Welding is one of the most common activities carried out in industry. HSE estimate that there are around 190,000 welders in UK. However, this is likely to be an underestimate of the total number of workers who carry out welding as there is likely to be a large number who do a small amount of welding on an occasional basis.
There are a number of health hazards associated with welding in particular:
- Gases, including ozone and, with MIG and TIG welding, inert gases that can present a problem when working in confined spaces
- UV radiation from the welding arc. This can effect the eye (“arc eye”) and skin and is also responsible for the generation of ozone from atmospheric oxygen.
The main health hazard with many welding operations – particularly MMA (stick) and MIG welding – is the welding fume. This consists of very fine particles of metal oxides, mainly arising from the welding rod or wire.
The composition of the fume varies depending on the metal being welded. With mild steel it will mainly consist of iron oxide but there is also likely to be a small percentage of manganese which is used in welding rods. Repeated exposure to low concentrations of manganese have been shown to affect the nervous system and the Workplace Exposure Limit for manganese will be reduced significantly in 2018. Stainless steel welding is particularly hazardous as the fume contains nickel and chromium VI oxides which are highly toxic if inhaled – both are carcinogens and can also cause occupational asthma.
As well as the fume (particulate), Arc welders will also be exposed to gases. Ozone is produced by the action of the UV from the arc on oxygen in the air. It is highly irritant to the eyes and respiratory system. In some cases, particularly with thicker plate, atmospheric nitrogen can be converted to highly irritant nitrogen oxides. With MIG and TIG welding the inert gas used to stop the weld oxidising will be released. This should not present a risk when welding outdoors or in a well ventilated area, but can present a serious risk of asphyxiation in a confined space.
The UK Health and Safety Executive estimate that exposure to welding fume causes more than 150 deaths due to cancer every year. Exposure to the fume and gases can also cause other diseases including
- Metal fume fever
Many welders are exposed unnecessarily to welding fume. Control measures are available – but it’s important to make sure the right controls are used – there is not one solution that will be effective in all cases.