Welding is a common industrial activity and there are a number of health hazards associated with welding. These hazards include
- Welding Fumes. These are very fine solid particles (mainly metal oxides) temporarily suspended in the air. These can be breathed in by welders without adequate RPE (Respiratory Protective Equipment), or by staff passing by. Some of these fumes are highly toxic. Due to the small size of welding fume particles compared to normal dust, these penetrate further into the lungs and hence can cause more damage.
- Gases. These may include ozone, and for MIG and TIG welding, inert gases. Inert gases can present a problem in confined spaces as they may displace oxygen.
- UV radiation from the welding arc. A common manifestation of UV radiation is so called ‘arc eye’ or ‘welders’ eye’. This is a painful condition. The UV radiation will also generate ozone.
There are estimated to be 190,000[1] workers engaged in welding in the UK and 12,200[2] in Ireland. This is a significant number of workers and it is absolutely essential that effects of welding fumes are understood so they can be managed.
The main health hazard, particularly with manual metal arc (stick welding) and MIG welding are the welding fumes. The majority of metal being welded is mild steel and the weld fume will therefore consist of mainly iron oxide.
Besides iron oxide, there will be manganese. Mild steel contains traces of manganese, welding rods and wire also contain small quantities of magnesium. The Occupational Exposure Limit Value (OELV) for manganese is significantly lower than that for iron oxide fume (and is proposed to be even lower in 2018). This is because repeated exposure to low concentrations of manganese have been shown to affect the nervous system.
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.
There are prescribed Occupational Exposure Limit Values for metal fumes, ozone and other substances. In order to ensure welders and others are adequately protected it is essential to carry out workplace air monitoring (aka occupational air monitoring). This will measure the amounts of metal fume in the air and determine the concentration. This concentration is then standardised for an 8 hour shift and compared to the relevant legislation[3].
In addition to monitoring, Environmental Efficiency can evaluate the existing control measures, such as RPE, and propose any necessary improvements. One particular control measure is LEV (Local Exhaust Ventilation) and Environmental Efficiency has many years of inspecting these systems to determine their effectiveness.
It will be necessary to repeat the monitoring from time to time even if the monitoring results give the all clear. The re-monitoring interval depends on how close the results are to the OELV. BS EN 689:1966 gives useful guidance on re-monitoring. Re-monitoring should also be considered after any process change or change in intensity of activity. For example, revised workshop layouts, welding of larger fabrications or increased numbers of welders would be reason to consider re-monitoring.
One final point is that monitoring of workers is not only good for their health, but can protect you from spurious legal claims. If you have no history of workplace air monitoring (and good results), it can be difficult to defend a claim in court.
Environmental Efficiency offers workplace air monitoring and LEV assessments across Ireland and the UK. Environmental Efficiency has a wide range of sampling equipment and media available in-house and can respond quickly to any monitoring requirement. For further information on workplace monitoring please contact us our environmental consultants at Bray or one of our local offices.
[1] BOHS
[2] CSO QNHS Employment Q1 2017 Metal Forming, welding and related trades.
[3] For UK: EH40/2005 Workplace exposure limits. Ireland: 2016 Code of practice for the Chemical Agents Regulations.