Welding Risk Assessment

Welding fume is classified by the International Agency for Research on Cancer as carcinogenic to humans, and in January 2024 work health and safety ministers agreed to cut the workplace exposure standard for welding fume (not otherwise classified) from 5 mg/m³ to 1 mg/m³ as an eight-hour time-weighted average. Individual components of the fume – hexavalent chromium, nickel, manganese and others – have their own, often much lower, exposure standards, and exposure must be kept below each of them. The practical effect is that arrangements many workshops have relied on for years – an open roller door, a pedestal fan, a disposable dust mask – are no longer a defensible answer. A regulator will ask what you have at the source and what your air monitoring shows.

A welding risk assessment has to deal with the health hazards as seriously as the burns and the fires. The model Code of Practice Welding processes is the reference.

The fume depends on what is being welded, what it is coated with, the process and the consumable.

• Mild steel – iron oxide and manganese.
• Galvanised steel – zinc oxide, the cause of metal fume fever.
• Stainless steel – hexavalent chromium and nickel, both carcinogens. This is the highest-risk welding most workshops do.
• Aluminium – aluminium oxide, and high levels of ozone from MIG and TIG.
• Coatings and residues – paints, primers, oils and degreasing solvents. Chlorinated solvents near an arc can form phosgene.

Gases matter too: ozone, nitrogen oxides, carbon monoxide, and shielding gases that displace air in confined spaces.

Follow the hierarchy of control:

1. Eliminate or substitute – cold joining, a lower-fume process or consumable, removing coatings before welding.
2. Engineering – on-torch extraction, a capture hood or extraction arm positioned close to the arc, downdraught benches, and general ventilation in support. Local exhaust ventilation needs to be tested and maintained or it quietly stops working.
3. Administrative – positioning so the welder's head is out of the plume, limiting time, keeping others away.
4. Respiratory protection – powered air-purifying welding helmets or a correctly selected, fit-tested respirator.

Where it is uncertain whether the exposure standard is exceeded, air monitoring by an occupational hygienist is required, and health monitoring may be needed for some contaminants.

When monitoring is needed. The WHS Regulations require air monitoring where you are not certain, on reasonable grounds, whether an exposure standard is exceeded, or where monitoring is needed to work out whether there is a risk to health. With the welding fume standard at 1 mg/m³, very few welding bays can be confident without measuring. Stainless steel work, confined or poorly ventilated spaces, and high-production MIG welding are the priorities.

How it is done. An occupational hygienist places a sampler in the welder's breathing zone – inside the welding helmet – for a representative shift, and the sample is analysed for total fume and the metals of concern. Results are compared with the exposure standards and reported with recommendations.

What to do with the result. Records of air monitoring must be kept for 30 years and be readily accessible to the workers who were exposed. If results are at or near the standard, improve the controls first and re-test; do not reach straight for a respirator.

Health monitoring is required for workers with significant exposure to certain substances, including chromium (inorganic). Your hygienist or an occupational physician can advise whether it applies.

• Electric shock – damaged leads and holders, wet conditions, poor work return connections. Voltage-reducing devices on stick welders.
• UV and infrared radiation – arc eye and skin burns, for the welder and for anyone nearby without screens.
• Fire and explosion – sparks and hot metal travelling metres to reach combustibles; drums and tanks that once held flammables. Hot work permits and a fire watch.
• Burns from spatter, slag and hot workpieces.
• Gas cylinders – securing, flashback arrestors, leak checks.
• Noise from gouging, grinding and chipping.
• Hazardous manual tasks and awkward postures.
• Confined spaces – fume build-up, displaced oxygen, difficult rescue.
• Pickling and passivation of stainless welds – pastes that contain hydrofluoric acid, which is absorbed through the skin and can be fatal in small burns.

Hazard: fume from MIG welding of stainless steel. Inherent risk 4D – red: occupational cancer is a permanent, life-limiting outcome, and exposure occurs on every shift.

Found on the walkthrough: an extraction arm in the bay, usually parked a metre from the arc; roller door open; disposable P2 respirators available, not fit-tested; no air monitoring; no health monitoring.

An extraction arm that is not at the arc captures very little, so the engineering control earns little credit and the residual risk stays red. The action plan, most effective first:

1. On-torch extraction, or the arm positioned as close to the arc as the work allows – as a guide, within about one duct diameter – and moved as the weld progresses.
2. Powered air-purifying welding helmets for stainless work.
3. Air monitoring for hexavalent chromium and total fume to confirm the controls work.
4. Health monitoring on the hygienist's or physician's advice.
5. Local exhaust ventilation on a test and maintenance schedule.

Our Welding and Fabrication risk assessment treats galvanised steel, stainless steel and aluminium separately, then covers fabrication of ladders, platforms, nozzles and flanges, tack welding and fit-up, pickling and passivation, and zinc-rich touch-up: eight activities and 51 hazards in all, nearly half of them occupational hygiene hazards. Each hazard has its consequence and starting risk rated by a Certified Industrial Hygienist.

You answer Yes, No or N/A for each of 215 controls on the workshop floor. The calculator rates the residual risk, builds a prioritised action plan and produces a finished Word report. General ventilation is not accepted as an adequate control for carcinogenic fume – the scoring reflects the way a regulator thinks.