HSE update: Mild Steel Welding Fume is Carcinogenic

Outsource Safety LtdSafety newsHSE update: Mild Steel Welding Fume is Carcinogenic
June 20, 2019 Posted by Roger Hart

You may have seen the recent HSE update announcing mild steel welding fume is carcinogenic and IARCs new classification of it as a carcinogen (cancer-causing agent).  This has caused a huge amount of questions for both our helpline for existing client supported under Safety~net and also from our work monitoring welding fume exposure, you can also watch our 3 minute video below


We have completed many sampling exercises over the last 25 years and often work to submit our reports back to the Health and Safety Executive on behalf of the client and also represent their interests when HSE have concerns. If you have any concerns please do contact us or request a call back from one of our safety consultants or an occupational hygienist.

from IARC: “The International Agency for Research on Cancer (IARC) highlighted environmental factors that could cause cancer in humans, including the fumes generated during welding operations. Welding fumes could produce several negative health effects, including respiratory problems and lung cancer due to prolonged exposure. Recently, the IARC, the cancer research arm of the World Health Organization, classified welding fumes as possibly carcinogenic to humans after there have been studies indicating welding fumes and gases may increase cancer risks.”

What is the impact of the reclassification of mild steel welding fume?Mild Steel Welding Fume Carcinogenic

Firstly, don’t panic. Mild Steel Welding Fume is Carcinogenic but welding fumes have always been harmful and you will have some protection already in place through local exhaust ventilation, disposable masks or perhaps air fed helmets for your welders.  Now you need to review these controls to ensure that they are adequate and also make allowance for the higher known level of risk, so what you might choose to do may change in light of this.  For example, if you decided previously that you could not justify the expense of air fed helmets you might wish to review that decision.

Secondly, take advice on HSE’s comments on LEV being the key requirement.  Whilst its true that a well designed LEV system is most likely the best way forward you cannot always have this in place when work positions and work types change and vary.  We’ve seen some great systems for serial production of the same items but we’ve also seen systems which rely on the welder using them and moving them sat unused for month after month. What works best can vary and sometimes we do need to rely on personal protection through an air fed helmet.

How do I monitor for exposure to mild steel welding fume?

It’s quite straightforward but you do need to be competent.  Its typically carried out through air monitoring by an Occupational Hygienist and its something which we have offered for many years. A volume of air is drawn through a filter and the mass measured, 90% of fume is made up of the consumable and so the permissible amount of exposure does vary between suppliers and also is affected by other factors, for example;

  1. Welding position:
    1. does the welding plume rise into the welder’s face?
    2. Is the weld below the worker (down hand position)?
    3. Is the weld completed within a workshop?
    4. Is the weld completed within a confined space?
  2. Current controls:
    1. Are disposable masks in use?
    2. Is an air fed welding helmet available?
    3. Is LEV provided?
    4. Is LEV used consistently?
    5. Is the LEV effective in capturing the fume?
  3. Exposure considerations:
    1. Is the parent metal coated?
      1. Galvanised or painted surfaces are much higher risk exposures
    2. Is the weld completed within the structure?
      1. Fumes could build up to very high levels
    3. Are their others nearby who will be affected?
      1. For smaller work zones this could be significant
  4. Other factors:
    1. Process variables such as amps and feed speed can increase fume exposure
    2. Changes in the process from TIG to MIG or MMA welding can also adversely affect fume generation

See how on gun extraction could help: Binzel on torch extraction, welding fume to the right is what our client found in its waste tray after around 2 months of use;

What can I do to reduce exposure to welding fume?Welding fume

You can look to outsource or automate the process if possible.  LEV is a great solution when it is practicable but often it needs to be moved constantly to remain effective (LEV only works effectively within 1 diameter, i.e. if the end of the extract arm is 100mm it MUST remain within 100mm of the weld points at ALL TIMES.  If you have weld seams which are longer than a few centimetres this often proves difficult as a welder does not have a free arm with which to move the LEV point whilst welding.

You then need to consider another method of control, these could be:

  1. Updating you LEV to extract over a wider area through use of a booth, a downdraft bench or other extracted enclosure;
    1. Please review the welding fume RPE selector from BOHS: http://www.breathefreely.org.uk/wst/
  2. Using air fed welding helmets, these give protection to your workers wherever they are but may be overwhelmed in confined spaces;
  3. using on gun extraction to capture fume at source (see our video for a demonstration: https://youtu.be/-JywnVZJLNk);
  4. Swapping welding methods, TIG usually generates less fume than MIG;
  5. Adjusting settings, you might be able to reduce the weld current to reduce fume;
  6. reducing concurrent exposures, you may be able to remove paint, oil or other coatings before the area is welded.

View the revised HSE Guidance on fume control here; http://www.hse.gov.uk/pubns/guidance/wl3.pdf