out in a noisy environment. Noise levels experienced during arc welding and cutting vary with the process. The table gives typical noise levels for different types of welding process and associated tasks.

The actual noise levels will depend on several factors. For instance, noise is likely to increase with increasing consumable diameter and with increasing current. Also, the type of metal being worked will have an effect. Stainless steel tends to produce higher noise levels than mild steel.

Where cutting is concerned, the thickness of material being cut will affect the noise produced, thicker materials being noisier.

For the loudest processes (plasma cutting and air arc gouging) the dominant source of noise is the high-pressure compressed air. The design of air nozzle can have a big effect on noise emission and some companies may offer 'reduced noise' equipment.

Typical noise exposure

Daily personal noise exposure depends both on the level of noise (the dB(A) value) and the time of exposure during a working day. When assessing potential noise exposure, it is important to consider how long welding operations last. For welding and hot cutting processes, noise is only generated when an arc is struck or flame lit. A production welder's 'arcing' time may be as much as 80% of the shift. A fabricator welder may spend most of the day setting the job up before starting any welding. Sometimes setting up can be fairly quiet, for example marking out. At other times it can be quite noisy, for example edge preparation by manual grinding.

Welders also often work in noisy environments and carry out other noisy operations, such as needle scaling and grinding. It is likely that a welder's individual noise exposure will be affected not only by their own work, but also by the work of their colleagues.

You should consider these factors when assessing noise risk. Underestimating noise risk could lead to damaged hearing. But over-estimating noise exposure could lead to unnecessary expense or overprotection.

Control measures

Employers should eliminate the noisy process where possible, perhaps by buying in the material cut to size by the supplier. But welding and hot cutting is often the only practical method, so the main focus should be on:

• using practical methods to reduce noise levels for the given process
• managing the residual risk using ear plugs, ear muffs or other hearing protection

An example of this would be moving from hand-held plasma cutting to an automated submerged plasma cutter. This can keep noise levels below 80 dB(A). Water-shrouded plasma cutters are available and may be practical for some operations. Submerged or water-shrouded systems reduce fume emission as well as noise. With any alternative ways of working, weigh the practicality of the alternative and investment required against the benefits (health, safety, productivity, etc):

• As a general rule, noise from arc welding increases with wire/rod diameter and operating current. Using a wire/rod size and current appropriate for the job and not excessively large should help to minimise noise levels
• With plasma/flame cutting and arc gouging, noise levels generally increase with increasing gas velocity. Ensuring that the gas velocity is as low as possible (for example reducing the outlet pressure at the regulator) will generally reduce the noise levels. There is a trade-off between productivity rate and gas pressure. But there will be a crossover where increased gas pressure does not significantly increase productivity
• Welding in confined spaces or other areas where sound may be reflected (such as the corner of a workshop) can give higher noise levels than if the welding is carried out in an open space. If it is not possible to organise the work to avoid these situations, adding sound-absorbing materials to the reflective surfaces can help reduce the impact of the welding noise on other people working nearby

Hearing protection

Hearing protection selection should be based on 4 criteria:

• its ability to reduce noise exposure
• its compatibility with other PPE (welding masks, safety helmets etc)
• comfort
• suitability for the working environment and activity

Ear plugs and slimline ear muffs with a neckband rather than a headband may be more compatible with welding masks.

If hearing protection is used as the main control in reducing noise exposure, workers should be trained in its use. Workers should wear the protection all the time they are in a noisy area, or doing noisy work. Hearing protection becomes significantly less effective if workers do not use it for even a small amount of the time they are exposed.

There is more information on HSE's noise and vibration web pages.