Staying safe around welding fume

In this article, we take a closer look at the dangers of welding fume and a strategic approach that can help to reduce exposure.

What is welding fume?

When selected work pieces are joined together via melting, microscopic particles of hot metal and gases are released from the welding arc.

These fumes can be inhaled by the welder or other people in the vicinity. If effective controls are not put in place, this can lead to significant short- and long-term health effects.

Welding fume can contain a mixture of airborne gases that may include oxides of nitrogen (NO_x), carbon monoxide (CO), carbon dioxide (CO₂), ozone (O₃) and shield gases including argon and helium.

The visible part of the fume cloud is mainly particles of metal, metal oxides and flux (if used). The exact level of risk from the fume will depend on what metals are involved in the work. Iron, aluminium, copper, lead, manganese, chromium and nickel can each have a different toxic effect on the body, so exposure needs to be effectively controlled.

The airborne concentrations and total exposure time to these fumes are also significant factors in determining the overall exposure of the welder.

Known health effects from welding exposures

There are a number of known health effects that can occur from welding exposures:

• Short-term exposures to significant levels of welding fume and gases can result in eye, nose and throat irritation, dizziness and nausea. Ozone is a particular cause of this when TIG welding stainless steels and aluminium.
• Long-term significant exposure to welding fume can cause lung damage and various types of cancer, including lung, larynx and urinary tract. Chromium (VI), a specific chemical form of chromium, can be created during welding of many stainless steels and non-ferrous alloys, and is highly toxic and can cause cancer. Certain fumes such as zinc may induce metal fume fever, stomach ulcers, kidney damage and nervous system damage. Prolonged exposure to manganese fume can cause Parkinson’s-like symptoms.
• Welders are particularly prone to a lung infection that can lead to severe and sometimes fatal pneumonia. Modern antibiotics are capable of stopping the infection; however, in severe cases the welder could end up in hospital.
• Asthma is a common complaint for welders, with components of stainless steel fume containing chromium oxide (CrO₃) and nickel oxide. For this reason, stainless steel welding fume is considered more harmful than mild steel fume.
• In early 2017, welding fume was reclassified from IARC classification Group 2B (possibly carcinogenic to humans) to Group 1 (carcinogenic to humans). This change was primarily associated with the effects of UV exposure on the skin and eyes and also for lung cancers and limited evidence for kidney cancer from welding fume exposures.

Strategies for reducing exposure to welding fume

Welders should understand the hazards of the materials with which they are working, referring to the relevant safety data sheets and identification of size and scale of exposures to welding fume.

OH&S regulations require employers to provide information and training for workers on exposure to hazardous materials in the workplace:

• Welding surfaces should be as clean as practicable of any coating or oil/grease that could potentially increase the overall exposure to airborne concentrations of hazardous particles or vapours.
• Workers should position themselves to avoid or reduce exposure to the welding fume and gases. For instance, welders can try to position themselves to be upwind when welding in open or outdoor environments. When working inside, welders should take advantage of any natural drafts by positioning themselves to keep fume and gases away from themselves and other workers.
• Local exhaust ventilation systems can be used to remove fume and gases from the welder’s breathing zone. Any air extraction system inlet should be located as close to the plume source as possible to remove the maximum amount of fume and gases. Keep any exhaust points away from other workers.
• Investigate consumable options to see if there are less toxic alternatives or a welding type that produces less fume.
• Use appropriate respiratory protection equipment.

Image courtesy of AWS.